Merge branch 'master' into webview-markdown

30 files changed, 378 insertions, 198 deletions

diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/api/DeckAPI.java b/app/src/main/java/it/niedermann/nextcloud/deck/api/DeckAPI.java
index a303a8a33..1f0148b91 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/api/DeckAPI.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/api/DeckAPI.java
@@ -1,6 +1,8 @@
 package it.niedermann.nextcloud.deck.api;
 
 
+import com.nextcloud.android.sso.api.ParsedResponse;
+
 import java.util.List;
 
 import io.reactivex.Observable;
@@ -33,6 +35,7 @@ import retrofit2.http.Query;
 public interface DeckAPI {
 
     String MODIFIED_SINCE_HEADER = "If-Modified-Since";
+    String IF_NONE_MATCH = "If-None-Match";
 
     // ### BOARDS
     @POST("boards")
@@ -51,7 +54,7 @@ public interface DeckAPI {
     Observable<FullBoard> restoreBoard(@Path("id") long id);
 
     @GET("boards")
-    Observable<List<FullBoard>> getBoards(@Query ("details") boolean verbose, @Header(MODIFIED_SINCE_HEADER) String lastSync );
+    Observable<ParsedResponse<List<FullBoard>>> getBoards(@Query ("details") boolean verbose, @Header(MODIFIED_SINCE_HEADER) String lastSync, @Header(IF_NONE_MATCH) String eTag);
 
 
     // ### Stacks
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/api/IResponseCallback.java b/app/src/main/java/it/niedermann/nextcloud/deck/api/IResponseCallback.java
index 0e523c318..be3eaeb22 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/api/IResponseCallback.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/api/IResponseCallback.java
@@ -24,12 +24,18 @@ public abstract class IResponseCallback<T> {
         DeckLog.logError(throwable);
     }
 
+    @CallSuper
+    public void onError(Throwable throwable, T locallyCreatedEntity) {
+        onError(throwable);
+    }
+
     public static <T> IResponseCallback<T> getDefaultResponseCallback(Account account) {
         return new IResponseCallback<T>(account) {
             @Override
             public void onResponse(T response) {
                 // Do Nothing
             }
+
         };
     }
 
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/api/JsonToEntityParser.java b/app/src/main/java/it/niedermann/nextcloud/deck/api/JsonToEntityParser.java
index 8601cab41..e759f27d4 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/api/JsonToEntityParser.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/api/JsonToEntityParser.java
@@ -284,6 +284,7 @@ public class JsonToEntityParser {
         makeTraceableIfFails(() -> {
             board.setTitle(getNullAsEmptyString(e.get("title")));
             board.setColor(getNullAsEmptyString(e.get("color")));
+            board.setEtag(getNullAsNull(e.get("ETag")));
             board.setArchived(e.get("archived").getAsBoolean());
 
             board.setLastModified(getTimestampFromLong(e.get("lastModified")));
@@ -396,6 +397,7 @@ public class JsonToEntityParser {
             card.setDescription(getNullAsEmptyString(e.get("description")));
             card.setStackId(e.get("stackId").getAsLong());
             card.setType(getNullAsEmptyString(e.get("type")));
+            card.setEtag(getNullAsNull(e.get("ETag")));
             card.setLastModified(getTimestampFromLong(e.get("lastModified")));
             card.setCreatedAt(getTimestampFromLong(e.get("createdAt")));
             card.setDeletedAt(getTimestampFromLong(e.get("deletedAt")));
@@ -456,6 +458,7 @@ public class JsonToEntityParser {
             a.setId(e.get("id").getAsLong());
             a.setCardId(e.get("cardId").getAsLong());
             a.setType(e.get("type").getAsString());
+            a.setEtag(getNullAsNull(e.get("ETag")));
             a.setData(e.get("data").getAsString());
             a.setLastModified(getTimestampFromLong(e.get("lastModified")));
             a.setCreatedAt(getTimestampFromLong(e.get("createdAt")));
@@ -571,33 +574,6 @@ public class JsonToEntityParser {
         return Color.GRAY;
     }
 
-    protected static List<Activity> parseActivity(JsonObject e) {
-        DeckLog.verbose(e.toString());
-        List<Activity> activityList = new ArrayList<>();
-
-        makeTraceableIfFails(() -> {
-            if (e.has("ocs")) {
-                JsonObject ocs = e.getAsJsonObject("ocs");
-                if (ocs.has("data")) {
-                    JsonArray data = ocs.getAsJsonArray("data");
-                    for (JsonElement activityJson : data) {
-                        Activity activity = new Activity();
-                        JsonObject activityObject = activityJson.getAsJsonObject();
-
-                        activity.setId(activityObject.get("activity_id").getAsLong());
-                        activity.setType(ActivityType.findByPath(getNullAsEmptyString(activityObject.get("icon"))).getId());
-                        activity.setSubject(getNullAsEmptyString(activityObject.get("subject")));
-                        activity.setCardId(activityObject.get("object_id").getAsLong());
-                        activity.setLastModified(getTimestampFromString(activityObject.get("datetime")));
-
-                        activityList.add(activity);
-                    }
-                }
-            }
-        }, e);
-        return activityList;
-    }
-
     protected static FullStack parseStack(JsonObject e) {
         DeckLog.verbose(e.toString());
         FullStack fullStack = new FullStack();
@@ -607,6 +583,7 @@ public class JsonToEntityParser {
             stack.setTitle(getNullAsEmptyString(e.get("title")));
             stack.setBoardId(e.get("boardId").getAsLong());
             stack.setId(e.get("id").getAsLong());
+            stack.setEtag(getNullAsNull(e.get("ETag")));
             stack.setLastModified(getTimestampFromLong(e.get("lastModified")));
             stack.setDeletedAt(getTimestampFromLong(e.get("deletedAt")));
             if (e.has("order") && !e.get("order").isJsonNull()) {
@@ -627,6 +604,34 @@ public class JsonToEntityParser {
         return fullStack;
     }
 
+    protected static List<Activity> parseActivity(JsonObject e) {
+        DeckLog.verbose(e.toString());
+        List<Activity> activityList = new ArrayList<>();
+
+        makeTraceableIfFails(() -> {
+            if (e.has("ocs")) {
+                JsonObject ocs = e.getAsJsonObject("ocs");
+                if (ocs.has("data")) {
+                    JsonArray data = ocs.getAsJsonArray("data");
+                    for (JsonElement activityJson : data) {
+                        Activity activity = new Activity();
+                        JsonObject activityObject = activityJson.getAsJsonObject();
+
+                        activity.setId(activityObject.get("activity_id").getAsLong());
+                        activity.setType(ActivityType.findByPath(getNullAsEmptyString(activityObject.get("icon"))).getId());
+                        activity.setSubject(getNullAsEmptyString(activityObject.get("subject")));
+                        activity.setCardId(activityObject.get("object_id").getAsLong());
+                        activity.setEtag(getNullAsNull(e.get("ETag")));
+                        activity.setLastModified(getTimestampFromString(activityObject.get("datetime")));
+
+                        activityList.add(activity);
+                    }
+                }
+            }
+        }, e);
+        return activityList;
+    }
+
     protected static Label parseLabel(JsonObject e) {
         DeckLog.verbose(e.toString());
         Label label = new Label();
@@ -635,13 +640,18 @@ public class JsonToEntityParser {
             //todo: last modified!
 //          label.setLastModified(get);
             label.setTitle(getNullAsEmptyString(e.get("title")));
+            label.setEtag(getNullAsNull(e.get("ETag")));
             label.setColor(getColorAsInt(e, "color"));
         }, e);
         return label;
     }
 
     private static String getNullAsEmptyString(JsonElement jsonElement) {
-        return jsonElement.isJsonNull() ? "" : jsonElement.getAsString();
+        return jsonElement == null || jsonElement.isJsonNull() ? "" : jsonElement.getAsString();
+    }
+
+    private static String getNullAsNull(JsonElement jsonElement) {
+        return jsonElement == null || jsonElement.isJsonNull() ? null : jsonElement.getAsString();
     }
 
     private static Instant getTimestampFromString(JsonElement jsonElement) {
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/exceptions/DeckException.java b/app/src/main/java/it/niedermann/nextcloud/deck/exceptions/DeckException.java
index d9d8c5dde..0512f8a60 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/exceptions/DeckException.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/exceptions/DeckException.java
@@ -5,7 +5,8 @@ public class DeckException extends IllegalArgumentException {
     public enum Hint {
         CAPABILITIES_NOT_PARSABLE,
         CAPABILITIES_VERSION_NOT_PARSABLE,
-        UNKNOWN_ACCOUNT_USER_ID
+        UNKNOWN_ACCOUNT_USER_ID,
+        DEPENDENCY_NOT_SYNCED_YET
     }
 
     private Hint hint;
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/exceptions/TraceableException.java b/app/src/main/java/it/niedermann/nextcloud/deck/exceptions/TraceableException.java
index 7acfb60bd..8d436477d 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/exceptions/TraceableException.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/exceptions/TraceableException.java
@@ -11,6 +11,8 @@ public class TraceableException extends RuntimeException {
     public static void makeTraceableIfFails(Runnable runnable, Object... args) {
         try {
             runnable.run();
+        } catch (TraceableException t) {
+            throw t;
         } catch (Throwable t) {
             final StringBuilder message = new StringBuilder("Sorry, a wild error appeared!\n\n" +
                     "⚠️ If you want to tell us about the following issue, " +
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/model/Account.java b/app/src/main/java/it/niedermann/nextcloud/deck/model/Account.java
index 1c189d162..8abcbced7 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/model/Account.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/model/Account.java
@@ -54,6 +54,7 @@ public class Account implements Serializable {
     private boolean maintenanceEnabled = false;
 
     private String etag;
+    private String boardsEtag;
 
     @Ignore
     public Account(Long id, @NonNull String name, @NonNull String userName, @NonNull String url) {
@@ -190,6 +191,14 @@ public class Account implements Serializable {
         this.etag = etag;
     }
 
+    public String getBoardsEtag() {
+        return boardsEtag;
+    }
+
+    public void setBoardsEtag(String boardsEtag) {
+        this.boardsEtag = boardsEtag;
+    }
+
     /**
      * A cache buster parameter is added for duplicate account names on different hosts which shall be fetched from the same {@link SingleSignOnAccount} (e. g. {@link AccountSwitcherDialog})
      *
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/model/Board.java b/app/src/main/java/it/niedermann/nextcloud/deck/model/Board.java
index f88594e7f..27dcd1df8 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/model/Board.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/model/Board.java
@@ -37,8 +37,8 @@ public class Board extends AbstractRemoteEntity implements Serializable {
     }
 
     @Ignore
-    public Board(String title, String color) {
-        this.title = title;
+    public Board(String title, @ColorInt int color) {
+        setTitle(title);
         setColor(color);
     }
 
@@ -98,7 +98,7 @@ public class Board extends AbstractRemoteEntity implements Serializable {
         }
     }
 
-    public void setColor(Integer color) {
+    public void setColor(@ColorInt Integer color) {
         this.color = color;
     }
 
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/model/interfaces/AbstractRemoteEntity.java b/app/src/main/java/it/niedermann/nextcloud/deck/model/interfaces/AbstractRemoteEntity.java
index 54cd0fc31..2f7771383 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/model/interfaces/AbstractRemoteEntity.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/model/interfaces/AbstractRemoteEntity.java
@@ -39,6 +39,8 @@ public abstract class AbstractRemoteEntity implements IRemoteEntity {
     protected Instant lastModified;
     protected Instant lastModifiedLocal;
 
+    protected String etag;
+
     public AbstractRemoteEntity() {
     }
 
@@ -137,6 +139,15 @@ public abstract class AbstractRemoteEntity implements IRemoteEntity {
         this.status = status.getId();
     }
 
+    @Override
+    public String getEtag() {
+        return etag;
+    }
+
+    @Override
+    public void setEtag(String etag) {
+        this.etag = etag;
+    }
 
     @Override
     public boolean equals(Object o) {
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/model/interfaces/IRemoteEntity.java b/app/src/main/java/it/niedermann/nextcloud/deck/model/interfaces/IRemoteEntity.java
index f50bf0b90..f197c0d30 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/model/interfaces/IRemoteEntity.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/model/interfaces/IRemoteEntity.java
@@ -68,6 +68,14 @@ public interface IRemoteEntity {
         getEntity().setStatusEnum(status);
     }
 
+    default String getEtag() {
+        return getEntity().getEtag();
+    }
+
+    default void setEtag(String etag) {
+        getEntity().setEtag(etag);
+    }
+
     default <T> List<T> copyList(List<T> listToCopy) {
         if (listToCopy == null) {
             return null;
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/SyncManager.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/SyncManager.java
index 0a7f213ef..c86f65340 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/SyncManager.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/SyncManager.java
@@ -527,8 +527,8 @@ public class SyncManager {
     }
 
     @AnyThread
-    public LiveData<FullBoard> createBoard(long accountId, @NonNull Board board) {
-        MutableLiveData<FullBoard> liveData = new MutableLiveData<>();
+    public WrappedLiveData<FullBoard> createBoard(long accountId, @NonNull Board board) {
+        WrappedLiveData<FullBoard> liveData = new WrappedLiveData<>();
         doAsync(() -> {
             Account account = dataBaseAdapter.getAccountByIdDirectly(accountId);
             User owner = dataBaseAdapter.getUserByUidDirectly(accountId, account.getUserName());
@@ -547,6 +547,12 @@ public class SyncManager {
                     public void onResponse(FullBoard response) {
                         liveData.postValue(response);
                     }
+
+                    @SuppressLint("MissingSuperCall")
+                    @Override
+                    public void onError(Throwable throwable, FullBoard entity) {
+                        liveData.postError(throwable, entity);
+                    }
                 });
             }
         });
@@ -907,7 +913,18 @@ public class SyncManager {
             stack.setBoardId(board.getLocalId());
             fullStack.setStack(stack);
             fullStack.setAccountId(accountId);
-            new DataPropagationHelper(serverAdapter, dataBaseAdapter).createEntity(new StackDataProvider(null, board), fullStack, getCallbackToLiveDataConverter(account, liveData));
+            new DataPropagationHelper(serverAdapter, dataBaseAdapter).createEntity(new StackDataProvider(null, board), fullStack, new IResponseCallback<FullStack>(account) {
+                @Override
+                public void onResponse(FullStack response) {
+                    liveData.postValue(response);
+                }
+
+                @SuppressLint("MissingSuperCall")
+                @Override
+                public void onError(Throwable throwable, FullStack entity) {
+                    liveData.postError(throwable, entity);
+                }
+            });
         });
         return liveData;
     }
@@ -1036,8 +1053,8 @@ public class SyncManager {
 //    }
 
     @AnyThread
-    public LiveData<FullCard> createFullCard(long accountId, long localBoardId, long localStackId, @NonNull FullCard card) {
-        MutableLiveData<FullCard> liveData = new MutableLiveData<>();
+    public WrappedLiveData<FullCard> createFullCard(long accountId, long localBoardId, long localStackId, @NonNull FullCard card) {
+        WrappedLiveData<FullCard> liveData = new WrappedLiveData<>();
         doAsync(() -> {
             Account account = dataBaseAdapter.getAccountByIdDirectly(accountId);
             User owner = dataBaseAdapter.getUserByUidDirectly(accountId, account.getUserName());
@@ -1074,11 +1091,28 @@ public class SyncManager {
                 }
             }
 
-            liveData.postValue(card);
+
             if (serverAdapter.hasInternetConnection()) {
                 new SyncHelper(serverAdapter, dataBaseAdapter, null)
-                        .setResponseCallback(IResponseCallback.getDefaultResponseCallback(account))
+                        .setResponseCallback(new IResponseCallback<Boolean>(account) {
+                            @Override
+                            public void onResponse(Boolean response) {
+                                liveData.postValue(card);
+                            }
+
+                            @SuppressLint("MissingSuperCall")
+                            @Override
+                            public void onError(Throwable throwable) {
+                                if (throwable.getClass() == DeckException.class && ((DeckException)throwable).getHint().equals(DeckException.Hint.DEPENDENCY_NOT_SYNCED_YET)) {
+                                    liveData.postValue(card);
+                                } else {
+                                    liveData.postError(throwable);
+                                }
+                            }
+                        })
                         .doUpSyncFor(new CardDataProvider(null, board, stack));
+            } else {
+                liveData.postValue(card);
             }
         });
         return liveData;
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/ServerAdapter.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/ServerAdapter.java
index a0b9fd8aa..bff8ddfdb 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/ServerAdapter.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/ServerAdapter.java
@@ -125,9 +125,9 @@ public class ServerAdapter {
 //        return lastSyncHeader;
     }
 
-    public void getBoards(IResponseCallback<List<FullBoard>> responseCallback) {
+    public void getBoards(IResponseCallback<ParsedResponse<List<FullBoard>>> responseCallback) {
         RequestHelper.request(provider, () ->
-                        provider.getDeckAPI().getBoards(true, getLastSyncDateFormatted(responseCallback.getAccount().getId())),
+                        provider.getDeckAPI().getBoards(true, getLastSyncDateFormatted(responseCallback.getAccount().getId()), responseCallback.getAccount().getBoardsEtag()),
                 responseCallback);
     }
 
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/DeckDatabase.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/DeckDatabase.java
index 0ac0f786b..a491946ed 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/DeckDatabase.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/DeckDatabase.java
@@ -97,7 +97,7 @@ import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.dao.widgets.Sta
                 UserInBoard.class,
         },
         exportSchema = false,
-        version = 22
+        version = 23
 )
 @TypeConverters({DateTypeConverter.class})
 public abstract class DeckDatabase extends RoomDatabase {
@@ -375,6 +375,25 @@ public abstract class DeckDatabase extends RoomDatabase {
         }
     };
 
+    private static final Migration MIGRATION_22_23 = new Migration(22, 23) {
+        @Override
+        public void migrate(SupportSQLiteDatabase database) {
+            // https://github.com/stefan-niedermann/nextcloud-deck/issues/359
+            database.execSQL("ALTER TABLE `Account` ADD `boardsEtag` TEXT");
+            database.execSQL("ALTER TABLE `Board` ADD `etag` TEXT");
+            database.execSQL("ALTER TABLE `Stack` ADD `etag` TEXT");
+            database.execSQL("ALTER TABLE `Card` ADD `etag` TEXT");
+            database.execSQL("ALTER TABLE `Label` ADD `etag` TEXT");
+            database.execSQL("ALTER TABLE `AccessControl` ADD `etag` TEXT");
+            database.execSQL("ALTER TABLE `Attachment` ADD `etag` TEXT");
+            database.execSQL("ALTER TABLE `User` ADD `etag` TEXT");
+            database.execSQL("ALTER TABLE `DeckComment` ADD `etag` TEXT");
+            database.execSQL("ALTER TABLE `Activity` ADD `etag` TEXT");
+            database.execSQL("ALTER TABLE `OcsProject` ADD `etag` TEXT");
+            database.execSQL("ALTER TABLE `OcsProjectResource` ADD `etag` TEXT");
+        }
+    };
+
     public static final RoomDatabase.Callback ON_CREATE_CALLBACK = new RoomDatabase.Callback() {
         @Override
         public void onCreate(@NonNull SupportSQLiteDatabase db) {
@@ -434,6 +453,7 @@ public abstract class DeckDatabase extends RoomDatabase {
                         lastSyncPref.apply();
                     }
                 })
+                .addMigrations(MIGRATION_22_23)
                 .fallbackToDestructiveMigration()
                 .addCallback(ON_CREATE_CALLBACK)
                 .build();
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/util/WrappedLiveData.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/util/WrappedLiveData.java
index 038fcbad8..003bceb26 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/util/WrappedLiveData.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/util/WrappedLiveData.java
@@ -1,5 +1,6 @@
 package it.niedermann.nextcloud.deck.persistence.sync.adapters.db.util;
 
+import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.lifecycle.MutableLiveData;
 
@@ -28,10 +29,13 @@ public class WrappedLiveData<T> extends MutableLiveData<T> {
     }
 
     public void postError(@Nullable Throwable error) {
+        postError(error, null);
+    }
+    public void postError(@Nullable Throwable error, @NonNull T locallyCreatedEntity) {
         if (error == null) {
             DeckLog.warn("Given error is null");
         }
         setError(error);
-        postValue(null);
+        postValue(locallyCreatedEntity);
     }
 }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/DataPropagationHelper.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/DataPropagationHelper.java
index 9590f5abd..782b6d951 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/DataPropagationHelper.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/DataPropagationHelper.java
@@ -34,27 +34,31 @@ public class DataPropagationHelper {
         entity.setLocalId(newID);
         boolean connected = serverAdapter.hasInternetConnection();
         if (connected) {
-            provider.createOnServer(serverAdapter, dataBaseAdapter, accountId, new IResponseCallback<T>(new Account(accountId)) {
-                @Override
-                public void onResponse(T response) {
-                    new Thread(() -> {
-                        response.setAccountId(accountId);
-                        response.setLocalId(newID);
-                        if (actionOnResponse!= null) {
-                            actionOnResponse.onResponse(entity, response);
-                        }
-                        response.setStatus(DBStatus.UP_TO_DATE.getId());
-                        provider.updateInDB(dataBaseAdapter, accountId, response, false);
-                        callback.onResponse(response);
-                    }).start();
-                }
+            try {
+                provider.createOnServer(serverAdapter, dataBaseAdapter, accountId, new IResponseCallback<T>(new Account(accountId)) {
+                    @Override
+                    public void onResponse(T response) {
+                        new Thread(() -> {
+                            response.setAccountId(accountId);
+                            response.setLocalId(newID);
+                            if (actionOnResponse != null) {
+                                actionOnResponse.onResponse(entity, response);
+                            }
+                            response.setStatus(DBStatus.UP_TO_DATE.getId());
+                            provider.updateInDB(dataBaseAdapter, accountId, response, false);
+                            callback.onResponse(response);
+                        }).start();
+                    }
 
-                @Override
-                public void onError(Throwable throwable) {
-                    super.onError(throwable);
-                    new Thread(() -> callback.onError(throwable)).start();
-                }
-            }, entity);
+                    @Override
+                    public void onError(Throwable throwable) {
+                        super.onError(throwable);
+                        new Thread(() -> callback.onError(throwable, entity)).start();
+                    }
+                }, entity);
+            } catch (Throwable t) {
+                callback.onError(t, entity);
+            }
         } else {
             callback.onResponse(entity);
         }
@@ -71,24 +75,28 @@ public class DataPropagationHelper {
         }
         boolean connected = serverAdapter.hasInternetConnection();
         if (entity.getId() != null && connected) {
-            provider.updateOnServer(serverAdapter, dataBaseAdapter, accountId, new IResponseCallback<T>(new Account(accountId)) {
-                @Override
-                public void onResponse(T response) {
-                    new Thread(() -> {
-                        entity.setStatus(DBStatus.UP_TO_DATE.getId());
-                        provider.updateInDB(dataBaseAdapter, accountId, entity, false);
-                        callback.onResponse(entity);
-                    }).start();
-                }
+            try {
+                provider.updateOnServer(serverAdapter, dataBaseAdapter, accountId, new IResponseCallback<T>(new Account(accountId)) {
+                    @Override
+                    public void onResponse(T response) {
+                        new Thread(() -> {
+                            entity.setStatus(DBStatus.UP_TO_DATE.getId());
+                            provider.updateInDB(dataBaseAdapter, accountId, entity, false);
+                            callback.onResponse(entity);
+                        }).start();
+                    }
 
-                @Override
-                public void onError(Throwable throwable) {
-                    super.onError(throwable);
-                    new Thread(() -> {
-                        callback.onError(throwable);
-                    }).start();
-                }
-            }, entity);
+                    @Override
+                    public void onError(Throwable throwable) {
+                        super.onError(throwable);
+                        new Thread(() -> {
+                            callback.onError(throwable, entity);
+                        }).start();
+                    }
+                }, entity);
+            } catch (Throwable t) {
+                callback.onError(t, entity);
+            }
         } else {
             callback.onResponse(entity);
         }
@@ -98,23 +106,28 @@ public class DataPropagationHelper {
         provider.deleteInDB(dataBaseAdapter, accountId, entity);
         boolean connected = serverAdapter.hasInternetConnection();
         if (entity.getId() != null && connected) {
-            provider.deleteOnServer(serverAdapter, accountId, new IResponseCallback<Void>(new Account(accountId)) {
-                @Override
-                public void onResponse(Void response) {
-                    new Thread(() -> {
-                        provider.deletePhysicallyInDB(dataBaseAdapter, accountId, entity);
-                        callback.onResponse(null);
-                    }).start();
-                }
+            try {
+                provider.deleteOnServer(serverAdapter, accountId, new IResponseCallback<Void>(new Account(accountId)) {
+                    @Override
+                    public void onResponse(Void response) {
+                        new Thread(() -> {
+                            provider.deletePhysicallyInDB(dataBaseAdapter, accountId, entity);
+                            callback.onResponse(null);
+                        }).start();
+                    }
+
+                    @Override
+                    public void onError(Throwable throwable) {
+                        super.onError(throwable);
+                        new Thread(() -> {
+                            callback.onError(throwable);
+                        }).start();
+                    }
+                }, entity, dataBaseAdapter);
+            } catch (Throwable t) {
+                callback.onError(t);
+            }
 
-                @Override
-                public void onError(Throwable throwable) {
-                    super.onError(throwable);
-                    new Thread(() -> {
-                        callback.onError(throwable);
-                    }).start();
-                }
-            }, entity, dataBaseAdapter);
         } else {
             callback.onResponse(null);
         }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/SyncHelper.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/SyncHelper.java
index 032c3594a..17c0de2cf 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/SyncHelper.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/SyncHelper.java
@@ -1,5 +1,11 @@
 package it.niedermann.nextcloud.deck.persistence.sync.helpers;
 
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+
+import com.nextcloud.android.sso.exceptions.NextcloudHttpRequestFailedException;
+
+import java.net.HttpURLConnection;
 import java.time.Instant;
 import java.util.List;
 import java.util.concurrent.CountDownLatch;
@@ -29,7 +35,7 @@ public class SyncHelper {
     }
 
     // Sync Server -> App
-    public <T extends IRemoteEntity> void doSyncFor(final AbstractSyncDataProvider<T> provider) {
+    public <T extends IRemoteEntity> void doSyncFor(@NonNull final AbstractSyncDataProvider<T> provider) {
         provider.registerChildInParent(provider);
         provider.getAllFromServer(serverAdapter, dataBaseAdapter, accountId, new IResponseCallback<List<T>>(account) {
             @Override
@@ -50,12 +56,13 @@ public class SyncHelper {
                         } else {
                             //TODO: how to handle deletes? what about archived?
                             if (existingEntity.getStatus() != DBStatus.UP_TO_DATE.getId()) {
-                                DeckLog.log("Conflicting changes on entity: " + existingEntity);
+                                DeckLog.warn("Conflicting changes on entity: " + existingEntity);
                                 // TODO: what to do?
                             } else {
-//                                if (existingEntity.getLastModified().getTime() == entityFromServer.getLastModified().getTime()) {
-//                                    continue; // TODO: is this is ok for sure? -> isn`t! NPE
-//                                }
+                                if (entityFromServer.getEtag() != null && entityFromServer.getEtag().equals(existingEntity.getEtag())) {
+                                    DeckLog.log("[" + provider.getClass().getSimpleName() + "] ETags do match! skipping " + existingEntity.getClass().getSimpleName() + " with localId: " + existingEntity.getLocalId());
+                                    continue;
+                                }
                                 provider.updateInDB(dataBaseAdapter, accountId, applyUpdatesFromRemote(provider, existingEntity, entityFromServer, accountId), false);
                             }
                         }
@@ -73,20 +80,29 @@ public class SyncHelper {
 
             @Override
             public void onError(Throwable throwable) {
+                super.onError(throwable);
+                if (throwable.getClass() == NextcloudHttpRequestFailedException.class) {
+                    NextcloudHttpRequestFailedException requestFailedException = (NextcloudHttpRequestFailedException) throwable;
+                    if (HttpURLConnection.HTTP_NOT_MODIFIED == requestFailedException.getStatusCode()){
+                        DeckLog.log("[" + provider.getClass().getSimpleName() + "] ETags do match! skipping this one.");
+                        // well, etags say we're fine here. no need to go deeper.
+                        provider.childDone(provider, responseCallback, false);
+                        return;
+                    }
+                }
                 provider.onError(throwable, responseCallback);
-                DeckLog.logError(throwable);
                 responseCallback.onError(throwable);
             }
         }, lastSync);
     }
 
     // Sync App -> Server
-    public <T extends IRemoteEntity> void doUpSyncFor(AbstractSyncDataProvider<T> provider) {
+    public <T extends IRemoteEntity> void doUpSyncFor(@NonNull AbstractSyncDataProvider<T> provider) {
         doUpSyncFor(provider, null);
     }
 
-    public <T extends IRemoteEntity> void doUpSyncFor(AbstractSyncDataProvider<T> provider, CountDownLatch countDownLatch) {
-        List<T> allFromDB = provider.getAllChangedFromDB(dataBaseAdapter, accountId, lastSync);
+    public <T extends IRemoteEntity> void doUpSyncFor(@NonNull AbstractSyncDataProvider<T> provider, @Nullable CountDownLatch countDownLatch) {
+        final List<T> allFromDB = provider.getAllChangedFromDB(dataBaseAdapter, accountId, lastSync);
         if (allFromDB != null && !allFromDB.isEmpty()) {
             for (T entity : allFromDB) {
                 if (entity.getId() != null) {
@@ -110,7 +126,7 @@ public class SyncHelper {
         }
     }
 
-    private <T extends IRemoteEntity> IResponseCallback<Void> getDeleteCallback(AbstractSyncDataProvider<T> provider, T entity) {
+    private <T extends IRemoteEntity> IResponseCallback<Void> getDeleteCallback(@NonNull AbstractSyncDataProvider<T> provider, T entity) {
         return new IResponseCallback<Void>(account) {
             @Override
             public void onResponse(Void response) {
@@ -126,7 +142,7 @@ public class SyncHelper {
         };
     }
 
-    private <T extends IRemoteEntity> IResponseCallback<T> getUpdateCallback(AbstractSyncDataProvider<T> provider, T entity, CountDownLatch countDownLatch) {
+    private <T extends IRemoteEntity> IResponseCallback<T> getUpdateCallback(@NonNull AbstractSyncDataProvider<T> provider, @NonNull T entity, @Nullable CountDownLatch countDownLatch) {
         return new IResponseCallback<T>(account) {
             @Override
             public void onResponse(T response) {
@@ -152,13 +168,13 @@ public class SyncHelper {
         };
     }
 
-    public void fixRelations(IRelationshipProvider relationshipProvider) {
+    public void fixRelations(@NonNull IRelationshipProvider relationshipProvider) {
         // this is OK, since the delete only affects records with status UP_TO_DATE
         relationshipProvider.deleteAllExisting(dataBaseAdapter, accountId);
         relationshipProvider.insertAllNecessary(dataBaseAdapter, accountId);
     }
 
-    private <T extends IRemoteEntity> T applyUpdatesFromRemote(AbstractSyncDataProvider<T> provider, T localEntity, T remoteEntity, Long accountId) {
+    private <T extends IRemoteEntity> T applyUpdatesFromRemote(@NonNull AbstractSyncDataProvider<T> provider, @NonNull T localEntity, @NonNull T remoteEntity, @NonNull Long accountId) {
         if (!accountId.equals(localEntity.getAccountId())) {
             throw new IllegalArgumentException("IDs of Accounts are not matching! WTF are you doin?!");
         }
@@ -167,7 +183,7 @@ public class SyncHelper {
         return remoteEntity;
     }
 
-    public SyncHelper setResponseCallback(IResponseCallback<Boolean> callback) {
+    public SyncHelper setResponseCallback(@NonNull IResponseCallback<Boolean> callback) {
         this.responseCallback = callback;
         this.account = responseCallback.getAccount();
         accountId = account.getId();
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/BoardDataProvider.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/BoardDataProvider.java
index 5b458471f..f5e071adb 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/BoardDataProvider.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/BoardDataProvider.java
@@ -1,5 +1,9 @@
 package it.niedermann.nextcloud.deck.persistence.sync.helpers.providers;
 
+import android.annotation.SuppressLint;
+
+import com.nextcloud.android.sso.api.ParsedResponse;
+
 import java.time.Instant;
 import java.util.ArrayList;
 import java.util.Collections;
@@ -26,8 +30,24 @@ public class BoardDataProvider extends AbstractSyncDataProvider<FullBoard> {
     }
 
     @Override
-    public void getAllFromServer(ServerAdapter serverAdapter, long accountId, IResponseCallback<List<FullBoard>> responder, Instant lastSync) {
-        serverAdapter.getBoards(responder);
+    public void getAllFromServer(ServerAdapter serverAdapter, DataBaseAdapter dataBaseAdapter, long accountId, IResponseCallback<List<FullBoard>> responder, Instant lastSync) {
+        serverAdapter.getBoards(new IResponseCallback<ParsedResponse<List<FullBoard>>>(responder.getAccount()) {
+            @Override
+            public void onResponse(ParsedResponse<List<FullBoard>> response) {
+                String etag = response.getHeaders().get("ETag");
+                if (etag != null && !etag.equals(account.getBoardsEtag())) {
+                    account.setBoardsEtag(etag);
+                    dataBaseAdapter.updateAccount(account);
+                }
+                responder.onResponse(response.getResponse());
+            }
+
+            @SuppressLint("MissingSuperCall")
+            @Override
+            public void onError(Throwable throwable) {
+                responder.onError(throwable);
+            }
+        });
     }
 
     @Override
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/CardDataProvider.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/CardDataProvider.java
index 15b8b2b74..0ceac2cd8 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/CardDataProvider.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/CardDataProvider.java
@@ -1,5 +1,7 @@
 package it.niedermann.nextcloud.deck.persistence.sync.helpers.providers;
 
+import android.annotation.SuppressLint;
+
 import java.time.Instant;
 import java.util.ArrayList;
 import java.util.Collections;
@@ -7,6 +9,7 @@ import java.util.List;
 
 import it.niedermann.nextcloud.deck.DeckLog;
 import it.niedermann.nextcloud.deck.api.IResponseCallback;
+import it.niedermann.nextcloud.deck.exceptions.DeckException;
 import it.niedermann.nextcloud.deck.exceptions.OfflineException;
 import it.niedermann.nextcloud.deck.model.Account;
 import it.niedermann.nextcloud.deck.model.Attachment;
@@ -54,6 +57,7 @@ public class CardDataProvider extends AbstractSyncDataProvider<FullCard> {
                     }
                 }
 
+                @SuppressLint("MissingSuperCall")
                 @Override
                 public void onError(Throwable throwable) {
                     responder.onError(throwable);
@@ -149,10 +153,14 @@ public class CardDataProvider extends AbstractSyncDataProvider<FullCard> {
 
     @Override
     public void createOnServer(ServerAdapter serverAdapter, DataBaseAdapter dataBaseAdapter, long accountId, IResponseCallback<FullCard> responder, FullCard entity) {
+        if (stack.getId() == null) {
+            responder.onError(new DeckException(DeckException.Hint.DEPENDENCY_NOT_SYNCED_YET, "Stack \"" +
+                    stack.getStack().getTitle() + "\" for Card \"" + entity.getCard().getTitle() +
+                    "\" is not synced yet. Perform a full sync (pull to refresh) as soon as you are online again."));
+            return;
+        }
         entity.getCard().setStackId(stack.getId());
-//        if (board != null && stack != null && board.getId() != null && stack.getId() != null) {
         serverAdapter.createCard(board.getId(), stack.getId(), entity.getCard(), responder);
-//        } else DeckLog.error("Skipped card creation due to missing remote ID");
     }
 
     @Override
@@ -323,6 +331,7 @@ public class CardDataProvider extends AbstractSyncDataProvider<FullCard> {
                         // do not delete, it's still there and was just moved!
                     }
 
+                    @SuppressLint("MissingSuperCall")
                     @Override
                     public void onError(Throwable throwable) {
                         if (!(throwable instanceof OfflineException)) {
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/StackDataProvider.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/StackDataProvider.java
index 6a8e1f227..93761d616 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/StackDataProvider.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/StackDataProvider.java
@@ -7,6 +7,7 @@ import java.util.Set;
 import java.util.concurrent.ConcurrentSkipListSet;
 
 import it.niedermann.nextcloud.deck.api.IResponseCallback;
+import it.niedermann.nextcloud.deck.exceptions.DeckException;
 import it.niedermann.nextcloud.deck.model.Board;
 import it.niedermann.nextcloud.deck.model.Card;
 import it.niedermann.nextcloud.deck.model.full.FullBoard;
@@ -74,6 +75,9 @@ public class StackDataProvider extends AbstractSyncDataProvider<FullStack> {
 
     @Override
     public void createOnServer(ServerAdapter serverAdapter, DataBaseAdapter dataBaseAdapter, long accountId, IResponseCallback<FullStack> responder, FullStack entity) {
+        if (board.getId() == null) {
+            throw new DeckException(DeckException.Hint.DEPENDENCY_NOT_SYNCED_YET, "Board for this stack is not synced yet. Perform a full sync (pull to referesh) as soon as you are online again.");
+        }
         entity.getStack().setBoardId(board.getId());
         serverAdapter.createStack(board.getBoard(), entity.getStack(), responder);
     }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/MainActivity.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/MainActivity.java
index 91c08ffad..5056985fa 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/MainActivity.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/MainActivity.java
@@ -470,21 +470,23 @@ public class MainActivity extends BrandedActivity implements DeleteStackListener
     }
 
     @Override
-    public void onCreateBoard(String title, String color) {
+    public void onCreateBoard(String title, @ColorInt int color) {
         if (boardsLiveData == null || boardsLiveDataObserver == null) {
             throw new IllegalStateException("Cannot create board when noone observe boards yet. boardsLiveData or observer is null.");
         }
         boardsLiveData.removeObserver(boardsLiveDataObserver);
-        final Board boardToCreate = new Board(title, color.startsWith("#") ? color.substring(1) : color);
+        final Board boardToCreate = new Board(title, color);
         boardToCreate.setPermissionEdit(true);
         boardToCreate.setPermissionManage(true);
-        observeOnce(syncManager.createBoard(mainViewModel.getCurrentAccount().getId(), boardToCreate), this, createdBoard -> {
-            if (createdBoard == null) {
-                BrandedSnackbar.make(binding.coordinatorLayout, "Open Deck in web interface first!", Snackbar.LENGTH_LONG)
-                        // TODO implement action!
-                        // .setAction(R.string.simple_open, v -> ExceptionDialogFragment.newInstance(throwable).show(getSupportFragmentManager(), ExceptionDialogFragment.class.getSimpleName()))
+
+        final WrappedLiveData<FullBoard> createLiveData = syncManager.createBoard(mainViewModel.getCurrentAccount().getId(), boardToCreate);
+        observeOnce(createLiveData, this, (createdBoard) -> {
+            if (createLiveData.hasError()) {
+                BrandedSnackbar.make(binding.coordinatorLayout, R.string.synchronization_failed, Snackbar.LENGTH_LONG)
+                        .setAction(R.string.simple_more, v -> ExceptionDialogFragment.newInstance(createLiveData.getError(), mainViewModel.getCurrentAccount()).show(getSupportFragmentManager(), ExceptionDialogFragment.class.getSimpleName()))
                         .show();
-            } else {
+            }
+            if (createdBoard != null && !createLiveData.hasError()) {
                 boardsList.add(createdBoard.getBoard());
                 setCurrentBoard(createdBoard.getBoard());
 
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/archivedboards/ArchivedBoardViewHolder.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/archivedboards/ArchivedBoardViewHolder.java
index 67b2c00be..30f1e5d49 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/archivedboards/ArchivedBoardViewHolder.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/archivedboards/ArchivedBoardViewHolder.java
@@ -6,6 +6,7 @@ import android.view.MenuItem;
 import android.view.View;
 
 import androidx.appcompat.widget.PopupMenu;
+import androidx.core.content.ContextCompat;
 import androidx.core.util.Consumer;
 import androidx.fragment.app.FragmentManager;
 import androidx.recyclerview.widget.RecyclerView;
@@ -30,14 +31,13 @@ public class ArchivedBoardViewHolder extends RecyclerView.ViewHolder {
 
     void bind(boolean isSupportedVersion, Board board, FragmentManager fragmentManager, Consumer<Board> dearchiveBoardListener) {
         final Context context = itemView.getContext();
-        binding.boardIcon.setImageDrawable(ViewUtil.getTintedImageView(binding.boardIcon.getContext(), R.drawable.circle_grey600_36dp, String.format("#%06X", (0xFFFFFF & board.getColor()))));
+        binding.boardIcon.setImageDrawable(ViewUtil.getTintedImageView(binding.boardIcon.getContext(), R.drawable.circle_grey600_36dp, board.getColor()));
         binding.boardMenu.setVisibility(View.GONE);
         binding.boardTitle.setText(board.getTitle());
         if (isSupportedVersion) {
             if (board.isPermissionManage()) {
                 binding.boardMenu.setVisibility(View.VISIBLE);
-                binding.boardMenu.setImageDrawable(ViewUtil.getTintedImageView(context, R.drawable.ic_menu, R.color.grey600));
-
+                binding.boardMenu.setImageDrawable(ViewUtil.getTintedImageView(context, R.drawable.ic_menu, ContextCompat.getColor(context, R.color.grey600)));
                 binding.boardMenu.setOnClickListener((v) -> {
                     PopupMenu popup = new PopupMenu(context, binding.boardMenu);
                     popup.getMenuInflater().inflate(R.menu.archived_board_menu, popup.getMenu());
@@ -47,28 +47,27 @@ public class ArchivedBoardViewHolder extends RecyclerView.ViewHolder {
                     }
                     popup.setOnMenuItemClickListener((MenuItem item) -> {
                         final String editBoard = context.getString(R.string.edit_board);
-                        switch (item.getItemId()) {
-                            case SHARE_BOARD_ID:
-                                AccessControlDialogFragment.newInstance(board.getLocalId()).show(fragmentManager, AccessControlDialogFragment.class.getSimpleName());
-                                return true;
-                            case R.id.edit_board:
-                                EditBoardDialogFragment.newInstance(board.getLocalId()).show(fragmentManager, editBoard);
-                                return true;
-                            case R.id.dearchive_board:
-                                dearchiveBoardListener.accept(board);
-                                return true;
-                            case R.id.delete_board:
-                                DeleteBoardDialogFragment.newInstance(board).show(fragmentManager, DeleteBoardDialogFragment.class.getSimpleName());
-                                return true;
-                            default:
-                                return false;
+                        int itemId = item.getItemId();
+                        if (itemId == SHARE_BOARD_ID) {
+                            AccessControlDialogFragment.newInstance(board.getLocalId()).show(fragmentManager, AccessControlDialogFragment.class.getSimpleName());
+                            return true;
+                        } else if (itemId == R.id.edit_board) {
+                            EditBoardDialogFragment.newInstance(board.getLocalId()).show(fragmentManager, editBoard);
+                            return true;
+                        } else if (itemId == R.id.dearchive_board) {
+                            dearchiveBoardListener.accept(board);
+                            return true;
+                        } else if (itemId == R.id.delete_board) {
+                            DeleteBoardDialogFragment.newInstance(board).show(fragmentManager, DeleteBoardDialogFragment.class.getSimpleName());
+                            return true;
                         }
+                        return false;
                     });
                     popup.show();
                 });
             } else if (board.isPermissionShare()) {
                 binding.boardMenu.setVisibility(View.VISIBLE);
-                binding.boardMenu.setImageDrawable(ViewUtil.getTintedImageView(context, R.drawable.ic_share_grey600_18dp, R.color.grey600));
+                binding.boardMenu.setImageDrawable(ViewUtil.getTintedImageView(context, R.drawable.ic_share_grey600_18dp, ContextCompat.getColor(context, R.color.grey600)));
                 binding.boardMenu.setOnClickListener((v) -> AccessControlDialogFragment.newInstance(board.getLocalId()).show(fragmentManager, AccessControlDialogFragment.class.getSimpleName()));
             }
             binding.boardMenu.setVisibility(View.VISIBLE);
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/board/BoardAdapter.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/board/BoardAdapter.java
index 5975e0306..c9501ffa9 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/board/BoardAdapter.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/board/BoardAdapter.java
@@ -37,7 +37,7 @@ public class BoardAdapter extends ArrayAdapter<Board> {
         TextView boardName = convertView.findViewById(R.id.boardName);
         if (board != null) {
             boardName.setText(board.getTitle());
-            boardName.setCompoundDrawables(ViewUtil.getTintedImageView(context, R.drawable.circle_grey600_36dp, String.format("#%06X", (0xFFFFFF & board.getColor()))), null, null, null);
+            boardName.setCompoundDrawables(ViewUtil.getTintedImageView(context, R.drawable.circle_grey600_36dp, board.getColor()), null, null, null);
         } else {
             DeckLog.logError(new IllegalArgumentException("board at position " + position + "is null"));
         }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/board/EditBoardDialogFragment.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/board/EditBoardDialogFragment.java
index e197727d5..1ee23abfa 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/board/EditBoardDialogFragment.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/board/EditBoardDialogFragment.java
@@ -56,7 +56,7 @@ public class EditBoardDialogFragment extends BrandedDialogFragment {
             dialogBuilder.setPositiveButton(R.string.simple_save, (dialog, which) -> {
                 this.fullBoard.board.setColor(binding.colorChooser.getSelectedColor());
                 this.fullBoard.board.setTitle(binding.input.getText().toString());
-                editBoardListener.onUpdateBoard(fullBoard);
+                this.editBoardListener.onUpdateBoard(fullBoard);
             });
             final MainViewModel viewModel = new ViewModelProvider(requireActivity()).get(MainViewModel.class);
             new SyncManager(requireActivity()).getFullBoardById(viewModel.getCurrentAccount().getId(), args.getLong(KEY_BOARD_ID)).observe(EditBoardDialogFragment.this, (FullBoard fb) -> {
@@ -65,13 +65,13 @@ public class EditBoardDialogFragment extends BrandedDialogFragment {
                     String title = this.fullBoard.getBoard().getTitle();
                     binding.input.setText(title);
                     binding.input.setSelection(title.length());
-                    binding.colorChooser.selectColor(String.format("#%06X", (0xFFFFFF & fullBoard.getBoard().getColor())));
+                    binding.colorChooser.selectColor(fullBoard.getBoard().getColor());
                 }
             });
         } else {
             dialogBuilder.setTitle(R.string.add_board);
             dialogBuilder.setPositiveButton(R.string.simple_add, (dialog, which) -> editBoardListener.onCreateBoard(binding.input.getText().toString(), binding.colorChooser.getSelectedColor()));
-            binding.colorChooser.selectColor(String.format("#%06X", 0xFFFFFF & ContextCompat.getColor(requireContext(), R.color.board_default_color)));
+            binding.colorChooser.selectColor(ContextCompat.getColor(requireContext(), R.color.board_default_color));
         }
 
         return dialogBuilder
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/board/EditBoardListener.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/board/EditBoardListener.java
index ee9ba9b9d..9d8fcdbde 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/board/EditBoardListener.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/board/EditBoardListener.java
@@ -1,11 +1,13 @@
 package it.niedermann.nextcloud.deck.ui.board;
 
+import androidx.annotation.ColorInt;
+
 import it.niedermann.nextcloud.deck.model.full.FullBoard;
 
 public interface EditBoardListener {
     void onUpdateBoard(FullBoard fullBoard);
 
-    default void onCreateBoard(String title, String color) {
+    default void onCreateBoard(String title, @ColorInt int color) {
         // Creating board is not necessary
     }
 }
\ No newline at end of file
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/board/managelabels/EditLabelDialogFragment.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/board/managelabels/EditLabelDialogFragment.java
index a0fb4cadd..2dacfe6ac 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/board/managelabels/EditLabelDialogFragment.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/board/managelabels/EditLabelDialogFragment.java
@@ -65,7 +65,7 @@ public class EditLabelDialogFragment extends BrandedDialogFragment {
         String title = this.label.getTitle();
         binding.input.setText(title);
         binding.input.setSelection(title.length());
-        binding.colorChooser.selectColor(String.format("#%06X", (0xFFFFFF & this.label.getColor())));
+        binding.colorChooser.selectColor(this.label.getColor());
 
         return dialogBuilder
                 .setView(binding.getRoot())
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/preparecreate/BoardAdapter.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/preparecreate/BoardAdapter.java
index 558a22db4..c27fa04ee 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/preparecreate/BoardAdapter.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/preparecreate/BoardAdapter.java
@@ -37,7 +37,7 @@ public class BoardAdapter extends AbstractAdapter<Board> {
         final Board item = getItem(position);
         if (item != null) {
             binding.boardTitle.setText(item.getTitle());
-            binding.avatar.setImageDrawable(ViewUtil.getTintedImageView(binding.avatar.getContext(), R.drawable.circle_grey600_36dp, String.format("#%06X", (0xFFFFFF & item.getColor()))));
+            binding.avatar.setImageDrawable(ViewUtil.getTintedImageView(binding.avatar.getContext(), R.drawable.circle_grey600_36dp, item.getColor()));
         } else {
             DeckLog.logError(new IllegalArgumentException("No item for position " + position));
         }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/view/ColorChooser.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/view/ColorChooser.java
index c82f47c9c..0dd431ff9 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/view/ColorChooser.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/view/ColorChooser.java
@@ -2,6 +2,7 @@ package it.niedermann.nextcloud.deck.ui.view;
 
 import android.content.Context;
 import android.content.res.TypedArray;
+import android.graphics.Color;
 import android.util.AttributeSet;
 import android.view.LayoutInflater;
 import android.view.View;
@@ -9,11 +10,15 @@ import android.view.ViewGroup;
 import android.widget.ImageView;
 import android.widget.LinearLayout;
 
+import androidx.annotation.ColorInt;
 import androidx.annotation.Nullable;
+import androidx.core.content.ContextCompat;
 
 import com.google.android.flexbox.FlexboxLayout;
 import com.skydoves.colorpickerview.listeners.ColorEnvelopeListener;
 
+import java.util.Arrays;
+
 import it.niedermann.android.util.DimensionUtil;
 import it.niedermann.nextcloud.deck.R;
 import it.niedermann.nextcloud.deck.databinding.WidgetColorChooserBinding;
@@ -24,10 +29,12 @@ public class ColorChooser extends LinearLayout {
     private final WidgetColorChooserBinding binding;
 
     private final Context context;
-    private final String[] colors;
+    private final int[] colors;
 
-    private String selectedColor;
-    private String previouslySelectedColor;
+    @ColorInt
+    private int selectedColor;
+    @ColorInt
+    private int previouslySelectedColor;
     @Nullable
     private ImageView previouslySelectedImageView;
 
@@ -42,14 +49,15 @@ public class ColorChooser extends LinearLayout {
         params.setMargins(0, DimensionUtil.INSTANCE.dpToPx(context, R.dimen.spacer_1x), 0, 0);
         params.setFlexBasisPercent(.15f);
 
-        TypedArray a = context.obtainStyledAttributes(attrs,
-                R.styleable.ColorChooser, 0, 0);
-        colors = getResources().getStringArray(a.getResourceId(R.styleable.ColorChooser_colors, 0));
+        final TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.ColorChooser, 0, 0);
+        colors = Arrays.stream(getResources().getStringArray(a.getResourceId(R.styleable.ColorChooser_colors, 0)))
+                .mapToInt(Color::parseColor)
+                .toArray();
         a.recycle();
 
         binding = WidgetColorChooserBinding.inflate(LayoutInflater.from(context), this, true);
-        for (final String color : colors) {
-            ImageView image = new ImageView(getContext());
+        for (final int color : colors) {
+            final ImageView image = new ImageView(getContext());
             image.setLayoutParams(params);
             image.setOnClickListener((imageView) -> {
                 if (previouslySelectedImageView != null) { // null when first selection
@@ -59,7 +67,7 @@ public class ColorChooser extends LinearLayout {
                 selectedColor = color;
                 this.previouslySelectedColor = color;
                 this.previouslySelectedImageView = image;
-                binding.customColorChooser.setImageDrawable(ViewUtil.getTintedImageView(this.context, R.drawable.circle_alpha_colorize_36dp, R.color.board_default_custom_color));
+                binding.customColorChooser.setImageDrawable(ViewUtil.getTintedImageView(this.context, R.drawable.circle_alpha_colorize_36dp, ContextCompat.getColor(context, R.color.board_default_custom_color)));
                 binding.customColorPicker.setVisibility(View.GONE);
                 binding.brightnessSlide.setVisibility(View.GONE);
             });
@@ -82,19 +90,20 @@ public class ColorChooser extends LinearLayout {
                 previouslySelectedImageView.setImageDrawable(ViewUtil.getTintedImageView(this.context, R.drawable.circle_grey600_36dp, previouslySelectedColor));
                 previouslySelectedImageView = null;
             }
-            String customColor = "#" + envelope.getHexCode().substring(2);
+            @ColorInt
+            final int customColor = envelope.getColor();
             selectedColor = customColor;
             previouslySelectedColor = customColor;
             binding.customColorChooser.setImageDrawable(ViewUtil.getTintedImageView(context, R.drawable.circle_alpha_colorize_36dp, selectedColor));
         });
     }
 
-    public void selectColor(String newColor) {
+    public void selectColor(@ColorInt int newColor) {
         boolean newColorIsCustomColor = true;
         selectedColor = newColor;
         for (int i = 0; i < colors.length; i++) {
-            if (colors[i].equals(newColor)) {
-                binding.customColorChooser.setImageDrawable(ViewUtil.getTintedImageView(this.context, R.drawable.circle_alpha_colorize_36dp, R.color.board_default_custom_color));
+            if (colors[i] == newColor) {
+                binding.customColorChooser.setImageDrawable(ViewUtil.getTintedImageView(this.context, R.drawable.circle_alpha_colorize_36dp, ContextCompat.getColor(context, R.color.board_default_custom_color)));
                 binding.colorPicker.getChildAt(i).performClick();
                 newColorIsCustomColor = false;
                 break;
@@ -105,7 +114,8 @@ public class ColorChooser extends LinearLayout {
         }
     }
 
-    public String getSelectedColor() {
+    @ColorInt
+    public int getSelectedColor() {
         return this.selectedColor;
     }
 }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/widget/stack/StackWidgetConfigurationActivity.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/widget/stack/StackWidgetConfigurationActivity.java
index 6b86b50ba..771feabc2 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/widget/stack/StackWidgetConfigurationActivity.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/widget/stack/StackWidgetConfigurationActivity.java
@@ -7,6 +7,7 @@ import android.os.Bundle;
 import androidx.appcompat.app.ActionBar;
 
 import it.niedermann.nextcloud.deck.DeckLog;
+import it.niedermann.nextcloud.deck.R;
 import it.niedermann.nextcloud.deck.model.Account;
 import it.niedermann.nextcloud.deck.ui.PickStackActivity;
 
@@ -18,7 +19,7 @@ public class StackWidgetConfigurationActivity extends PickStackActivity {
         super.onCreate(savedInstanceState);
         final ActionBar actionBar = getSupportActionBar();
         if (actionBar != null) {
-            actionBar.setTitle("Add stack widget");
+            actionBar.setTitle(R.string.add_stack_widget);
         }
 
         setResult(RESULT_CANCELED);
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/util/DrawerMenuUtil.java b/app/src/main/java/it/niedermann/nextcloud/deck/util/DrawerMenuUtil.java
index 1f6490bf2..1a88bec97 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/util/DrawerMenuUtil.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/util/DrawerMenuUtil.java
@@ -7,6 +7,7 @@ import android.view.SubMenu;
 import androidx.annotation.NonNull;
 import androidx.appcompat.widget.AppCompatImageButton;
 import androidx.appcompat.widget.PopupMenu;
+import androidx.core.content.ContextCompat;
 import androidx.fragment.app.FragmentActivity;
 
 import java.util.List;
@@ -38,12 +39,12 @@ public class DrawerMenuUtil {
         SubMenu boardsMenu = menu.addSubMenu(R.string.simple_boards);
         int index = 0;
         for (Board board : boards) {
-            MenuItem m = boardsMenu.add(Menu.NONE, index++, Menu.NONE, board.getTitle()).setIcon(ViewUtil.getTintedImageView(context, R.drawable.circle_grey600_36dp, String.format("#%06X", (0xFFFFFF & board.getColor()))));
+            MenuItem m = boardsMenu.add(Menu.NONE, index++, Menu.NONE, board.getTitle()).setIcon(ViewUtil.getTintedImageView(context, R.drawable.circle_grey600_36dp, board.getColor()));
             if (currentServerVersionIsSupported) {
                 if (board.isPermissionManage()) {
                     AppCompatImageButton contextMenu = new AppCompatImageButton(context);
                     contextMenu.setBackgroundDrawable(null);
-                    contextMenu.setImageDrawable(ViewUtil.getTintedImageView(context, R.drawable.ic_menu, R.color.grey600));
+                    contextMenu.setImageDrawable(ViewUtil.getTintedImageView(context, R.drawable.ic_menu, ContextCompat.getColor(context, R.color.grey600)));
                     contextMenu.setOnClickListener((v) -> {
                         PopupMenu popup = new PopupMenu(context, contextMenu);
                         popup.getMenuInflater().inflate(R.menu.navigation_context_menu, popup.getMenu());
@@ -53,28 +54,27 @@ public class DrawerMenuUtil {
                         }
                         popup.setOnMenuItemClickListener((MenuItem item) -> {
                             final String editBoard = context.getString(R.string.edit_board);
-                            switch (item.getItemId()) {
-                                case SHARE_BOARD_ID:
-                                    AccessControlDialogFragment.newInstance(board.getLocalId()).show(context.getSupportFragmentManager(), AccessControlDialogFragment.class.getSimpleName());
-                                    return true;
-                                case R.id.edit_board:
-                                    EditBoardDialogFragment.newInstance(board.getLocalId()).show(context.getSupportFragmentManager(), editBoard);
-                                    return true;
-                                case R.id.manage_labels:
-                                    ManageLabelsDialogFragment.newInstance(board.getLocalId()).show(context.getSupportFragmentManager(), editBoard);
-                                    return true;
-                                case R.id.clone_board:
-                                    context.onClone(board);
-                                    return true;
-                                case R.id.archive_board:
-                                    context.onArchive(board);
-                                    return true;
-                                case R.id.delete_board:
-                                    DeleteBoardDialogFragment.newInstance(board).show(context.getSupportFragmentManager(), DeleteBoardDialogFragment.class.getCanonicalName());
-                                    return true;
-                                default:
-                                    return false;
+                            int itemId = item.getItemId();
+                            if (itemId == SHARE_BOARD_ID) {
+                                AccessControlDialogFragment.newInstance(board.getLocalId()).show(context.getSupportFragmentManager(), AccessControlDialogFragment.class.getSimpleName());
+                                return true;
+                            } else if (itemId == R.id.edit_board) {
+                                EditBoardDialogFragment.newInstance(board.getLocalId()).show(context.getSupportFragmentManager(), editBoard);
+                                return true;
+                            } else if (itemId == R.id.manage_labels) {
+                                ManageLabelsDialogFragment.newInstance(board.getLocalId()).show(context.getSupportFragmentManager(), editBoard);
+                                return true;
+                            } else if (itemId == R.id.clone_board) {
+                                context.onClone(board);
+                                return true;
+                            } else if (itemId == R.id.archive_board) {
+                                context.onArchive(board);
+                                return true;
+                            } else if (itemId == R.id.delete_board) {
+                                DeleteBoardDialogFragment.newInstance(board).show(context.getSupportFragmentManager(), DeleteBoardDialogFragment.class.getCanonicalName());
+                                return true;
                             }
+                            return false;
                         });
                         popup.show();
                     });
@@ -82,7 +82,7 @@ public class DrawerMenuUtil {
                 } else if (board.isPermissionShare()) {
                     AppCompatImageButton contextMenu = new AppCompatImageButton(context);
                     contextMenu.setBackgroundDrawable(null);
-                    contextMenu.setImageDrawable(ViewUtil.getTintedImageView(context, R.drawable.ic_share_grey600_18dp, R.color.grey600));
+                    contextMenu.setImageDrawable(ViewUtil.getTintedImageView(context, R.drawable.ic_share_grey600_18dp, ContextCompat.getColor(context, R.color.grey600)));
                     contextMenu.setOnClickListener((v) -> AccessControlDialogFragment.newInstance(board.getLocalId()).show(context.getSupportFragmentManager(), AccessControlDialogFragment.class.getSimpleName()));
                     m.setActionView(contextMenu);
                 }
@@ -90,7 +90,7 @@ public class DrawerMenuUtil {
         }
 
         if (hasArchivedBoards) {
-            boardsMenu.add(Menu.NONE, MENU_ID_ARCHIVED_BOARDS, Menu.NONE, R.string.archived_boards).setIcon(ViewUtil.getTintedImageView(context, R.drawable.ic_archive_white_24dp, R.color.grey600));
+            boardsMenu.add(Menu.NONE, MENU_ID_ARCHIVED_BOARDS, Menu.NONE, R.string.archived_boards).setIcon(ViewUtil.getTintedImageView(context, R.drawable.ic_archive_white_24dp, ContextCompat.getColor(context, R.color.grey600)));
         }
 
         if (currentServerVersionIsSupported) {
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/util/ProjectUtil.java b/app/src/main/java/it/niedermann/nextcloud/deck/util/ProjectUtil.java
index f43f7d824..58c465290 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/util/ProjectUtil.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/util/ProjectUtil.java
@@ -33,7 +33,7 @@ public class ProjectUtil {
 
     /**
      * extracts the values of board- and card-ID from url.
-     * Depending on what kind of url it gets, it will return a long[] of lenght 1 or 2:
+     * Depending on what kind of url it gets, it will return a long[] of length 1 or 2:
      * If the url contains both values, you'll get 2, if it contains only the board, you'll get 1.
      * <p>
      * The order is fixed here: [boardId, cardId]
@@ -50,7 +50,7 @@ public class ProjectUtil {
             throw new IllegalArgumentException("trimmed url is empty");
         }
         // extract important part
-        String[] splitByPrefix = url.split(".*index\\.php/apps/deck(/#)?/board/");
+        String[] splitByPrefix = url.split(".*(index\\.php/)?apps/deck(/#)?/board/");
         // split into board- and card part
         if (splitByPrefix.length < 2) {
             throw new IllegalArgumentException("This URL doesn't seem to be an URL containing the boardId: \"" + url + "\"");
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/util/ViewUtil.java b/app/src/main/java/it/niedermann/nextcloud/deck/util/ViewUtil.java
index ffc06e33d..7319f7793 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/util/ViewUtil.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/util/ViewUtil.java
@@ -3,7 +3,6 @@ package it.niedermann.nextcloud.deck.util;
 import android.content.Context;
 import android.content.res.ColorStateList;
 import android.graphics.Bitmap;
-import android.graphics.Color;
 import android.graphics.drawable.Drawable;
 import android.net.Uri;
 import android.text.Spannable;
@@ -12,6 +11,7 @@ import android.text.style.ImageSpan;
 import android.widget.ImageView;
 import android.widget.TextView;
 
+import androidx.annotation.ColorInt;
 import androidx.annotation.ColorRes;
 import androidx.annotation.DrawableRes;
 import androidx.annotation.NonNull;
@@ -81,18 +81,14 @@ public final class ViewUtil {
         TextViewCompat.setCompoundDrawableTintList(cardDueDate, ColorStateList.valueOf(ContextCompat.getColor(context, textColor)));
     }
 
-    public static Drawable getTintedImageView(@NonNull Context context, @DrawableRes int imageId, @NonNull String color) {
+    public static Drawable getTintedImageView(@NonNull Context context, @DrawableRes int imageId, @ColorInt int color) {
         final Drawable drawable = ContextCompat.getDrawable(context, imageId);
         assert drawable != null;
         final Drawable wrapped = DrawableCompat.wrap(drawable).mutate();
-        DrawableCompat.setTint(wrapped, Color.parseColor(color));
+        DrawableCompat.setTint(wrapped, color);
         return drawable;
     }
 
-    public static Drawable getTintedImageView(@NonNull Context context, @DrawableRes int imageId, int colorId) {
-        return getTintedImageView(context, imageId, context.getResources().getString(colorId));
-    }
-
     /**
      * Replaces all mentions in the textView with an avatar and the display name
      *