Refactor attachment viewer to own activity with transition animation

12 files changed, 158 insertions, 424 deletions

diff --git a/app/src/main/AndroidManifest.xml b/app/src/main/AndroidManifest.xml
index 727b1df58..1433653a4 100644
--- a/app/src/main/AndroidManifest.xml
+++ b/app/src/main/AndroidManifest.xml
@@ -48,8 +48,7 @@
 
         <activity
             android:name=".ui.AttachmentsActivity"
-            android:label="@string/attachments"
-            android:theme="@style/AppTheme"
+            android:theme="@style/TransparentTheme"
             android:parentActivityName="it.niedermann.nextcloud.deck.ui.EditActivity" />
 
         <activity
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/AttachmentsActivity.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/AttachmentsActivity.java
index 5ec231351..411acdb90 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/AttachmentsActivity.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/AttachmentsActivity.java
@@ -1,90 +1,36 @@
 package it.niedermann.nextcloud.deck.ui;
 
-import android.content.SharedPreferences;
 import android.os.Bundle;
-import android.preference.PreferenceManager;
-import android.text.Editable;
-import android.text.TextWatcher;
-import android.view.Menu;
-import android.view.MenuInflater;
-import android.view.MenuItem;
-import android.view.View;
-import android.view.WindowManager;
-import android.widget.AdapterView;
-import android.widget.SpinnerAdapter;
+import android.view.MotionEvent;
 
-import androidx.appcompat.app.AlertDialog;
 import androidx.appcompat.app.AppCompatActivity;
 
-import com.google.android.material.tabs.TabLayout;
-import com.google.android.material.tabs.TabLayoutMediator;
-import com.nextcloud.android.sso.exceptions.NextcloudFilesAppAccountNotFoundException;
-import com.nextcloud.android.sso.exceptions.NoCurrentAccountSelectedException;
-import com.nextcloud.android.sso.helper.SingleAccountHelper;
-import com.nextcloud.android.sso.model.SingleSignOnAccount;
+import com.bumptech.glide.Glide;
 
-import java.util.ArrayList;
-import java.util.Date;
 import java.util.List;
 
-import it.niedermann.nextcloud.deck.Application;
 import it.niedermann.nextcloud.deck.DeckLog;
-import it.niedermann.nextcloud.deck.R;
-import it.niedermann.nextcloud.deck.databinding.ActivityEditBinding;
-import it.niedermann.nextcloud.deck.model.Account;
-import it.niedermann.nextcloud.deck.model.Board;
-import it.niedermann.nextcloud.deck.model.Card;
-import it.niedermann.nextcloud.deck.model.Label;
-import it.niedermann.nextcloud.deck.model.User;
-import it.niedermann.nextcloud.deck.model.full.FullCard;
+import it.niedermann.nextcloud.deck.databinding.ActivityAttachmentsBinding;
+import it.niedermann.nextcloud.deck.model.Attachment;
 import it.niedermann.nextcloud.deck.persistence.sync.SyncManager;
-import it.niedermann.nextcloud.deck.ui.board.BoardAdapter;
-import it.niedermann.nextcloud.deck.ui.card.CardDetailsFragment;
-import it.niedermann.nextcloud.deck.ui.card.CardTabAdapter;
-import it.niedermann.nextcloud.deck.ui.card.CommentDialogFragment;
 import it.niedermann.nextcloud.deck.ui.exception.ExceptionHandler;
-import it.niedermann.nextcloud.deck.util.CardUtil;
+import it.niedermann.nextcloud.deck.util.AttachmentUtil;
 
-import static it.niedermann.nextcloud.deck.persistence.sync.adapters.db.util.LiveDataHelper.observeOnce;
 import static it.niedermann.nextcloud.deck.ui.card.CardAdapter.BUNDLE_KEY_ACCOUNT_ID;
-import static it.niedermann.nextcloud.deck.ui.card.CardAdapter.BUNDLE_KEY_BOARD_ID;
 import static it.niedermann.nextcloud.deck.ui.card.CardAdapter.BUNDLE_KEY_LOCAL_ID;
-import static it.niedermann.nextcloud.deck.ui.card.CardAdapter.BUNDLE_KEY_STACK_ID;
-import static it.niedermann.nextcloud.deck.ui.card.CardAdapter.NO_LOCAL_ID;
 
-public class AttachmentsActivity extends AppCompatActivity implements
-        CardDetailsFragment.CardDetailsListener,
-        CommentDialogFragment.AddCommentListener,
-        AdapterView.OnItemSelectedListener {
+public class AttachmentsActivity extends AppCompatActivity {
 
-    private ActivityEditBinding binding;
-    private SyncManager syncManager;
+    private ActivityAttachmentsBinding binding;
 
-    private static final int[] tabTitles = new int[]{
-            R.string.card_edit_details,
-            R.string.card_edit_attachments,
-            R.string.card_edit_activity
-    };
-
-    private FullCard originalCard;
-    private FullCard fullCard;
-
-    private long accountId;
-    private long boardId;
-    private long stackId;
-    private long localId;
-
-    private boolean pendingCreation = false;
-    private boolean canEdit;
-    private boolean createMode;
+    public static final String BUNDLE_KEY_CURRENT_ATTACHMENT_LOCAL_ID = "currentAttachmenLocaltId";
 
     @Override
     public void onCreate(Bundle savedInstanceState) {
-        setTheme(Application.getAppTheme(this) ? R.style.DarkAppTheme : R.style.AppTheme);
         super.onCreate(savedInstanceState);
         Thread.currentThread().setUncaughtExceptionHandler(new ExceptionHandler(this));
 
-        binding = ActivityEditBinding.inflate(getLayoutInflater());
+        binding = ActivityAttachmentsBinding.inflate(getLayoutInflater());
         setContentView(binding.getRoot());
 
         setSupportActionBar(binding.toolbar);
@@ -93,253 +39,50 @@ public class AttachmentsActivity extends AppCompatActivity implements
         if (extras == null) {
             throw new IllegalArgumentException("Provide localId");
         }
-        accountId = extras.getLong(BUNDLE_KEY_ACCOUNT_ID);
-        boardId = extras.getLong(BUNDLE_KEY_BOARD_ID);
-        stackId = extras.getLong(BUNDLE_KEY_STACK_ID);
-        localId = extras.getLong(BUNDLE_KEY_LOCAL_ID);
-        syncManager = new SyncManager(this);
-
-        createMode = NO_LOCAL_ID.equals(localId);
-        if (boardId == 0L) {
-            try {
-                createMode = true;
-                SingleSignOnAccount ssoa = SingleAccountHelper.getCurrentSingleSignOnAccount(this);
-                syncManager.readAccount(ssoa.name).observe(this, (Account account) -> {
-                    accountId = account.getId();
-                    binding.selectBoardWrapper.setVisibility(View.VISIBLE);
-                    syncManager.getBoards(account.getId()).observe(this, (List<Board> boardsList) -> {
-                        for (Board board : boardsList) {
-                            if (!board.isPermissionEdit()) {
-                                boardsList.remove(board);
-                            }
-                        }
-                        Board[] boardsArray = new Board[boardsList.size()];
-                        boardsArray = boardsList.toArray(boardsArray);
-                        SpinnerAdapter adapter = new BoardAdapter(this, boardsArray);
-                        binding.boardSelector.setAdapter(adapter);
-
-                        SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(this);
-                        long lastBoardId = sharedPreferences.getLong(getString(R.string.shared_preference_last_board_for_account_) + accountId, 0L);
-                        DeckLog.log("--- Read: shared_preference_last_board_for_account_" + account.getId() + " | " + lastBoardId);
-                        if (lastBoardId != 0L) {
-                            for (int i = 0; i < boardsArray.length; i++) {
-                                if (boardsArray[i].getLocalId() == lastBoardId) {
-                                    binding.boardSelector.setSelection(i);
+        long accountId = extras.getLong(BUNDLE_KEY_ACCOUNT_ID);
+        long cardLocalId = extras.getLong(BUNDLE_KEY_LOCAL_ID);
+        long currentAttachment = extras.getLong(BUNDLE_KEY_CURRENT_ATTACHMENT_LOCAL_ID);
+
+        SyncManager syncManager = new SyncManager(this);
+
+        syncManager.readAccount(accountId).observe(this, account ->
+                syncManager.getCardByLocalId(accountId, cardLocalId).observe(this, fullCard -> {
+                    binding.toolbar.setSubtitle(fullCard.getCard().getTitle());
+                    List<Attachment> attachments = fullCard.getAttachments();
+                    if (fullCard.getAttachments().size() == 0) {
+                        DeckLog.logError(new IllegalStateException(AttachmentsActivity.class.getSimpleName() + " called, but card " + fullCard.getLocalId() + "has no attachments"));
+                        finish();
+                    } else {
+                        if (currentAttachment != 0L) {
+                            for (Attachment a : attachments) {
+                                if (a.getLocalId() == currentAttachment) {
+                                    Glide.with(this)
+                                            .load(AttachmentUtil.getUrl(account.getUrl(), fullCard.getId(), a.getId()))
+                                            .into(binding.image);
+                                    binding.toolbar.setTitle(a.getBasename());
+                                    break;
                                 }
                             }
+                        } else {
+                            DeckLog.logError(new IllegalStateException("No " + BUNDLE_KEY_CURRENT_ATTACHMENT_LOCAL_ID + " was provided. Falling back to displaying first image."));
+                            Glide.with(this)
+                                    .load(AttachmentUtil.getUrl(account.getUrl(), fullCard.getId(), attachments.get(0).getId()))
+                                    .into(binding.image);
+                            binding.toolbar.setTitle(attachments.get(0).getBasename());
                         }
-                        binding.boardSelector.setOnItemSelectedListener(this);
-                    });
-                });
-            } catch (NextcloudFilesAppAccountNotFoundException | NoCurrentAccountSelectedException e) {
-                e.printStackTrace();
-            }
-        } else {
-            if (accountId == 0L) {
-                throw new IllegalArgumentException("No accountId given");
-            }
-            observeOnce(syncManager.getFullBoardById(accountId, boardId), AttachmentsActivity.this, (fullBoard -> {
-                canEdit = fullBoard.getBoard().isPermissionEdit();
-                invalidateOptionsMenu();
-                if (createMode) {
-                    fullCard = new FullCard();
-                    originalCard = new FullCard();
-                    fullCard.setLabels(new ArrayList<>());
-                    fullCard.setAssignedUsers(new ArrayList<>());
-                    Card card = new Card();
-                    card.setStackId(stackId);
-                    fullCard.setCard(card);
-                    setupViewPager();
-                    setupTitle(createMode);
-                } else {
-                    observeOnce(syncManager.getCardByLocalId(accountId, localId), AttachmentsActivity.this, (next) -> {
-                        fullCard = next;
-                        originalCard = new FullCard(fullCard);
-                        setupViewPager();
-                        setupTitle(createMode);
-                    });
-                }
-            }));
-        }
-    }
-
-    @Override
-    public boolean onCreateOptionsMenu(Menu menu) {
-        if (canEdit) {
-            MenuInflater inflater = getMenuInflater();
-            inflater.inflate(R.menu.card_edit_menu, menu);
-        } else {
-            menu.clear();
-        }
-        return super.onCreateOptionsMenu(menu);
-    }
-
-    @Override
-    public boolean onOptionsItemSelected(MenuItem item) {
-        if (item.getItemId() == R.id.action_card_save) {
-            saveAndFinish();
-        }
-        return super.onOptionsItemSelected(item);
-    }
-
-    private void saveAndFinish() {
-        if (!pendingCreation) {
-            pendingCreation = true;
-            if (fullCard.getCard().getTitle() == null || fullCard.getCard().getTitle().isEmpty()) {
-                fullCard.getCard().setTitle(CardUtil.generateTitleFromDescription(fullCard.getCard().getDescription()));
-            }
-            if (fullCard.getCard().getTitle().isEmpty()) {
-                new AlertDialog.Builder(this)
-                        .setTitle("Title is mandatory")
-                        .setMessage("Provide at least a title or description")
-                        .setPositiveButton(android.R.string.ok, null)
-                        .setOnDismissListener(dialog -> {
-                            pendingCreation = false;
-                        })
-                        .show();
-            } else {
-                if (createMode) {
-                    observeOnce(syncManager.createFullCard(accountId, boardId, stackId, fullCard), AttachmentsActivity.this, (card) -> super.finish());
-                } else {
-                    observeOnce(syncManager.updateCard(fullCard), AttachmentsActivity.this, (card) -> super.finish());
-                }
-            }
-        }
-    }
-
-    private void setupViewPager() {
-        binding.tabLayout.removeAllTabs();
-        binding.tabLayout.setTabGravity(TabLayout.GRAVITY_FILL);
-        CardTabAdapter adapter = new CardTabAdapter(getSupportFragmentManager(), getLifecycle(), accountId, localId, boardId, canEdit);
-        binding.pager.setOffscreenPageLimit(2);
-        binding.pager.setAdapter(adapter);
-        new TabLayoutMediator(binding.tabLayout, binding.pager, (tab, position) -> tab.setText(tabTitles[position])).attach();
-    }
-
-    private void setupTitle(boolean createMode) {
-        binding.title.setText(fullCard.getCard().getTitle());
-        if (canEdit) {
-            if (createMode) {
-                binding.title.requestFocus();
-                getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_STATE_ALWAYS_VISIBLE);
-                if (fullCard.getCard().getTitle() != null) {
-                    binding.title.setSelection(fullCard.getCard().getTitle().length());
-                }
-            }
-            binding.titleTextInputLayout.setHint(getString(createMode ? R.string.simple_add : R.string.edit));
-            binding.title.addTextChangedListener(new TextWatcher() {
-                @Override
-                public void onTextChanged(CharSequence s, int start, int before, int count) {
-                    fullCard.getCard().setTitle(binding.title.getText().toString());
-                }
-
-                @Override
-                public void beforeTextChanged(CharSequence s, int start, int count, int after) {
-                }
-
-                @Override
-                public void afterTextChanged(Editable s) {
-                }
-            });
-        } else {
-            binding.titleTextInputLayout.setHintEnabled(false);
-            binding.title.setEnabled(false);
-        }
-    }
-
-    @Override
-    public void onDescriptionChanged(String description) {
-        this.fullCard.getCard().setDescription(description);
-    }
-
-    @Override
-    public void onUserAdded(User user) {
-        this.fullCard.getAssignedUsers().add(user);
-    }
-
-    @Override
-    public void onUserRemoved(User user) {
-        this.fullCard.getAssignedUsers().remove(user);
-    }
-
-    @Override
-    public void onLabelAdded(Label label) {
-        this.fullCard.getLabels().add(label);
-    }
-
-    @Override
-    public void onLabelRemoved(Label label) {
-        this.fullCard.getLabels().remove(label);
-    }
-
-    @Override
-    public void onDueDateChanged(Date dueDate) {
-        this.fullCard.getCard().setDueDate(dueDate);
-    }
-
-    @Override
-    public boolean onSupportNavigateUp() {
-        finish(); // close this activity as oppose to navigating up
-        return true;
-    }
-
-    @Override
-    public void onBackPressed() {
-        finish();
-    }
-
-    @Override
-    public void finish() {
-        if (!fullCard.equals(originalCard) && canEdit) {
-            new AlertDialog.Builder(this)
-                    .setTitle(R.string.simple_save)
-                    .setMessage(R.string.do_you_want_to_save_your_changes)
-                    .setPositiveButton(R.string.simple_save, (dialog, whichButton) -> saveAndFinish())
-                    .setNegativeButton(R.string.simple_discard, (dialog, whichButton) -> super.finish()).show();
-        } else {
-            super.finish();
-        }
-    }
-
-    @Override
-    public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
-        boardId = ((Board) binding.boardSelector.getItemAtPosition(position)).getLocalId();
-        observeOnce(syncManager.getFullBoardById(accountId, boardId), AttachmentsActivity.this, (fullBoard -> {
-            canEdit = fullBoard.getBoard().isPermissionEdit();
-
-            SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(this);
-            long savedStackId = sharedPreferences.getLong(getString(R.string.shared_preference_last_stack_for_account_and_board_) + accountId + "_" + boardId, 0L);
-            DeckLog.log("--- Read: shared_preference_last_stack_for_account_and_board" + accountId + "_" + boardId + " | " + savedStackId);
-            if (savedStackId == 0L) {
-                observeOnce(syncManager.getStacksForBoard(accountId, boardId), AttachmentsActivity.this, (stacks -> {
-                    if (stacks != null && stacks.size() > 0) {
-                        stackId = stacks.get(0).getLocalId();
                     }
                 }));
-            } else {
-                stackId = savedStackId;
-            }
-            if (fullCard == null) {
-                invalidateOptionsMenu();
-                fullCard = new FullCard();
-                fullCard.setLabels(new ArrayList<>());
-                fullCard.setAssignedUsers(new ArrayList<>());
-                Card card = new Card();
-                card.setStackId(stackId);
-                fullCard.setCard(card);
-                setupViewPager();
-                setupTitle(createMode);
-            }
-        }));
     }
 
     @Override
-    public void onNothingSelected(AdapterView<?> parent) {
-
+    public boolean onTouchEvent(MotionEvent event) {
+        supportFinishAfterTransition();
+        return true;
     }
 
     @Override
-    public void onCommentAdded(String comment) {
-        syncManager.addCommentToCard(accountId, boardId, localId, comment);
+    public boolean onSupportNavigateUp() {
+        supportFinishAfterTransition();
+        return true;
     }
 }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/AttachmentAdapter.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/AttachmentAdapter.java
index 1ea2c43e1..7cd953787 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/AttachmentAdapter.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/AttachmentAdapter.java
@@ -6,20 +6,22 @@ import android.content.ClipboardManager;
 import android.content.Context;
 import android.content.Intent;
 import android.net.Uri;
+import android.os.Build;
 import android.text.format.Formatter;
+import android.transition.Explode;
 import android.util.Log;
 import android.view.LayoutInflater;
+import android.view.MenuInflater;
 import android.view.View;
 import android.view.ViewGroup;
 import android.widget.ImageView;
 import android.widget.Toast;
 
 import androidx.annotation.NonNull;
-import androidx.appcompat.app.AppCompatActivity;
+import androidx.core.app.ActivityOptionsCompat;
 import androidx.recyclerview.widget.RecyclerView;
 
 import com.bumptech.glide.Glide;
-import com.bumptech.glide.load.resource.bitmap.CenterCrop;
 
 import java.util.List;
 
@@ -29,31 +31,40 @@ import it.niedermann.nextcloud.deck.databinding.ItemAttachmentImageBinding;
 import it.niedermann.nextcloud.deck.model.Account;
 import it.niedermann.nextcloud.deck.model.Attachment;
 import it.niedermann.nextcloud.deck.model.enums.DBStatus;
+import it.niedermann.nextcloud.deck.ui.AttachmentsActivity;
+import it.niedermann.nextcloud.deck.util.AttachmentUtil;
 import it.niedermann.nextcloud.deck.util.DateUtil;
 import it.niedermann.nextcloud.deck.util.DeleteDialogBuilder;
 
 import static android.content.Context.CLIPBOARD_SERVICE;
 import static androidx.constraintlayout.widget.Constraints.TAG;
+import static it.niedermann.nextcloud.deck.ui.AttachmentsActivity.BUNDLE_KEY_CURRENT_ATTACHMENT_LOCAL_ID;
+import static it.niedermann.nextcloud.deck.ui.card.CardAdapter.BUNDLE_KEY_ACCOUNT_ID;
+import static it.niedermann.nextcloud.deck.ui.card.CardAdapter.BUNDLE_KEY_LOCAL_ID;
 
 public class AttachmentAdapter extends RecyclerView.Adapter<AttachmentAdapter.AttachmentViewHolder> {
 
     public static final int VIEW_TYPE_DEFAULT = 2;
     public static final int VIEW_TYPE_IMAGE = 1;
 
+    private final MenuInflater menuInflator;
     private final Account account;
     private final long cardRemoteId;
+    private final long cardLocalId;
     @NonNull
     private List<Attachment> attachments;
     @NonNull
     private AttachmentDeletedListener attachmentDeletedListener;
     private Context context;
 
-    AttachmentAdapter(@NonNull AttachmentDeletedListener attachmentDeletedListener, @NonNull Account account, long cardRemoteId, @NonNull List<Attachment> attachments) {
+    AttachmentAdapter(@NonNull MenuInflater menuInflator, @NonNull AttachmentDeletedListener attachmentDeletedListener, @NonNull Account account, long cardLocalId, long cardRemoteId, @NonNull List<Attachment> attachments) {
         super();
+        this.menuInflator = menuInflator;
         this.attachmentDeletedListener = attachmentDeletedListener;
         this.attachments = attachments;
         this.account = account;
         this.cardRemoteId = cardRemoteId;
+        this.cardLocalId = cardLocalId;
     }
 
     @NonNull
@@ -75,10 +86,10 @@ public class AttachmentAdapter extends RecyclerView.Adapter<AttachmentAdapter.At
     public void onBindViewHolder(@NonNull AttachmentViewHolder holder, int position) {
         Attachment attachment = attachments.get(position);
         int viewType = getItemViewType(position);
-        String uri = account.getUrl() + "/index.php/apps/deck/cards/" + cardRemoteId + "/attachment/" + attachment.getId();
+        String uri = AttachmentUtil.getUrl(account.getUrl(), cardRemoteId, attachment.getId());
         holder.setNotSyncedYetStatus(attachment.getStatusEnum() == DBStatus.UP_TO_DATE);
         holder.getRootView().setOnCreateContextMenuListener((menu, v, menuInfo) -> {
-            ((Activity) context).getMenuInflater().inflate(R.menu.attachment_menu, menu);
+            menuInflator.inflate(R.menu.attachment_menu, menu);
             menu.findItem(R.id.delete).setOnMenuItemClickListener(item -> {
                 new DeleteDialogBuilder(context)
                         .setTitle(context.getString(R.string.delete_something, attachment.getFilename()))
@@ -89,7 +100,7 @@ public class AttachmentAdapter extends RecyclerView.Adapter<AttachmentAdapter.At
                 return false;
             });
             menu.findItem(android.R.id.copyUrl).setOnMenuItemClickListener(item -> {
-                final android.content.ClipboardManager clipboardManager = (ClipboardManager) context.getSystemService(CLIPBOARD_SERVICE);
+                final ClipboardManager clipboardManager = (ClipboardManager) context.getSystemService(CLIPBOARD_SERVICE);
                 ClipData clipData = ClipData.newPlainText(attachment.getFilename(), uri);
                 if (clipboardManager != null) {
                     clipboardManager.setPrimaryClip(clipData);
@@ -103,14 +114,24 @@ public class AttachmentAdapter extends RecyclerView.Adapter<AttachmentAdapter.At
 
         if (attachment.getMimetype() != null) {
             if (attachment.getMimetype().startsWith("image")) {
-                // TODO Glide is currently not yet able to use SSO and fails on authentication
                 Glide.with(context)
                         .load(uri)
-                        .transform(new CenterCrop())
                         .error(R.drawable.ic_image_grey600_24dp)
                         .into(holder.getPreview());
                 holder.getPreview().setImageResource(R.drawable.ic_image_grey600_24dp);
-                holder.getPreview().getRootView().setOnClickListener((v) -> AttachmentDialogFragment.newInstance(uri, attachment.getBasename()).show(((AppCompatActivity) context).getSupportFragmentManager(), "preview"));
+                holder.getPreview().getRootView().setOnClickListener((v) -> {
+                    Intent intent = new Intent(context, AttachmentsActivity.class);
+                    intent.putExtra(BUNDLE_KEY_ACCOUNT_ID, account.getId());
+                    intent.putExtra(BUNDLE_KEY_LOCAL_ID, cardLocalId);
+                    intent.putExtra(BUNDLE_KEY_CURRENT_ATTACHMENT_LOCAL_ID, attachment.getLocalId());
+                    intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
+                    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP && context instanceof Activity) {
+                        ((Activity) context).getWindow().setSharedElementEnterTransition(new Explode());
+                        context.startActivity(intent, ActivityOptionsCompat.makeSceneTransitionAnimation((Activity) context, holder.getPreview(), context.getString(R.string.transition_attachment_preview)).toBundle());
+                    } else {
+                        context.startActivity(intent);
+                    }
+                });
             } else if (attachment.getMimetype().startsWith("audio")) {
                 holder.getPreview().setImageResource(R.drawable.ic_music_note_grey600_24dp);
             } else if (attachment.getMimetype().startsWith("video")) {
@@ -127,8 +148,8 @@ public class AttachmentAdapter extends RecyclerView.Adapter<AttachmentAdapter.At
             default: {
                 DefaultAttachmentViewHolder defaultHolder = (DefaultAttachmentViewHolder) holder;
                 defaultHolder.binding.filename.getRootView().setOnClickListener((event) -> {
-                    Intent openURL = new Intent(android.content.Intent.ACTION_VIEW);
-                    openURL.setData(Uri.parse(account.getUrl() + "/index.php/apps/deck/cards/" + cardRemoteId + "/attachment/" + attachment.getId()));
+                    Intent openURL = new Intent(Intent.ACTION_VIEW);
+                    openURL.setData(Uri.parse(AttachmentUtil.getUrl(account.getUrl(), cardRemoteId, attachment.getId())));
                     context.startActivity(openURL);
                 });
                 defaultHolder.binding.filename.setText(attachment.getBasename());
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/AttachmentDialogFragment.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/AttachmentDialogFragment.java
deleted file mode 100644
index da2086d4c..000000000
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/AttachmentDialogFragment.java
+++ /dev/null
@@ -1,83 +0,0 @@
-package it.niedermann.nextcloud.deck.ui.card;
-
-import android.app.Dialog;
-import android.graphics.Color;
-import android.graphics.drawable.ColorDrawable;
-import android.os.Bundle;
-import android.view.LayoutInflater;
-import android.view.View;
-import android.view.ViewGroup;
-
-import androidx.annotation.NonNull;
-import androidx.annotation.Nullable;
-import androidx.appcompat.app.AlertDialog;
-import androidx.fragment.app.DialogFragment;
-
-import com.bumptech.glide.Glide;
-
-import java.util.Objects;
-
-import it.niedermann.nextcloud.deck.Application;
-import it.niedermann.nextcloud.deck.R;
-import it.niedermann.nextcloud.deck.databinding.DialogAttachmentBinding;
-
-public class AttachmentDialogFragment extends DialogFragment {
-
-    private static final String BUNDLE_KEY_URL = "url";
-    private static final String BUNDLE_KEY_ALT = "alt";
-
-    /**
-     * Use newInstance()-Method
-     */
-    public AttachmentDialogFragment() {
-    }
-
-    @NonNull
-    @Override
-    public Dialog onCreateDialog(Bundle savedInstanceState) {
-        DialogAttachmentBinding binding = DialogAttachmentBinding.inflate(requireActivity().getLayoutInflater());
-
-        Glide.with(this)
-//                .addDefaultRequestListener(new RequestListener<Object>() {
-//                    @Override
-//                    public boolean onLoadFailed(@Nullable GlideException e, Object model, Target<Object> target, boolean isFirstResource) {
-//                        image.setVisibility(View.VISIBLE);
-//                        progressBar.setVisibility(View.GONE);
-//                        return false;
-//                    }
-//
-//                    @Override
-//                    public boolean onResourceReady(Object resource, Object model, Target<Object> target, DataSource dataSource, boolean isFirstResource) {
-//                        progressBar.setVisibility(View.GONE);
-//                        image.setVisibility(View.VISIBLE);
-//                        return false;
-//                    }
-//                })
-                .load(requireArguments().getString(BUNDLE_KEY_URL))
-                .into(binding.image);
-        binding.image.setContentDescription(requireArguments().getString(BUNDLE_KEY_ALT));
-        binding.image.getRootView().setOnClickListener((v) -> dismiss());
-
-        return new AlertDialog.Builder(requireActivity(), Application.getAppTheme(getContext()) ? R.style.DialogDarkTheme : R.style.ThemeOverlay_AppCompat_Dialog_Alert)
-                .setView(binding.getRoot())
-                .create();
-    }
-
-    @Nullable
-    @Override
-    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
-        Objects.requireNonNull(requireDialog().getWindow()).setBackgroundDrawable(new ColorDrawable(Color.TRANSPARENT));
-        return super.onCreateView(inflater, container, savedInstanceState);
-    }
-
-    public static AttachmentDialogFragment newInstance(@NonNull String url, @NonNull String alt) {
-        Bundle bundle = new Bundle();
-        bundle.putString(BUNDLE_KEY_URL, url);
-        bundle.putString(BUNDLE_KEY_ALT, alt);
-
-        AttachmentDialogFragment fragment = new AttachmentDialogFragment();
-        fragment.setArguments(bundle);
-
-        return fragment;
-    }
-}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/CardAttachmentsFragment.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/CardAttachmentsFragment.java
index a8a126b67..33e5a6306 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/CardAttachmentsFragment.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/CardAttachmentsFragment.java
@@ -66,7 +66,13 @@ public class CardAttachmentsFragment extends Fragment implements AttachmentAdapt
                     this.binding.emptyContentView.setVisibility(View.GONE);
                     this.binding.attachmentsList.setVisibility(View.VISIBLE);
                     syncManager.readAccount(accountId).observe(getViewLifecycleOwner(), (Account account) -> {
-                        RecyclerView.Adapter adapter = new AttachmentAdapter(this, account, fullCard.getCard().getId(), fullCard.getAttachments());
+                        RecyclerView.Adapter adapter = new AttachmentAdapter(
+                                requireActivity().getMenuInflater(),
+                                this,
+                                account,
+                                fullCard.getCard().getLocalId(),
+                                fullCard.getCard().getId(),
+                                fullCard.getAttachments());
                         binding.attachmentsList.setAdapter(adapter);
                         GridLayoutManager glm = new GridLayoutManager(getActivity(), 3);
 
@@ -130,15 +136,13 @@ public class CardAttachmentsFragment extends Fragment implements AttachmentAdapt
     public void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
         super.onActivityResult(requestCode, resultCode, data);
         if (requestCode == REQUEST_CODE_ADD_ATTACHMENT && resultCode == Activity.RESULT_OK) {
-            Uri uri = null;
             if (data != null) {
-                uri = data.getData();
+                Uri uri = data.getData();
                 Log.i(TAG, "Uri: " + uri.toString());
                 String path = FileUtils.getPath(getContext(), uri);
                 File uploadFile = new File(path);
                 syncManager.addAttachmentToCard(accountId, cardId, Attachment.getMimetypeForUri(getContext(), uri), uploadFile);
             }
-
         }
     }
 
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/util/AttachmentUtil.java b/app/src/main/java/it/niedermann/nextcloud/deck/util/AttachmentUtil.java
new file mode 100644
index 000000000..d123ee4c6
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/util/AttachmentUtil.java
@@ -0,0 +1,15 @@
+package it.niedermann.nextcloud.deck.util;
+
+/**
+ * Created by stefan on 07.03.20.
+ */
+
+public class AttachmentUtil {
+
+    private AttachmentUtil() {
+    }
+
+    public static String getUrl(String accountUrl, long cardRemoteId, long attachmentRemoteId) {
+        return accountUrl + "/index.php/apps/deck/cards/" + cardRemoteId + "/attachment/" + attachmentRemoteId;
+    }
+}
diff --git a/app/src/main/res/layout/activity_attachments.xml b/app/src/main/res/layout/activity_attachments.xml
new file mode 100644
index 000000000..4d1fabe17
--- /dev/null
+++ b/app/src/main/res/layout/activity_attachments.xml
@@ -0,0 +1,36 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:orientation="vertical"
+    tools:theme="@style/TransparentTheme">
+
+    <com.google.android.material.appbar.AppBarLayout
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content">
+
+        <androidx.appcompat.widget.Toolbar
+            android:id="@+id/toolbar"
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            app:navigationIcon="@drawable/ic_arrow_back_white_24dp"
+            app:titleTextColor="@android:color/white"
+            tools:title="@string/attachments" />
+    </com.google.android.material.appbar.AppBarLayout>
+
+    <androidx.viewpager2.widget.ViewPager2
+        android:id="@+id/view_pager"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content" />
+
+    <androidx.appcompat.widget.AppCompatImageView
+        android:id="@+id/image"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        android:contentDescription="@null"
+        android:transitionName="@string/transition_attachment_preview"
+        tools:src="@drawable/ic_image_grey600_24dp"
+        tools:targetApi="lollipop" />
+</LinearLayout>
\ No newline at end of file
diff --git a/app/src/main/res/layout/dialog_attachment.xml b/app/src/main/res/layout/dialog_attachment.xml
deleted file mode 100644
index 4b3f96008..000000000
--- a/app/src/main/res/layout/dialog_attachment.xml
+++ /dev/null
@@ -1,18 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
-    android:layout_width="wrap_content"
-    android:layout_height="wrap_content">
-
-    <ImageView xmlns:tools="http://schemas.android.com/tools"
-        android:id="@+id/image"
-        android:layout_width="wrap_content"
-        android:layout_height="wrap_content"
-        android:contentDescription="@null"
-        tools:src="@drawable/ic_image_grey600_24dp" />
-
-    <!--    <ProgressBar-->
-    <!--        android:id="@+id/progressBar"-->
-    <!--        android:visibility="visible"-->
-    <!--        android:layout_width="wrap_content"-->
-    <!--        android:layout_height="wrap_content" />-->
-</FrameLayout>
\ No newline at end of file
diff --git a/app/src/main/res/layout/item_attachment_default.xml b/app/src/main/res/layout/item_attachment_default.xml
index f58783559..11d147d92 100644
--- a/app/src/main/res/layout/item_attachment_default.xml
+++ b/app/src/main/res/layout/item_attachment_default.xml
@@ -20,6 +20,7 @@
             android:layout_height="wrap_content"
             android:layout_gravity="center"
             android:layout_margin="@dimen/standard_half_margin"
+            android:transitionName="@string/transition_attachment_preview"
             app:srcCompat="@drawable/ic_attach_file_grey600_24dp" />
 
         <androidx.appcompat.widget.AppCompatImageView
diff --git a/app/src/main/res/layout/item_attachment_image.xml b/app/src/main/res/layout/item_attachment_image.xml
index 9b9d64416..42ab7bc66 100644
--- a/app/src/main/res/layout/item_attachment_image.xml
+++ b/app/src/main/res/layout/item_attachment_image.xml
@@ -11,6 +11,8 @@
         android:layout_width="match_parent"
         android:layout_height="match_parent"
         android:layout_gravity="center"
+        android:scaleType="centerCrop"
+        android:transitionName="@string/transition_attachment_preview"
         app:srcCompat="@drawable/ic_image_grey600_24dp" />
 
     <androidx.appcompat.widget.AppCompatImageView
diff --git a/app/src/main/res/values/setup.xml b/app/src/main/res/values/setup.xml
index e9b860fba..db81c60a1 100644
--- a/app/src/main/res/values/setup.xml
+++ b/app/src/main/res/values/setup.xml
@@ -33,4 +33,7 @@
     <integer name="minimum_server_app_major" translatable="false">0</integer>
     <integer name="minimum_server_app_minor" translatable="false">6</integer>
     <integer name="minimum_server_app_patch" translatable="false">4</integer>
+
+    <!-- Transitions -->
+    <string name="transition_attachment_preview" translatable="false">transition_attachment_preview</string>
 </resources>
\ No newline at end of file
diff --git a/app/src/main/res/values/styles.xml b/app/src/main/res/values/styles.xml
index 300a9e22a..1e3be799f 100644
--- a/app/src/main/res/values/styles.xml
+++ b/app/src/main/res/values/styles.xml
@@ -1,4 +1,4 @@
-<resources>
+<resources xmlns:tools="http://schemas.android.com/tools">
 
     <!-- Base application theme. -->
     <style name="AppTheme" parent="Theme.MaterialComponents.Light.DarkActionBar.Bridge">
@@ -6,7 +6,7 @@
         <item name="colorPrimaryDark">@color/primary</item>
         <item name="colorAccent">@color/primary</item>
         <item name="android:windowContentOverlay">@null</item>
-        <item name="android:elevation">@null</item>
+        <item name="android:elevation" tools:targetApi="lollipop">@null</item>
         <item name="windowActionBar">false</item>
         <item name="windowNoTitle">true</item>
     </style>
@@ -38,7 +38,7 @@
     <style name="PrimaryCTAButton" parent="android:Widget.DeviceDefault.Button">
         <item name="android:background">@color/primary</item>
         <item name="android:textColor">@color/fg_accent</item>
-        <item name="android:elevation">5dp</item>
+        <item name="android:elevation" tools:targetApi="lollipop">5dp</item>
     </style>
 
     <style name="NavigationView">
@@ -51,11 +51,15 @@
     </style>
 
     <style name="DeleteDialogDarkTheme" parent="DialogDarkTheme">
-        <item name="android:buttonBarPositiveButtonStyle">@style/PositiveButtonStyle</item>
+        <item name="android:buttonBarPositiveButtonStyle" tools:targetApi="lollipop">
+            @style/PositiveButtonStyle
+        </item>
     </style>
 
     <style name="DeleteDialogTheme" parent="ThemeOverlay.AppCompat.Dialog.Alert">
-        <item name="android:buttonBarPositiveButtonStyle">@style/PositiveButtonStyle</item>
+        <item name="android:buttonBarPositiveButtonStyle" tools:targetApi="lollipop">
+            @style/PositiveButtonStyle
+        </item>
     </style>
 
     <style name="PositiveButtonStyle" parent="Widget.AppCompat.Button.ButtonBar.AlertDialog">
@@ -63,6 +67,13 @@
     </style>
 
     <style name="Spinner" parent="ThemeOverlay.AppCompat.Dark">
-            <item name="android:textColor">@android:color/white</item>
+        <item name="android:textColor">@android:color/white</item>
+    </style>
+
+    <style name="TransparentTheme" parent="Theme.AppCompat.NoActionBar">
+        <item name="android:windowNoTitle">true</item>
+        <item name="android:windowBackground">@android:color/background_dark</item>
+        <item name="android:colorBackgroundCacheHint">@null</item>
+        <item name="android:windowIsTranslucent">true</item>
     </style>
 </resources>