Display attachments in a dialog to give the user a chance to cancel the upload

Signed-off-by: Stefan Niedermann <info@niedermann.it>

18 files changed, 265 insertions, 65 deletions

diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/assignee/CardAssigneeDialog.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/assignee/CardAssigneeDialog.java
index 74c89d830..34d2eb3f3 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/assignee/CardAssigneeDialog.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/assignee/CardAssigneeDialog.java
@@ -19,7 +19,7 @@ import com.bumptech.glide.Glide;
 import java.io.Serializable;
 
 import it.niedermann.nextcloud.deck.R;
-import it.niedermann.nextcloud.deck.databinding.DialogAssigneeBinding;
+import it.niedermann.nextcloud.deck.databinding.DialogPreviewBinding;
 import it.niedermann.nextcloud.deck.model.User;
 import it.niedermann.nextcloud.deck.ui.branding.BrandedDeleteAlertDialogBuilder;
 import it.niedermann.nextcloud.deck.ui.branding.BrandedDialogFragment;
@@ -27,10 +27,11 @@ import it.niedermann.nextcloud.deck.ui.card.EditCardViewModel;
 
 import static it.niedermann.nextcloud.deck.DeckApplication.isDarkTheme;
 
+@Deprecated
 public class CardAssigneeDialog extends BrandedDialogFragment {
 
     private static final String KEY_USER = "user";
-    private DialogAssigneeBinding binding;
+    private DialogPreviewBinding binding;
     private EditCardViewModel viewModel;
 
     @Nullable
@@ -63,7 +64,7 @@ public class CardAssigneeDialog extends BrandedDialogFragment {
     @NonNull
     @Override
     public Dialog onCreateDialog(Bundle savedInstanceState) {
-        binding = DialogAssigneeBinding.inflate(LayoutInflater.from(requireContext()));
+        binding = DialogPreviewBinding.inflate(LayoutInflater.from(requireContext()));
         viewModel = new ViewModelProvider(requireActivity()).get(EditCardViewModel.class);
 
         AlertDialog.Builder dialogBuilder = new BrandedDeleteAlertDialogBuilder(requireContext());
@@ -95,7 +96,7 @@ public class CardAssigneeDialog extends BrandedDialogFragment {
                 .placeholder(circularProgressDrawable)
                 .error(R.drawable.ic_person_grey600_24dp)
                 .into(binding.avatar));
-        binding.displayName.setText(user.getDisplayname());
+        binding.title.setText(user.getDisplayname());
     }
 
     @Override
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/CardAttachmentsFragment.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/CardAttachmentsFragment.java
index b137b1b7f..24b94ebde 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/CardAttachmentsFragment.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/CardAttachmentsFragment.java
@@ -55,6 +55,8 @@ import it.niedermann.nextcloud.deck.ui.card.attachments.picker.ContactAdapter;
 import it.niedermann.nextcloud.deck.ui.card.attachments.picker.FileAdapter;
 import it.niedermann.nextcloud.deck.ui.card.attachments.picker.FileAdapterLegacy;
 import it.niedermann.nextcloud.deck.ui.card.attachments.picker.GalleryAdapter;
+import it.niedermann.nextcloud.deck.ui.card.attachments.previewdialog.PreviewDialog;
+import it.niedermann.nextcloud.deck.ui.card.attachments.previewdialog.PreviewDialogViewModel;
 import it.niedermann.nextcloud.deck.ui.exception.ExceptionDialogFragment;
 import it.niedermann.nextcloud.deck.ui.takephoto.TakePhotoActivity;
 import it.niedermann.nextcloud.deck.util.VCardUtil;
@@ -84,7 +86,8 @@ import static java.net.HttpURLConnection.HTTP_CONFLICT;
 public class CardAttachmentsFragment extends BrandedFragment implements AttachmentDeletedListener, AttachmentClickedListener {
 
     private FragmentCardEditTabAttachmentsBinding binding;
-    private EditCardViewModel viewModel;
+    private EditCardViewModel editViewModel;
+    private PreviewDialogViewModel previewViewModel;
     private BottomSheetBehavior<LinearLayout> mBottomSheetBehaviour;
 
     private static final int REQUEST_CODE_PICK_FILE = 1;
@@ -115,7 +118,8 @@ public class CardAttachmentsFragment extends BrandedFragment implements Attachme
                              Bundle savedInstanceState) {
 
         binding = FragmentCardEditTabAttachmentsBinding.inflate(inflater, container, false);
-        viewModel = new ViewModelProvider(requireActivity()).get(EditCardViewModel.class);
+        editViewModel = new ViewModelProvider(requireActivity()).get(EditCardViewModel.class);
+        previewViewModel = new ViewModelProvider(requireActivity()).get(PreviewDialogViewModel.class);
         binding.bottomNavigation.setOnNavigationItemSelectedListener(item -> {
             if (item.getItemId() == R.id.gallery) {
                 showGalleryPicker();
@@ -129,7 +133,7 @@ public class CardAttachmentsFragment extends BrandedFragment implements Attachme
 
         // This might be a zombie fragment with an empty EditCardViewModel after Android killed the activity (but not the fragment instance
         // See https://github.com/stefan-niedermann/nextcloud-deck/issues/478
-        if (viewModel.getFullCard() == null) {
+        if (editViewModel.getFullCard() == null) {
             DeckLog.logError(new IllegalStateException("Cannot populate " + CardAttachmentsFragment.class.getSimpleName() + " because viewModel.getFullCard() is null"));
             return binding.getRoot();
         }
@@ -139,8 +143,8 @@ public class CardAttachmentsFragment extends BrandedFragment implements Attachme
                 getChildFragmentManager(),
                 requireActivity().getMenuInflater(),
                 this,
-                viewModel.getAccount(),
-                viewModel.getFullCard().getLocalId());
+                editViewModel.getAccount(),
+                editViewModel.getFullCard().getLocalId());
         binding.attachmentsList.setAdapter(adapter);
 
         adapter.isEmpty().observe(getViewLifecycleOwner(), (isEmpty) -> {
@@ -198,7 +202,7 @@ public class CardAttachmentsFragment extends BrandedFragment implements Attachme
             }
         });
         binding.attachmentsList.setLayoutManager(glm);
-        if (!viewModel.isCreateMode()) {
+        if (!editViewModel.isCreateMode()) {
             // https://android-developers.googleblog.com/2018/02/continuous-shared-element-transitions.html?m=1
             // https://github.com/android/animation-samples/blob/master/GridToPager/app/src/main/java/com/google/samples/gridtopager/fragment/ImagePagerFragment.java
             setExitSharedElementCallback(new SharedElementCallback() {
@@ -211,10 +215,10 @@ public class CardAttachmentsFragment extends BrandedFragment implements Attachme
                     }
                 }
             });
-            adapter.setAttachments(viewModel.getFullCard().getAttachments(), viewModel.getFullCard().getId());
+            adapter.setAttachments(editViewModel.getFullCard().getAttachments(), editViewModel.getFullCard().getId());
         }
 
-        if (viewModel.canEdit()) {
+        if (editViewModel.canEdit()) {
             binding.fab.setOnClickListener(v -> {
                 if (SDK_INT < LOLLIPOP) {
                     openNativeFilePicker();
@@ -293,7 +297,15 @@ public class CardAttachmentsFragment extends BrandedFragment implements Attachme
                 requestPermissions(new String[]{READ_EXTERNAL_STORAGE, CAMERA}, REQUEST_CODE_PICK_GALLERY_PERMISSION);
             } else {
                 unbindPickerAdapter();
-                pickerAdapter = new GalleryAdapter(requireContext(), uri -> onActivityResult(REQUEST_CODE_PICK_FILE, RESULT_OK, new Intent().setData(uri)), this::openNativeCameraPicker, getViewLifecycleOwner());
+                pickerAdapter = new GalleryAdapter(requireContext(), (uri, pair) -> {
+                    previewViewModel.prepareDialog(pair.first, pair.second);
+                    PreviewDialog.newInstance().show(getChildFragmentManager(), PreviewDialog.class.getSimpleName());
+                    observeOnce(previewViewModel.getResult(), getViewLifecycleOwner(), (submitPositive) -> {
+                        if (submitPositive) {
+                            onActivityResult(REQUEST_CODE_PICK_FILE, RESULT_OK, new Intent().setData(uri));
+                        }
+                    });
+                }, this::openNativeCameraPicker, getViewLifecycleOwner());
                 binding.pickerRecyclerView.setLayoutManager(new GridLayoutManager(requireContext(), 3));
                 binding.pickerRecyclerView.setAdapter(pickerAdapter);
             }
@@ -306,7 +318,15 @@ public class CardAttachmentsFragment extends BrandedFragment implements Attachme
                 requestPermissions(new String[]{READ_CONTACTS}, REQUEST_CODE_PICK_CONTACT_PICKER_PERMISSION);
             } else {
                 unbindPickerAdapter();
-                pickerAdapter = new ContactAdapter(requireContext(), uri -> onActivityResult(REQUEST_CODE_PICK_CONTACT, RESULT_OK, new Intent().setData(uri)), this::openNativeContactPicker);
+                pickerAdapter = new ContactAdapter(requireContext(), (uri, pair) -> {
+                    previewViewModel.prepareDialog(pair.first, pair.second);
+                    PreviewDialog.newInstance().show(getChildFragmentManager(), PreviewDialog.class.getSimpleName());
+                    observeOnce(previewViewModel.getResult(), getViewLifecycleOwner(), (submitPositive) -> {
+                        if (submitPositive) {
+                            onActivityResult(REQUEST_CODE_PICK_CONTACT, RESULT_OK, new Intent().setData(uri));
+                        }
+                    });
+                }, this::openNativeContactPicker);
                 binding.pickerRecyclerView.setLayoutManager(new LinearLayoutManager(requireContext()));
                 binding.pickerRecyclerView.setAdapter(pickerAdapter);
             }
@@ -324,7 +344,15 @@ public class CardAttachmentsFragment extends BrandedFragment implements Attachme
 //                        // TODO Only usable with Scoped Storage
 //                        pickerAdapter = new FileAdapter(requireContext(), uri -> onActivityResult(REQUEST_CODE_PICK_FILE, RESULT_OK, new Intent().setData(uri)), this::openNativeFilePicker);
 //                    } else {
-                    pickerAdapter = new FileAdapterLegacy(requireContext(), uri -> onActivityResult(REQUEST_CODE_PICK_FILE, RESULT_OK, new Intent().setData(uri)), this::openNativeFilePicker);
+                    pickerAdapter = new FileAdapterLegacy(requireContext(), (uri, pair) -> {
+                        previewViewModel.prepareDialog(pair.first, pair.second);
+                        PreviewDialog.newInstance().show(getChildFragmentManager(), PreviewDialog.class.getSimpleName());
+                        observeOnce(previewViewModel.getResult(), getViewLifecycleOwner(), (submitPositive) -> {
+                            if (submitPositive) {
+                                onActivityResult(REQUEST_CODE_PICK_FILE, RESULT_OK, new Intent().setData(uri));
+                            }
+                        });
+                    }, this::openNativeFilePicker);
 //                    }
                     binding.pickerRecyclerView.setLayoutManager(new LinearLayoutManager(requireContext()));
                     binding.pickerRecyclerView.setAdapter(pickerAdapter);
@@ -337,7 +365,7 @@ public class CardAttachmentsFragment extends BrandedFragment implements Attachme
         if (SDK_INT >= LOLLIPOP) {
             startActivityForResult(TakePhotoActivity.createIntent(requireContext()), REQUEST_CODE_PICK_CAMERA);
         } else {
-            ExceptionDialogFragment.newInstance(new UnsupportedOperationException("This feature requires Android 5"), viewModel.getAccount()).show(getChildFragmentManager(), ExceptionDialogFragment.class.getSimpleName());
+            ExceptionDialogFragment.newInstance(new UnsupportedOperationException("This feature requires Android 5"), editViewModel.getAccount()).show(getChildFragmentManager(), ExceptionDialogFragment.class.getSimpleName());
         }
     }
 
@@ -388,7 +416,7 @@ public class CardAttachmentsFragment extends BrandedFragment implements Attachme
                                 : requireContext().getContentResolver().getType(sourceUri));
                         mBottomSheetBehaviour.setState(STATE_HIDDEN);
                     } catch (Exception e) {
-                        ExceptionDialogFragment.newInstance(e, viewModel.getAccount()).show(getChildFragmentManager(), ExceptionDialogFragment.class.getSimpleName());
+                        ExceptionDialogFragment.newInstance(e, editViewModel.getAccount()).show(getChildFragmentManager(), ExceptionDialogFragment.class.getSimpleName());
                     }
                 }
                 break;
@@ -416,15 +444,14 @@ public class CardAttachmentsFragment extends BrandedFragment implements Attachme
             case ContentResolver.SCHEME_CONTENT:
             case ContentResolver.SCHEME_FILE: {
                 DeckLog.verbose("--- found content URL " + sourceUri.getPath());
-                final File fileToUpload = copyContentUriToTempFile(requireContext(), sourceUri, viewModel.getAccount().getId(), viewModel.getFullCard().getLocalId());
-                for (Attachment existingAttachment : viewModel.getFullCard().getAttachments()) {
+                final File fileToUpload = copyContentUriToTempFile(requireContext(), sourceUri, editViewModel.getAccount().getId(), editViewModel.getFullCard().getLocalId());
+                for (Attachment existingAttachment : editViewModel.getFullCard().getAttachments()) {
                     final String existingPath = existingAttachment.getLocalPath();
                     if (existingPath != null && existingPath.equals(fileToUpload.getAbsolutePath())) {
                         BrandedSnackbar.make(binding.coordinatorLayout, R.string.attachment_already_exists, Snackbar.LENGTH_LONG).show();
                         return;
                     }
                 }
-
                 final Instant now = Instant.now();
                 final Attachment a = new Attachment();
                 a.setMimetype(mimeType);
@@ -436,24 +463,24 @@ public class CardAttachmentsFragment extends BrandedFragment implements Attachme
                 a.setLastModifiedLocal(now);
                 a.setCreatedAt(now);
                 a.setStatusEnum(DBStatus.LOCAL_EDITED);
-                viewModel.getFullCard().getAttachments().add(0, a);
+                editViewModel.getFullCard().getAttachments().add(0, a);
                 adapter.addAttachment(a);
-                if (!viewModel.isCreateMode()) {
-                    WrappedLiveData<Attachment> liveData = syncManager.addAttachmentToCard(viewModel.getAccount().getId(), viewModel.getFullCard().getLocalId(), a.getMimetype(), fileToUpload);
+                if (!editViewModel.isCreateMode()) {
+                    WrappedLiveData<Attachment> liveData = syncManager.addAttachmentToCard(editViewModel.getAccount().getId(), editViewModel.getFullCard().getLocalId(), a.getMimetype(), fileToUpload);
                     observeOnce(liveData, getViewLifecycleOwner(), (next) -> {
                         if (liveData.hasError()) {
                             Throwable t = liveData.getError();
                             if (t instanceof NextcloudHttpRequestFailedException && ((NextcloudHttpRequestFailedException) t).getStatusCode() == HTTP_CONFLICT) {
                                 // https://github.com/stefan-niedermann/nextcloud-deck/issues/534
-                                viewModel.getFullCard().getAttachments().remove(a);
+                                editViewModel.getFullCard().getAttachments().remove(a);
                                 adapter.removeAttachment(a);
                                 BrandedSnackbar.make(binding.coordinatorLayout, R.string.attachment_already_exists, Snackbar.LENGTH_LONG).show();
                             } else {
-                                ExceptionDialogFragment.newInstance(new UploadAttachmentFailedException("Unknown URI scheme", t), viewModel.getAccount()).show(getChildFragmentManager(), ExceptionDialogFragment.class.getSimpleName());
+                                ExceptionDialogFragment.newInstance(new UploadAttachmentFailedException("Unknown URI scheme", t), editViewModel.getAccount()).show(getChildFragmentManager(), ExceptionDialogFragment.class.getSimpleName());
                             }
                         } else {
-                            viewModel.getFullCard().getAttachments().remove(a);
-                            viewModel.getFullCard().getAttachments().add(0, next);
+                            editViewModel.getFullCard().getAttachments().remove(a);
+                            editViewModel.getFullCard().getAttachments().add(0, next);
                             adapter.replaceAttachment(a, next);
                         }
                     });
@@ -503,12 +530,12 @@ public class CardAttachmentsFragment extends BrandedFragment implements Attachme
     @Override
     public void onAttachmentDeleted(Attachment attachment) {
         adapter.removeAttachment(attachment);
-        viewModel.getFullCard().getAttachments().remove(attachment);
-        if (!viewModel.isCreateMode() && attachment.getLocalId() != null) {
-            final WrappedLiveData<Void> deleteLiveData = syncManager.deleteAttachmentOfCard(viewModel.getAccount().getId(), viewModel.getFullCard().getLocalId(), attachment.getLocalId());
+        editViewModel.getFullCard().getAttachments().remove(attachment);
+        if (!editViewModel.isCreateMode() && attachment.getLocalId() != null) {
+            final WrappedLiveData<Void> deleteLiveData = syncManager.deleteAttachmentOfCard(editViewModel.getAccount().getId(), editViewModel.getFullCard().getLocalId(), attachment.getLocalId());
             observeOnce(deleteLiveData, this, (next) -> {
                 if (deleteLiveData.hasError() && !SyncManager.ignoreExceptionOnVoidError(deleteLiveData.getError())) {
-                    ExceptionDialogFragment.newInstance(deleteLiveData.getError(), viewModel.getAccount()).show(getChildFragmentManager(), ExceptionDialogFragment.class.getSimpleName());
+                    ExceptionDialogFragment.newInstance(deleteLiveData.getError(), editViewModel.getAccount()).show(getChildFragmentManager(), ExceptionDialogFragment.class.getSimpleName());
                 }
             });
         }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/AbstractCursorPickerAdapter.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/AbstractCursorPickerAdapter.java
index 73058c757..743e3382e 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/AbstractCursorPickerAdapter.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/AbstractCursorPickerAdapter.java
@@ -5,13 +5,16 @@ import android.content.Context;
 import android.database.Cursor;
 import android.graphics.Bitmap;
 import android.net.Uri;
+import android.util.Pair;
 
 import androidx.annotation.NonNull;
 import androidx.recyclerview.widget.RecyclerView;
 
+import com.bumptech.glide.RequestBuilder;
+
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
-import java.util.function.Consumer;
+import java.util.function.BiConsumer;
 
 import static android.database.Cursor.FIELD_TYPE_INTEGER;
 import static android.database.Cursor.FIELD_TYPE_NULL;
@@ -29,7 +32,7 @@ public abstract class AbstractCursorPickerAdapter<T extends RecyclerView.ViewHol
     protected final int columnIndex;
     private final int columnIndexType;
     @NonNull
-    protected final Consumer<Uri> onSelect;
+    protected final BiConsumer<Uri, Pair<String, RequestBuilder<?>>> onSelect;
     @NonNull
     protected final Runnable openNativePicker;
     @NonNull
@@ -44,15 +47,15 @@ public abstract class AbstractCursorPickerAdapter<T extends RecyclerView.ViewHol
     @NonNull
     protected final ExecutorService bindExecutor = Executors.newFixedThreadPool(1);
 
-    public AbstractCursorPickerAdapter(@NonNull Context context, @NonNull Consumer<Uri> onSelect, @NonNull Runnable openNativePicker, Uri subject, String idColumn, String sortOrder) {
+    public AbstractCursorPickerAdapter(@NonNull Context context, @NonNull BiConsumer<Uri, Pair<String, RequestBuilder<?>>> onSelect, @NonNull Runnable openNativePicker, Uri subject, String idColumn, String sortOrder) {
         this(context, onSelect, openNativePicker, subject, idColumn, new String[]{idColumn}, sortOrder);
     }
 
-    public AbstractCursorPickerAdapter(@NonNull Context context, @NonNull Consumer<Uri> onSelect, @NonNull Runnable openNativePicker, Uri subject, String idColumn, String[] requestedColumns, String sortOrder) {
+    public AbstractCursorPickerAdapter(@NonNull Context context, @NonNull BiConsumer<Uri, Pair<String, RequestBuilder<?>>> onSelect, @NonNull Runnable openNativePicker, Uri subject, String idColumn, String[] requestedColumns, String sortOrder) {
         this(context, onSelect, openNativePicker, idColumn, requireNonNull(context.getContentResolver().query(subject, requestedColumns, null, null, sortOrder)));
     }
 
-    public AbstractCursorPickerAdapter(@NonNull Context context, @NonNull Consumer<Uri> onSelect, @NonNull Runnable openNativePicker, String idColumn, @NonNull Cursor cursor) {
+    public AbstractCursorPickerAdapter(@NonNull Context context, @NonNull BiConsumer<Uri, Pair<String, RequestBuilder<?>>> onSelect, @NonNull Runnable openNativePicker, String idColumn, @NonNull Cursor cursor) {
         this.contentResolver = context.getContentResolver();
         this.onSelect = onSelect;
         this.openNativePicker = openNativePicker;
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/AbstractPickerAdapter.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/AbstractPickerAdapter.java
index d04065aa4..a17794841 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/AbstractPickerAdapter.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/AbstractPickerAdapter.java
@@ -18,4 +18,4 @@ public abstract class AbstractPickerAdapter<T extends RecyclerView.ViewHolder> e
      * Call this method when the {@link AbstractPickerAdapter} is no longer need to free resources.
      */
     public abstract void onDestroy();
-}
+}
\ No newline at end of file
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/ContactAdapter.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/ContactAdapter.java
index 874127103..e334cc492 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/ContactAdapter.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/ContactAdapter.java
@@ -9,15 +9,18 @@ import android.os.Handler;
 import android.os.Looper;
 import android.provider.ContactsContract;
 import android.text.TextUtils;
+import android.util.Pair;
 import android.view.LayoutInflater;
 import android.view.ViewGroup;
 
 import androidx.annotation.NonNull;
 import androidx.recyclerview.widget.RecyclerView;
 
+import com.bumptech.glide.RequestBuilder;
+
 import java.io.IOException;
 import java.io.InputStream;
-import java.util.function.Consumer;
+import java.util.function.BiConsumer;
 
 import it.niedermann.nextcloud.deck.databinding.ItemPickerNativeBinding;
 import it.niedermann.nextcloud.deck.databinding.ItemPickerUserBinding;
@@ -37,7 +40,7 @@ public class ContactAdapter extends AbstractCursorPickerAdapter<RecyclerView.Vie
     private final int lookupKeyColumnIndex;
     private final int displayNameColumnIndex;
 
-    public ContactAdapter(@NonNull Context context, @NonNull Consumer<Uri> onSelect, @NonNull Runnable onSelectPicker) {
+    public ContactAdapter(@NonNull Context context, @NonNull BiConsumer<Uri, Pair<String, RequestBuilder<?>>> onSelect, @NonNull Runnable onSelectPicker) {
         super(context, onSelect, onSelectPicker, CONTENT_URI, _ID, new String[]{_ID, LOOKUP_KEY, DISPLAY_NAME}, SORT_KEY_PRIMARY);
         lookupKeyColumnIndex = cursor.getColumnIndex(LOOKUP_KEY);
         displayNameColumnIndex = cursor.getColumnIndex(DISPLAY_NAME);
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/ContactItemViewHolder.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/ContactItemViewHolder.java
index b8d52a1d3..f403fed21 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/ContactItemViewHolder.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/ContactItemViewHolder.java
@@ -4,15 +4,17 @@ import android.graphics.Bitmap;
 import android.graphics.drawable.ColorDrawable;
 import android.net.Uri;
 import android.text.TextUtils;
+import android.util.Pair;
 
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.recyclerview.widget.RecyclerView;
 
 import com.bumptech.glide.Glide;
+import com.bumptech.glide.RequestBuilder;
 import com.bumptech.glide.request.RequestOptions;
 
-import java.util.function.Consumer;
+import java.util.function.BiConsumer;
 
 import it.niedermann.nextcloud.deck.R;
 import it.niedermann.nextcloud.deck.databinding.ItemPickerUserBinding;
@@ -30,9 +32,9 @@ public class ContactItemViewHolder extends RecyclerView.ViewHolder {
         this.binding = binding;
     }
 
-    public void bind(@NonNull Uri uri, @Nullable Bitmap image, @NonNull String displayName, @Nullable String contactInformation, @NonNull Consumer<Uri> onSelect) {
-        itemView.setOnClickListener((v) -> onSelect.accept(uri));
-        binding.displayName.setText(displayName);
+    public void bind(@NonNull Uri uri, @Nullable Bitmap image, @NonNull String displayName, @Nullable String contactInformation, @NonNull BiConsumer<Uri, Pair<String, RequestBuilder<?>>> onSelect) {
+        itemView.setOnClickListener((v) -> onSelect.accept(uri, new Pair<>(displayName, image == null ? null : Glide.with(itemView.getContext()).load(image))));
+        binding.title.setText(displayName);
         binding.contactInformation.setText(contactInformation);
         if (image == null) {
             binding.initials.setVisibility(VISIBLE);
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/FileAdapter.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/FileAdapter.java
index 47dd3f7a3..46633df6c 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/FileAdapter.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/FileAdapter.java
@@ -6,6 +6,7 @@ import android.net.Uri;
 import android.os.Handler;
 import android.os.Looper;
 import android.provider.MediaStore;
+import android.util.Pair;
 import android.view.LayoutInflater;
 import android.view.ViewGroup;
 
@@ -13,7 +14,9 @@ import androidx.annotation.NonNull;
 import androidx.annotation.RequiresApi;
 import androidx.recyclerview.widget.RecyclerView;
 
-import java.util.function.Consumer;
+import com.bumptech.glide.RequestBuilder;
+
+import java.util.function.BiConsumer;
 
 import it.niedermann.nextcloud.deck.databinding.ItemAttachmentDefaultBinding;
 import it.niedermann.nextcloud.deck.databinding.ItemPickerNativeBinding;
@@ -35,7 +38,7 @@ public class FileAdapter extends AbstractCursorPickerAdapter<RecyclerView.ViewHo
     private final int modifiedColumnIndex;
     private final int mimeTypeColumnIndex;
 
-    private FileAdapter(@NonNull Context context, @NonNull Consumer<Uri> onSelect, @NonNull Runnable onSelectPicker) {
+    private FileAdapter(@NonNull Context context, @NonNull BiConsumer<Uri, Pair<String, RequestBuilder<?>>> onSelect, @NonNull Runnable onSelectPicker) {
         super(context, onSelect, onSelectPicker, _ID, requireNonNull(context.getContentResolver().query(EXTERNAL_CONTENT_URI, new String[]{_ID, TITLE, SIZE, DATE_MODIFIED, MIME_TYPE}, null, null, DATE_ADDED + " DESC")));
         displayNameColumnIndex = cursor.getColumnIndex(TITLE);
         sizeColumnIndex = cursor.getColumnIndex(SIZE);
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/FileAdapterLegacy.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/FileAdapterLegacy.java
index a338e9d75..5688ab15b 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/FileAdapterLegacy.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/FileAdapterLegacy.java
@@ -3,16 +3,19 @@ package it.niedermann.nextcloud.deck.ui.card.attachments.picker;
 import android.content.Context;
 import android.net.Uri;
 import android.os.Environment;
+import android.util.Pair;
 import android.view.LayoutInflater;
 import android.view.ViewGroup;
 
 import androidx.annotation.NonNull;
 import androidx.recyclerview.widget.RecyclerView;
 
+import com.bumptech.glide.RequestBuilder;
+
 import java.io.File;
 import java.util.Arrays;
 import java.util.List;
-import java.util.function.Consumer;
+import java.util.function.BiConsumer;
 
 import it.niedermann.nextcloud.deck.databinding.ItemAttachmentDefaultBinding;
 import it.niedermann.nextcloud.deck.databinding.ItemPickerNativeBinding;
@@ -31,11 +34,11 @@ public class FileAdapterLegacy extends AbstractPickerAdapter<RecyclerView.ViewHo
     @NonNull
     private final List<File> files;
     @NonNull
-    protected final Consumer<Uri> onSelect;
+    protected final BiConsumer<Uri, Pair<String, RequestBuilder<?>>> onSelect;
     @NonNull
     protected final Runnable openNativePicker;
 
-    public FileAdapterLegacy(@NonNull Context context, @NonNull Consumer<Uri> onSelect, @NonNull Runnable openNativePicker) {
+    public FileAdapterLegacy(@NonNull Context context, @NonNull BiConsumer<Uri, Pair<String, RequestBuilder<?>>> onSelect, @NonNull Runnable openNativePicker) {
         // TODO run in separate thread?
         this.context = context;
         this.onSelect = onSelect;
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/FileItemViewHolder.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/FileItemViewHolder.java
index 50733dfbe..f7d64aca8 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/FileItemViewHolder.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/FileItemViewHolder.java
@@ -1,12 +1,15 @@
 package it.niedermann.nextcloud.deck.ui.card.attachments.picker;
 
 import android.net.Uri;
+import android.util.Pair;
 
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.recyclerview.widget.RecyclerView;
 
-import java.util.function.Consumer;
+import com.bumptech.glide.RequestBuilder;
+
+import java.util.function.BiConsumer;
 
 import it.niedermann.nextcloud.deck.R;
 import it.niedermann.nextcloud.deck.databinding.ItemAttachmentDefaultBinding;
@@ -24,8 +27,8 @@ public class FileItemViewHolder extends RecyclerView.ViewHolder {
         this.binding = binding;
     }
 
-    public void bind(@NonNull Uri uri, @NonNull String name, String mimeType, long size, long modified, @Nullable Consumer<Uri> onSelect) {
-        itemView.setOnClickListener(onSelect == null ? null : (v) -> onSelect.accept(uri));
+    public void bind(@NonNull Uri uri, @NonNull String name, String mimeType, long size, long modified, @Nullable BiConsumer<Uri, Pair<String, RequestBuilder<?>>> onSelect) {
+        itemView.setOnClickListener(onSelect == null ? null : (v) -> onSelect.accept(uri, new Pair<>(name, null)));
         binding.filename.setText(name);
         binding.filesize.setText(formatFileSize(binding.filesize.getContext(), size));
         binding.modified.setText(getRelativeDateTimeString(binding.modified.getContext(), modified));
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/GalleryAdapter.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/GalleryAdapter.java
index 0be85d9e5..7f5c254c3 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/GalleryAdapter.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/GalleryAdapter.java
@@ -8,6 +8,7 @@ import android.net.Uri;
 import android.os.Handler;
 import android.os.Looper;
 import android.provider.MediaStore;
+import android.util.Pair;
 import android.util.Size;
 import android.view.LayoutInflater;
 import android.view.ViewGroup;
@@ -16,8 +17,10 @@ import androidx.annotation.NonNull;
 import androidx.lifecycle.LifecycleOwner;
 import androidx.recyclerview.widget.RecyclerView;
 
+import com.bumptech.glide.RequestBuilder;
+
 import java.io.IOException;
-import java.util.function.Consumer;
+import java.util.function.BiConsumer;
 
 import it.niedermann.nextcloud.deck.databinding.ItemAttachmentImageBinding;
 import it.niedermann.nextcloud.deck.databinding.ItemPhotoPreviewBinding;
@@ -37,7 +40,7 @@ public class GalleryAdapter extends AbstractCursorPickerAdapter<RecyclerView.Vie
             ? MediaStore.Images.Media.DATE_TAKEN
             : MediaStore.Images.Media.DATE_ADDED;
 
-    public GalleryAdapter(@NonNull Context context, @NonNull Consumer<Uri> onSelect, @NonNull Runnable openNativePicker, @NonNull LifecycleOwner lifecycleOwner) {
+    public GalleryAdapter(@NonNull Context context, @NonNull BiConsumer<Uri, Pair<String, RequestBuilder<?>>> onSelect, @NonNull Runnable openNativePicker, @NonNull LifecycleOwner lifecycleOwner) {
         super(context, onSelect, openNativePicker, EXTERNAL_CONTENT_URI, _ID, sortOrder + " DESC");
         this.lifecycleOwner = lifecycleOwner;
         notifyItemRangeInserted(0, getItemCount());
@@ -90,7 +93,7 @@ public class GalleryAdapter extends AbstractCursorPickerAdapter<RecyclerView.Vie
     @Override
     public void onViewDetachedFromWindow(@NonNull RecyclerView.ViewHolder holder) {
         super.onViewDetachedFromWindow(holder);
-        if(holder instanceof GalleryPhotoPreviewItemViewHolder) {
+        if (holder instanceof GalleryPhotoPreviewItemViewHolder) {
             ((GalleryPhotoPreviewItemViewHolder) holder).unbind();
         }
     }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/GalleryItemViewHolder.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/GalleryItemViewHolder.java
index d83876f0e..346fca9c3 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/GalleryItemViewHolder.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/GalleryItemViewHolder.java
@@ -2,23 +2,22 @@ package it.niedermann.nextcloud.deck.ui.card.attachments.picker;
 
 import android.graphics.Bitmap;
 import android.net.Uri;
+import android.util.Pair;
 
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.recyclerview.widget.RecyclerView;
 
 import com.bumptech.glide.Glide;
+import com.bumptech.glide.RequestBuilder;
 
-import java.util.concurrent.ExecutorService;
-import java.util.concurrent.Executors;
-import java.util.function.Consumer;
+import java.util.function.BiConsumer;
 
 import it.niedermann.nextcloud.deck.R;
 import it.niedermann.nextcloud.deck.databinding.ItemAttachmentImageBinding;
 
 public class GalleryItemViewHolder extends RecyclerView.ViewHolder {
 
-    private final ExecutorService executor = Executors.newCachedThreadPool();
     private final ItemAttachmentImageBinding binding;
 
     public GalleryItemViewHolder(@NonNull ItemAttachmentImageBinding binding) {
@@ -26,8 +25,8 @@ public class GalleryItemViewHolder extends RecyclerView.ViewHolder {
         this.binding = binding;
     }
 
-    public void bind(@NonNull Uri uri, @Nullable Bitmap image, @NonNull Consumer<Uri> onSelect) {
-        itemView.setOnClickListener((v) -> onSelect.accept(uri));
+    public void bind(@NonNull Uri uri, @Nullable Bitmap image, @NonNull BiConsumer<Uri, Pair<String, RequestBuilder<?>>> onSelect) {
+        itemView.setOnClickListener((v) -> onSelect.accept(uri, new Pair<>(null, Glide.with(itemView.getContext()).load(image))));
         Glide.with(itemView.getContext())
                 .load(image)
                 .placeholder(R.drawable.ic_image_grey600_24dp)
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/previewdialog/PreviewDialog.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/previewdialog/PreviewDialog.java
new file mode 100644
index 000000000..8ebdf1b50
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/previewdialog/PreviewDialog.java
@@ -0,0 +1,102 @@
+package it.niedermann.nextcloud.deck.ui.card.attachments.previewdialog;
+
+import android.app.Dialog;
+import android.content.Context;
+import android.content.DialogInterface;
+import android.graphics.Color;
+import android.os.Bundle;
+import android.text.TextUtils;
+import android.view.LayoutInflater;
+
+import androidx.annotation.NonNull;
+import androidx.fragment.app.DialogFragment;
+import androidx.lifecycle.LiveData;
+import androidx.lifecycle.ViewModelProvider;
+import androidx.swiperefreshlayout.widget.CircularProgressDrawable;
+
+import com.bumptech.glide.RequestBuilder;
+
+import it.niedermann.nextcloud.deck.R;
+import it.niedermann.nextcloud.deck.databinding.DialogPreviewBinding;
+import it.niedermann.nextcloud.deck.ui.branding.BrandedAlertDialogBuilder;
+import it.niedermann.nextcloud.deck.ui.branding.BrandedDialogFragment;
+
+import static android.view.View.GONE;
+import static android.view.View.VISIBLE;
+import static it.niedermann.nextcloud.deck.DeckApplication.isDarkTheme;
+
+public class PreviewDialog extends BrandedDialogFragment {
+
+    private DialogPreviewBinding binding;
+    private PreviewDialogViewModel viewModel;
+    private LiveData<RequestBuilder<?>> imageBuilder$;
+    private LiveData<String> title$;
+
+    @NonNull
+    @Override
+    public Dialog onCreateDialog(Bundle savedInstanceState) {
+        viewModel = new ViewModelProvider(requireActivity()).get(PreviewDialogViewModel.class);
+        binding = DialogPreviewBinding.inflate(LayoutInflater.from(requireContext()));
+
+        final Context context = requireContext();
+
+        this.imageBuilder$ = this.viewModel.getImageBuilder();
+        this.imageBuilder$.observe(requireActivity(), builder -> {
+            if (builder == null) {
+                binding.avatar.setVisibility(GONE);
+            } else {
+                final CircularProgressDrawable circularProgressDrawable = new CircularProgressDrawable(context);
+                circularProgressDrawable.setStrokeWidth(5f);
+                circularProgressDrawable.setCenterRadius(30f);
+                circularProgressDrawable.setColorSchemeColors(isDarkTheme(context) ? Color.LTGRAY : Color.DKGRAY);
+                circularProgressDrawable.start();
+                binding.avatar.setVisibility(VISIBLE);
+                binding.avatar.post(() -> builder
+                        .placeholder(circularProgressDrawable)
+                        .into(binding.avatar));
+            }
+        });
+        this.title$ = this.viewModel.getTitle();
+        this.title$.observe(requireActivity(), title -> {
+            if (TextUtils.isEmpty(title)) {
+                binding.title.setVisibility(GONE);
+            } else {
+                binding.title.setVisibility(VISIBLE);
+                binding.title.setText(title);
+            }
+        });
+
+        return new BrandedAlertDialogBuilder(requireContext())
+                .setPositiveButton(R.string.simple_attach, (d, w) -> {
+                    viewModel.setResult(true);
+                    dismiss();
+                })
+                .setNeutralButton(R.string.simple_close, (d, w) -> {
+                    viewModel.setResult(false);
+                    dismiss();
+                })
+                .setView(binding.getRoot())
+                .create();
+    }
+
+    @Override
+    public void onCancel(@NonNull DialogInterface dialog) {
+        viewModel.setResult(false);
+        super.onCancel(dialog);
+    }
+
+    @Override
+    public void applyBrand(int mainColor) {
+    }
+
+    @Override
+    public void onDestroy() {
+        this.imageBuilder$.removeObservers(requireActivity());
+        this.title$.removeObservers(requireActivity());
+        super.onDestroy();
+    }
+
+    public static DialogFragment newInstance() {
+        return new PreviewDialog();
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/previewdialog/PreviewDialogViewModel.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/previewdialog/PreviewDialogViewModel.java
new file mode 100644
index 000000000..8ee8a0e08
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/previewdialog/PreviewDialogViewModel.java
@@ -0,0 +1,50 @@
+package it.niedermann.nextcloud.deck.ui.card.attachments.previewdialog;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.lifecycle.LiveData;
+import androidx.lifecycle.MutableLiveData;
+import androidx.lifecycle.ViewModel;
+
+import com.bumptech.glide.RequestBuilder;
+
+import static androidx.lifecycle.Transformations.distinctUntilChanged;
+
+public class PreviewDialogViewModel extends ViewModel {
+
+    @NonNull
+    private final MutableLiveData<String> title$ = new MutableLiveData<>();
+    @NonNull
+    private final MutableLiveData<RequestBuilder<?>> imageBuilder$ = new MutableLiveData<>();
+    private MutableLiveData<Boolean> result$ = new MutableLiveData<>();
+
+    /**
+     * Call this before observing {@link #getResult()} to prepare the {@link PreviewDialog}.
+     */
+    public void prepareDialog(@Nullable String title, @Nullable RequestBuilder<?> imageBuilder) {
+        this.result$ = new MutableLiveData<>();
+        this.title$.setValue(title);
+        this.imageBuilder$.setValue(imageBuilder);
+    }
+
+    /**
+     * This will be a new instance after each call of {@link #prepareDialog(String, RequestBuilder)}.
+     *
+     * @return {@link Boolean#TRUE} if a positive action has been submitted, {@link Boolean#FALSE} if the dialog has been canceled.
+     */
+    public LiveData<Boolean> getResult() {
+        return this.result$;
+    }
+
+    protected LiveData<String> getTitle() {
+        return distinctUntilChanged(this.title$);
+    }
+
+    protected LiveData<RequestBuilder<?>> getImageBuilder() {
+        return distinctUntilChanged(this.imageBuilder$);
+    }
+
+    protected void setResult(boolean submittedPositive) {
+        result$.setValue(submittedPositive);
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/filter/FilterUserAdapter.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/filter/FilterUserAdapter.java
index 82230060c..4b75b985f 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/filter/FilterUserAdapter.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/filter/FilterUserAdapter.java
@@ -84,14 +84,14 @@ public class FilterUserAdapter extends RecyclerView.Adapter<FilterUserAdapter.Us
         }
 
         void bind(@NonNull final User user) {
-            binding.displayName.setText(user.getDisplayname());
+            binding.title.setText(user.getDisplayname());
             ViewUtil.addAvatar(binding.avatar, account.getUrl(), user.getUid(), avatarSize, R.drawable.ic_person_grey600_24dp);
             itemView.setSelected(selectedUsers.contains(user));
             bindClickListener(user);
         }
 
         public void bindNotAssigned() {
-            binding.displayName.setText(itemView.getContext().getString(R.string.simple_unassigned));
+            binding.title.setText(itemView.getContext().getString(R.string.simple_unassigned));
             Glide.with(itemView.getContext())
                     .load(R.drawable.ic_baseline_block_24)
                     .into(binding.avatar);
diff --git a/app/src/main/res/layout/dialog_assignee.xml b/app/src/main/res/layout/dialog_preview.xml
index 6f7157286..5ab35d63e 100644
--- a/app/src/main/res/layout/dialog_assignee.xml
+++ b/app/src/main/res/layout/dialog_preview.xml
@@ -15,7 +15,7 @@
 
     <TextView
         android:padding="?dialogPreferredPadding"
-        android:id="@+id/displayName"
+        android:id="@+id/title"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
         android:textAppearance="?attr/textAppearanceHeadline1"
diff --git a/app/src/main/res/layout/item_filter_user.xml b/app/src/main/res/layout/item_filter_user.xml
index 2c29bf5ad..0aced6dc2 100644
--- a/app/src/main/res/layout/item_filter_user.xml
+++ b/app/src/main/res/layout/item_filter_user.xml
@@ -31,7 +31,7 @@
     </FrameLayout>
 
     <TextView
-        android:id="@+id/displayName"
+        android:id="@+id/title"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
         android:layout_gravity="center"
diff --git a/app/src/main/res/layout/item_picker_user.xml b/app/src/main/res/layout/item_picker_user.xml
index 4418bf461..f9a17508e 100644
--- a/app/src/main/res/layout/item_picker_user.xml
+++ b/app/src/main/res/layout/item_picker_user.xml
@@ -41,7 +41,7 @@
         android:orientation="vertical">
 
         <TextView
-            android:id="@+id/displayName"
+            android:id="@+id/title"
             android:layout_width="match_parent"
             android:layout_height="wrap_content"
             android:layout_gravity="center"
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index 4d27bbae4..d6d9470fe 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -326,4 +326,5 @@
     <string name="downloads">Downloads</string>
     <string name="files">Files</string>
     <string name="gallery">Gallery</string>
+    <string name="simple_attach">attach</string>
 </resources>