feat(mobile): drag to select assets (#8004)

fear(mobile): drag to select assets

Co-authored-by: shenlong-tanwen <139912620+shalong-tanwen@users.noreply.github.com>
Co-authored-by: Alex <alex.tran1502@gmail.com>

mobile/lib/modules/home/ui/asset_grid/asset_drag_region.dart

@@ -0,0 +1,223 @@
+// ignore_for_file: library_private_types_in_public_api
+// Based on https://stackoverflow.com/a/52625182
+
+import 'dart:async';
+
+import 'package:collection/collection.dart';
+import 'package:flutter/gestures.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter/rendering.dart';
+
+class AssetDragRegion extends StatefulWidget {
+  final Widget child;
+
+  final void Function(AssetIndex valueKey)? onStart;
+  final void Function(AssetIndex valueKey)? onAssetEnter;
+  final void Function()? onEnd;
+  final void Function()? onScrollStart;
+  final void Function(ScrollDirection direction)? onScroll;
+
+  const AssetDragRegion({
+    super.key,
+    required this.child,
+    this.onStart,
+    this.onAssetEnter,
+    this.onEnd,
+    this.onScrollStart,
+    this.onScroll,
+  });
+  @override
+  State createState() => _AssetDragRegionState();
+}
+
+class _AssetDragRegionState extends State<AssetDragRegion> {
+  late AssetIndex? assetUnderPointer;
+  late AssetIndex? anchorAsset;
+
+  // Scroll related state
+  static const double scrollOffset = 0.10;
+  double? topScrollOffset;
+  double? bottomScrollOffset;
+  Timer? scrollTimer;
+  late bool scrollNotified;
+
+  @override
+  void initState() {
+    super.initState();
+    assetUnderPointer = null;
+    anchorAsset = null;
+    scrollNotified = false;
+  }
+
+  @override
+  void didChangeDependencies() {
+    super.didChangeDependencies();
+    topScrollOffset = null;
+    bottomScrollOffset = null;
+  }
+
+  @override
+  void dispose() {
+    scrollTimer?.cancel();
+    super.dispose();
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return RawGestureDetector(
+      gestures: {
+        _CustomLongPressGestureRecognizer: GestureRecognizerFactoryWithHandlers<
+            _CustomLongPressGestureRecognizer>(
+          () => _CustomLongPressGestureRecognizer(),
+          _registerCallbacks,
+        ),
+      },
+      child: widget.child,
+    );
+  }
+
+  void _registerCallbacks(_CustomLongPressGestureRecognizer recognizer) {
+    recognizer.onLongPressMoveUpdate = (details) => _onLongPressMove(details);
+    recognizer.onLongPressStart = (details) => _onLongPressStart(details);
+    recognizer.onLongPressUp = _onLongPressEnd;
+    recognizer.onLongPressCancel = _onLongPressEnd;
+  }
+
+  AssetIndex? _getValueKeyAtPositon(Offset position) {
+    final box = context.findAncestorRenderObjectOfType<RenderBox>();
+    if (box == null) return null;
+
+    final hitTestResult = BoxHitTestResult();
+    final local = box.globalToLocal(position);
+    if (!box.hitTest(hitTestResult, position: local)) return null;
+
+    return (hitTestResult.path
+            .firstWhereOrNull((hit) => hit.target is _AssetIndexProxy)
+            ?.target as _AssetIndexProxy?)
+        ?.index;
+  }
+
+  void _onLongPressStart(LongPressStartDetails event) {
+    /// Calculate widget height and scroll offset when long press starting instead of in [initState]
+    /// or [didChangeDependencies] as the grid might still be rendering into view to get the actual size
+    final height = context.size?.height;
+    if (height != null &&
+        (topScrollOffset == null || bottomScrollOffset == null)) {
+      topScrollOffset = height * scrollOffset;
+      bottomScrollOffset = height - topScrollOffset!;
+    }
+
+    final initialHit = _getValueKeyAtPositon(event.globalPosition);
+    anchorAsset = initialHit;
+    if (initialHit == null) return;
+
+    if (anchorAsset != null) {
+      widget.onStart?.call(anchorAsset!);
+    }
+  }
+
+  void _onLongPressEnd() {
+    scrollNotified = false;
+    scrollTimer?.cancel();
+    widget.onEnd?.call();
+  }
+
+  void _onLongPressMove(LongPressMoveUpdateDetails event) {
+    if (anchorAsset == null) return;
+    if (topScrollOffset == null || bottomScrollOffset == null) return;
+
+    final currentDy = event.localPosition.dy;
+
+    if (currentDy > bottomScrollOffset!) {
+      scrollTimer ??= Timer.periodic(
+        const Duration(milliseconds: 50),
+        (_) => widget.onScroll?.call(ScrollDirection.forward),
+      );
+    } else if (currentDy < topScrollOffset!) {
+      scrollTimer ??= Timer.periodic(
+        const Duration(milliseconds: 50),
+        (_) => widget.onScroll?.call(ScrollDirection.reverse),
+      );
+    } else {
+      scrollTimer?.cancel();
+      scrollTimer = null;
+    }
+
+    final currentlyTouchingAsset = _getValueKeyAtPositon(event.globalPosition);
+    if (currentlyTouchingAsset == null) return;
+
+    if (assetUnderPointer != currentlyTouchingAsset) {
+      if (!scrollNotified) {
+        scrollNotified = true;
+        widget.onScrollStart?.call();
+      }
+
+      widget.onAssetEnter?.call(currentlyTouchingAsset);
+      assetUnderPointer = currentlyTouchingAsset;
+    }
+  }
+}
+
+class _CustomLongPressGestureRecognizer extends LongPressGestureRecognizer {
+  @override
+  void rejectGesture(int pointer) {
+    acceptGesture(pointer);
+  }
+}
+
+// ignore: prefer-single-widget-per-file
+class AssetIndexWrapper extends SingleChildRenderObjectWidget {
+  final int rowIndex;
+  final int sectionIndex;
+
+  const AssetIndexWrapper({
+    required Widget super.child,
+    required this.rowIndex,
+    required this.sectionIndex,
+    super.key,
+  });
+
+  @override
+  _AssetIndexProxy createRenderObject(BuildContext context) {
+    return _AssetIndexProxy(
+      index: AssetIndex(rowIndex: rowIndex, sectionIndex: sectionIndex),
+    );
+  }
+
+  @override
+  void updateRenderObject(
+    BuildContext context,
+    _AssetIndexProxy renderObject,
+  ) {
+    renderObject.index =
+        AssetIndex(rowIndex: rowIndex, sectionIndex: sectionIndex);
+  }
+}
+
+class _AssetIndexProxy extends RenderProxyBox {
+  AssetIndex index;
+
+  _AssetIndexProxy({
+    required this.index,
+  });
+}
+
+class AssetIndex {
+  final int rowIndex;
+  final int sectionIndex;
+
+  const AssetIndex({
+    required this.rowIndex,
+    required this.sectionIndex,
+  });
+
+  @override
+  bool operator ==(covariant AssetIndex other) {
+    if (identical(this, other)) return true;
+
+    return other.rowIndex == rowIndex && other.sectionIndex == sectionIndex;
+  }
+
+  @override
+  int get hashCode => rowIndex.hashCode ^ sectionIndex.hashCode;
+}

mobile/lib/modules/home/ui/asset_grid/immich_asset_grid_view.dart

@@ -5,12 +5,15 @@ import 'dart:math';
 import 'package:collection/collection.dart';
 import 'package:easy_localization/easy_localization.dart';
 import 'package:flutter/material.dart';
+import 'package:flutter/rendering.dart';
 import 'package:flutter/services.dart';
 import 'package:immich_mobile/extensions/build_context_extensions.dart';
 import 'package:immich_mobile/extensions/collection_extensions.dart';
 import 'package:immich_mobile/modules/asset_viewer/providers/scroll_notifier.provider.dart';
+import 'package:immich_mobile/modules/home/ui/asset_grid/asset_drag_region.dart';
 import 'package:immich_mobile/modules/home/ui/asset_grid/thumbnail_image.dart';
 import 'package:immich_mobile/modules/home/ui/asset_grid/thumbnail_placeholder.dart';
+import 'package:immich_mobile/modules/home/ui/control_bottom_app_bar.dart';
 import 'package:immich_mobile/shared/models/asset.dart';
 import 'package:scrollable_positioned_list/scrollable_positioned_list.dart';
 
@@ -73,6 +76,8 @@ class ImmichAssetGridView extends StatefulWidget {
 
 class ImmichAssetGridViewState extends State<ImmichAssetGridView> {
   final ItemScrollController _itemScrollController = ItemScrollController();
+  final ScrollOffsetController _scrollOffsetController =
+      ScrollOffsetController();
   final ItemPositionsListener _itemPositionsListener =
       ItemPositionsListener.create();
 
@@ -83,6 +88,12 @@ class ImmichAssetGridViewState extends State<ImmichAssetGridView> {
   final Set<Asset> _selectedAssets =
       LinkedHashSet(equals: (a, b) => a.id == b.id, hashCode: (a) => a.id);
 
+  bool _dragging = false;
+  int? _dragAnchorAssetIndex;
+  int? _dragAnchorSectionIndex;
+  final Set<Asset> _draggedAssets =
+      HashSet(equals: (a, b) => a.id == b.id, hashCode: (a) => a.id);
+
   Set<Asset> _getSelectedAssets() {
     return Set.from(_selectedAssets);
   }
@@ -93,20 +104,26 @@ class ImmichAssetGridViewState extends State<ImmichAssetGridView> {
 
   void _selectAssets(List<Asset> assets) {
     setState(() {
+      if (_dragging) {
+        _draggedAssets.addAll(assets);
+      }
       _selectedAssets.addAll(assets);
       _callSelectionListener(true);
     });
   }
 
   void _deselectAssets(List<Asset> assets) {
+    final assetsToDeselect = assets.where(
+      (a) =>
+          widget.canDeselect ||
+          !(widget.preselectedAssets?.contains(a) ?? false),
+    );
+
     setState(() {
-      _selectedAssets.removeAll(
-        assets.where(
-          (a) =>
-              widget.canDeselect ||
-              !(widget.preselectedAssets?.contains(a) ?? false),
-        ),
-      );
+      _selectedAssets.removeAll(assetsToDeselect);
+      if (_dragging) {
+        _draggedAssets.removeAll(assetsToDeselect);
+      }
       _callSelectionListener(_selectedAssets.isNotEmpty);
     });
   }
@@ -114,6 +131,10 @@ class ImmichAssetGridViewState extends State<ImmichAssetGridView> {
   void _deselectAll() {
     setState(() {
       _selectedAssets.clear();
+      _dragAnchorAssetIndex = null;
+      _dragAnchorSectionIndex = null;
+      _draggedAssets.clear();
+      _dragging = false;
       if (!widget.canDeselect &&
           widget.preselectedAssets != null &&
           widget.preselectedAssets!.isNotEmpty) {
@@ -142,6 +163,7 @@ class ImmichAssetGridViewState extends State<ImmichAssetGridView> {
       showStorageIndicator: widget.showStorageIndicator,
       selectedAssets: _selectedAssets,
       selectionActive: widget.selectionActive,
+      sectionIndex: index,
       section: section,
       margin: widget.margin,
       renderList: widget.renderList,
@@ -199,6 +221,7 @@ class ImmichAssetGridViewState extends State<ImmichAssetGridView> {
       itemBuilder: _itemBuilder,
       itemPositionsListener: _itemPositionsListener,
       itemScrollController: _itemScrollController,
+      scrollOffsetController: _scrollOffsetController,
       itemCount: widget.renderList.elements.length +
           (widget.topWidget != null ? 1 : 0),
       addRepaintBoundaries: true,
@@ -253,6 +276,7 @@ class ImmichAssetGridViewState extends State<ImmichAssetGridView> {
     if (widget.visibleItemsListener != null) {
       _itemPositionsListener.itemPositions.removeListener(_positionListener);
     }
+    _itemPositionsListener.itemPositions.removeListener(_hapticsListener);
     super.dispose();
   }
 
@@ -308,6 +332,107 @@ class ImmichAssetGridViewState extends State<ImmichAssetGridView> {
     );
   }
 
+  void _setDragStartIndex(AssetIndex index) {
+    setState(() {
+      _dragAnchorAssetIndex = index.rowIndex;
+      _dragAnchorSectionIndex = index.sectionIndex;
+      _dragging = true;
+    });
+  }
+
+  void _stopDrag() {
+    setState(() {
+      _dragging = false;
+      _draggedAssets.clear();
+    });
+  }
+
+  void _dragDragScroll(ScrollDirection direction) {
+    _scrollOffsetController.animateScroll(
+      offset: direction == ScrollDirection.forward ? 175 : -175,
+      duration: const Duration(milliseconds: 125),
+    );
+  }
+
+  void _handleDragAssetEnter(AssetIndex index) {
+    if (_dragAnchorSectionIndex == null || _dragAnchorAssetIndex == null) {
+      return;
+    }
+
+    final dragAnchorSectionIndex = _dragAnchorSectionIndex!;
+    final dragAnchorAssetIndex = _dragAnchorAssetIndex!;
+
+    late final int startSectionIndex;
+    late final int startSectionAssetIndex;
+    late final int endSectionIndex;
+    late final int endSectionAssetIndex;
+
+    if (index.sectionIndex < dragAnchorSectionIndex) {
+      startSectionIndex = index.sectionIndex;
+      startSectionAssetIndex = index.rowIndex;
+      endSectionIndex = dragAnchorSectionIndex;
+      endSectionAssetIndex = dragAnchorAssetIndex;
+    } else if (index.sectionIndex > dragAnchorSectionIndex) {
+      startSectionIndex = dragAnchorSectionIndex;
+      startSectionAssetIndex = dragAnchorAssetIndex;
+      endSectionIndex = index.sectionIndex;
+      endSectionAssetIndex = index.rowIndex;
+    } else {
+      startSectionIndex = dragAnchorSectionIndex;
+      endSectionIndex = dragAnchorSectionIndex;
+
+      // If same section, assign proper start / end asset Index
+      if (dragAnchorAssetIndex < index.rowIndex) {
+        startSectionAssetIndex = dragAnchorAssetIndex;
+        endSectionAssetIndex = index.rowIndex;
+      } else {
+        startSectionAssetIndex = index.rowIndex;
+        endSectionAssetIndex = dragAnchorAssetIndex;
+      }
+    }
+
+    final selectedAssets = <Asset>{};
+    var currentSectionIndex = startSectionIndex;
+    while (currentSectionIndex < endSectionIndex) {
+      final section =
+          widget.renderList.elements.elementAtOrNull(currentSectionIndex);
+      if (section == null) continue;
+
+      final sectionAssets =
+          widget.renderList.loadAssets(section.offset, section.count);
+
+      if (currentSectionIndex == startSectionIndex) {
+        selectedAssets.addAll(
+          sectionAssets.slice(startSectionAssetIndex, sectionAssets.length),
+        );
+      } else {
+        selectedAssets.addAll(sectionAssets);
+      }
+
+      currentSectionIndex += 1;
+    }
+
+    final section = widget.renderList.elements.elementAtOrNull(endSectionIndex);
+    if (section != null) {
+      final sectionAssets =
+          widget.renderList.loadAssets(section.offset, section.count);
+      if (startSectionIndex == endSectionIndex) {
+        selectedAssets.addAll(
+          sectionAssets.slice(startSectionAssetIndex, endSectionAssetIndex + 1),
+        );
+      } else {
+        selectedAssets.addAll(
+          sectionAssets.slice(0, endSectionAssetIndex + 1),
+        );
+      }
+    }
+
+    _deselectAssets(_draggedAssets.toList());
+    _draggedAssets.clear();
+    _draggedAssets.addAll(selectedAssets);
+    _selectAssets(_draggedAssets.toList());
+  }
+
   @override
   Widget build(BuildContext context) {
     return PopScope(
@@ -315,7 +440,16 @@ class ImmichAssetGridViewState extends State<ImmichAssetGridView> {
       onPopInvoked: (didPop) => !didPop ? _deselectAll() : null,
       child: Stack(
         children: [
-          _buildAssetGrid(),
+          AssetDragRegion(
+            onStart: _setDragStartIndex,
+            onAssetEnter: _handleDragAssetEnter,
+            onEnd: _stopDrag,
+            onScroll: _dragDragScroll,
+            onScrollStart: () => WidgetsBinding.instance.addPostFrameCallback(
+              (_) => controlBottomAppBarNotifier.minimize(),
+            ),
+            child: _buildAssetGrid(),
+          ),
           if (widget.showMultiSelectIndicator && widget.selectionActive)
             _buildMultiSelectIndicator(),
         ],
@@ -361,6 +495,7 @@ class _PlaceholderRow extends StatelessWidget {
 /// A section for the render grid
 class _Section extends StatelessWidget {
   final RenderAssetGridElement section;
+  final int sectionIndex;
   final Set<Asset> selectedAssets;
   final bool scrolling;
   final double margin;
@@ -377,6 +512,7 @@ class _Section extends StatelessWidget {
 
   const _Section({
     required this.section,
+    required this.sectionIndex,
     required this.scrolling,
     required this.margin,
     required this.assetsPerRow,
@@ -435,6 +571,8 @@ class _Section extends StatelessWidget {
                     )
                   : _AssetRow(
                       key: ValueKey(i),
+                      rowStartIndex: i * assetsPerRow,
+                      sectionIndex: sectionIndex,
                       assets: assetsToRender.nestedSlice(
                         i * assetsPerRow,
                         min((i + 1) * assetsPerRow, section.count),
@@ -522,6 +660,8 @@ class _Title extends StatelessWidget {
 /// The row of assets
 class _AssetRow extends StatelessWidget {
   final List<Asset> assets;
+  final int rowStartIndex;
+  final int sectionIndex;
   final Set<Asset> selectedAssets;
   final int absoluteOffset;
   final double width;
@@ -539,6 +679,8 @@ class _AssetRow extends StatelessWidget {
 
   const _AssetRow({
     super.key,
+    required this.rowStartIndex,
+    required this.sectionIndex,
     required this.assets,
     required this.absoluteOffset,
     required this.width,
@@ -594,18 +736,22 @@ class _AssetRow extends StatelessWidget {
             bottom: margin,
             right: last ? 0.0 : margin,
           ),
-          child: ThumbnailImage(
-            asset: asset,
-            index: absoluteOffset + index,
-            loadAsset: renderList.loadAsset,
-            totalAssets: renderList.totalAssets,
-            multiselectEnabled: selectionActive,
-            isSelected: isSelectionActive && selectedAssets.contains(asset),
-            onSelect: () => onSelect?.call(asset),
-            onDeselect: () => onDeselect?.call(asset),
-            showStorageIndicator: showStorageIndicator,
-            heroOffset: heroOffset,
-            showStack: showStack,
+          child: AssetIndexWrapper(
+            rowIndex: rowStartIndex + index,
+            sectionIndex: sectionIndex,
+            child: ThumbnailImage(
+              asset: asset,
+              index: absoluteOffset + index,
+              loadAsset: renderList.loadAsset,
+              totalAssets: renderList.totalAssets,
+              multiselectEnabled: selectionActive,
+              isSelected: isSelectionActive && selectedAssets.contains(asset),
+              onSelect: () => onSelect?.call(asset),
+              onDeselect: () => onDeselect?.call(asset),
+              showStorageIndicator: showStorageIndicator,
+              heroOffset: heroOffset,
+              showStack: showStack,
+            ),
           ),
         );
       }).toList(),

mobile/lib/modules/home/ui/control_bottom_app_bar.dart

@@ -1,5 +1,6 @@
 import 'package:easy_localization/easy_localization.dart';
 import 'package:flutter/material.dart';
+import 'package:flutter_hooks/flutter_hooks.dart';
 import 'package:hooks_riverpod/hooks_riverpod.dart';
 import 'package:immich_mobile/extensions/build_context_extensions.dart';
 import 'package:immich_mobile/modules/album/providers/album.provider.dart';
@@ -11,8 +12,17 @@ import 'package:immich_mobile/modules/home/ui/upload_dialog.dart';
 import 'package:immich_mobile/shared/providers/server_info.provider.dart';
 import 'package:immich_mobile/shared/ui/drag_sheet.dart';
 import 'package:immich_mobile/shared/models/album.dart';
+import 'package:immich_mobile/utils/draggable_scroll_controller.dart';
 
-class ControlBottomAppBar extends ConsumerWidget {
+final controlBottomAppBarNotifier = ControlBottomAppBarNotifier();
+
+class ControlBottomAppBarNotifier with ChangeNotifier {
+  void minimize() {
+    notifyListeners();
+  }
+}
+
+class ControlBottomAppBar extends HookConsumerWidget {
   final void Function(bool shareLocal) onShare;
   final void Function()? onFavorite;
   final void Function()? onArchive;
@@ -64,6 +74,25 @@ class ControlBottomAppBar extends ConsumerWidget {
     final albums = ref.watch(albumProvider).where((a) => a.isRemote).toList();
     final sharedAlbums = ref.watch(sharedAlbumProvider);
     const bottomPadding = 0.20;
+    final scrollController = useDraggableScrollController();
+
+    void minimize() {
+      scrollController.animateTo(
+        bottomPadding,
+        duration: const Duration(milliseconds: 300),
+        curve: Curves.easeOut,
+      );
+    }
+
+    useEffect(
+      () {
+        controlBottomAppBarNotifier.addListener(minimize);
+        return () {
+          controlBottomAppBarNotifier.removeListener(minimize);
+        };
+      },
+      [],
+    );
 
     void showForceDeleteDialog(
       Function(bool) deleteCb, {
@@ -242,6 +271,7 @@ class ControlBottomAppBar extends ConsumerWidget {
     }
 
     return DraggableScrollableSheet(
+      controller: scrollController,
       initialChildSize: hasRemote ? 0.35 : bottomPadding,
       minChildSize: bottomPadding,
       maxChildSize: hasRemote ? 0.65 : bottomPadding,