[ASTableView] Add Support for Interactive Reordering (#2221)

facebookarchive · Sep 15, 2016 · ad17f61 · ad17f61
1 parent d9a16f2
commit ad17f61
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Showing 6 changed files with 55 additions and 0 deletions.
diff --git a/AsyncDisplayKit/ASTableView.mm b/AsyncDisplayKit/ASTableView.mm
@@ -146,6 +146,8 @@ @interface ASTableView () <ASRangeControllerDataSource, ASRangeControllerDelegat
     unsigned int asyncDataSourceNumberOfSectionsInTableView:1;
     unsigned int asyncDataSourceTableViewNodeBlockForRowAtIndexPath:1;
     unsigned int asyncDataSourceTableViewNodeForRowAtIndexPath:1;
+    unsigned int asyncDataSourceTableViewCanMoveRowAtIndexPath:1;
+    unsigned int asyncDataSourceTableViewMoveRowAtIndexPath:1;
   } _asyncDataSourceFlags;
 }
 
@@ -301,6 +303,8 @@ - (void)setAsyncDataSource:(id<ASTableViewDataSource>)asyncDataSource
     _asyncDataSourceFlags.asyncDataSourceNumberOfSectionsInTableView = [_asyncDataSource respondsToSelector:@selector(numberOfSectionsInTableView:)];
     _asyncDataSourceFlags.asyncDataSourceTableViewNodeForRowAtIndexPath = [_asyncDataSource respondsToSelector:@selector(tableView:nodeForRowAtIndexPath:)];
     _asyncDataSourceFlags.asyncDataSourceTableViewNodeBlockForRowAtIndexPath = [_asyncDataSource respondsToSelector:@selector(tableView:nodeBlockForRowAtIndexPath:)];
+    _asyncDataSourceFlags.asyncDataSourceTableViewCanMoveRowAtIndexPath = [_asyncDataSource respondsToSelector:@selector(tableView:canMoveRowAtIndexPath:)];
+    _asyncDataSourceFlags.asyncDataSourceTableViewMoveRowAtIndexPath = [_asyncDataSource respondsToSelector:@selector(tableView:moveRowAtIndexPath:toIndexPath:)];
 
     // Data source must implement tableView:nodeBlockForRowAtIndexPath: or tableView:nodeForRowAtIndexPath:
     ASDisplayNodeAssertTrue(_asyncDataSourceFlags.asyncDataSourceTableViewNodeBlockForRowAtIndexPath || _asyncDataSourceFlags.asyncDataSourceTableViewNodeForRowAtIndexPath);
@@ -660,6 +664,24 @@ - (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger
   return [_dataController numberOfRowsInSection:section];
 }
 
+- (BOOL)tableView:(UITableView *)tableView canMoveRowAtIndexPath:(NSIndexPath *)indexPath
+{
+  if (_asyncDataSourceFlags.asyncDataSourceTableViewCanMoveRowAtIndexPath) {
+    return [_asyncDataSource tableView:self canMoveRowAtIndexPath:indexPath];
+  } else {
+    return NO;
+  }
+}
+
+- (void)tableView:(UITableView *)tableView moveRowAtIndexPath:(NSIndexPath *)sourceIndexPath toIndexPath:(NSIndexPath *)destinationIndexPath
+{
+  if (_asyncDataSourceFlags.asyncDataSourceTableViewMoveRowAtIndexPath) {
+    [_asyncDataSource tableView:self moveRowAtIndexPath:sourceIndexPath toIndexPath:destinationIndexPath];
+  }
+  // Move node after informing data source in case they call nodeAtIndexPath:
+  [_dataController moveCompletedNodeAtIndexPath:sourceIndexPath toIndexPath:destinationIndexPath];
+}
+
 - (void)tableView:(UITableView *)tableView willDisplayCell:(_ASTableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath
 {
   _pendingVisibleIndexPath = indexPath;

diff --git a/AsyncDisplayKit/Details/ASDataController.h b/AsyncDisplayKit/Details/ASDataController.h
@@ -188,6 +188,14 @@ FOUNDATION_EXPORT NSString * const ASDataControllerRowNodeKind;
  */
 - (NSArray<NSArray <ASCellNode *> *> *)completedNodes;
 
+/**
+ * Immediately move this item. This is called by ASTableView when the user has finished an interactive
+ * item move and the table view is requesting a model update.
+ * 
+ * This must be called on the main thread.
+ */
+- (void)moveCompletedNodeAtIndexPath:(NSIndexPath *)indexPath toIndexPath:(NSIndexPath *)newIndexPath;
+
 @end
 
 NS_ASSUME_NONNULL_END
diff --git a/AsyncDisplayKit/Details/ASDataController.mm b/AsyncDisplayKit/Details/ASDataController.mm
@@ -898,6 +898,13 @@ - (NSArray *)completedNodes
   return _externalCompletedNodes ? : _completedNodes[ASDataControllerRowNodeKind];
 }
 
+- (void)moveCompletedNodeAtIndexPath:(NSIndexPath *)indexPath toIndexPath:(NSIndexPath *)newIndexPath
+{
+  ASDisplayNodeAssertMainThread();
+  ASMoveElementInTwoDimensionalArray(_externalCompletedNodes, indexPath, newIndexPath);
+  ASMoveElementInTwoDimensionalArray(_completedNodes[ASDataControllerRowNodeKind], indexPath, newIndexPath);
+}
+
 #pragma mark - Dealloc
 
 - (void)dealloc

diff --git a/AsyncDisplayKit/Details/ASDelegateProxy.m b/AsyncDisplayKit/Details/ASDelegateProxy.m
@@ -25,6 +25,10 @@ - (BOOL)interceptsSelector:(SEL)selector
           // handled by ASRangeController
           selector == @selector(numberOfSectionsInTableView:) ||
           selector == @selector(tableView:numberOfRowsInSection:) ||
+
+          // reordering support
+          selector == @selector(tableView:canMoveRowAtIndexPath:) ||
+          selector == @selector(tableView:moveRowAtIndexPath:toIndexPath:) ||
 
           // used for ASCellNode visibility
           selector == @selector(scrollViewDidScroll:) ||

diff --git a/AsyncDisplayKit/Private/ASMultidimensionalArrayUtils.h b/AsyncDisplayKit/Private/ASMultidimensionalArrayUtils.h
@@ -51,6 +51,11 @@ extern NSArray *ASFindElementsInMultidimensionalArrayAtIndexPaths(NSMutableArray
  */
 extern NSArray *ASIndexPathsForMultidimensionalArrayAtIndexSet(NSArray *multidimensionalArray, NSIndexSet *indexSet);
 
+/**
+ * Moves the object at `sourceIndexPath` to `destinationIndexPath`.
+ */
+extern void ASMoveElementInTwoDimensionalArray(NSMutableArray *mutableArray, NSIndexPath *sourceIndexPath, NSIndexPath *destinationIndexPath);
+
 /**
  * Return the index paths of the given multidimensional array that are present in the given index paths array.
  */

diff --git a/AsyncDisplayKit/Private/ASMultidimensionalArrayUtils.mm b/AsyncDisplayKit/Private/ASMultidimensionalArrayUtils.mm
@@ -182,6 +182,15 @@ void ASDeleteElementsInMultidimensionalArrayAtIndexPaths(NSMutableArray *mutable
   return res;
 }
 
+void ASMoveElementInTwoDimensionalArray(NSMutableArray *mutableArray, NSIndexPath *sourceIndexPath, NSIndexPath *destinationIndexPath)
+{
+  NSMutableArray *oldSection = mutableArray[sourceIndexPath.section];
+  NSInteger oldItem = sourceIndexPath.item;
+  id object = oldSection[oldItem];
+  [oldSection removeObjectAtIndex:oldItem];
+  [mutableArray[destinationIndexPath.section] insertObject:object atIndex:destinationIndexPath.item];
+}
+
 NSArray<NSIndexPath *> *ASIndexPathsInMultidimensionalArrayIntersectingIndexPaths(NSArray *multidimensionalArray, NSArray<NSIndexPath *> *indexPaths)
 {
   NSMutableArray *res = [NSMutableArray array];