Add scrollToItem: Method to Node, Handle Section Index Paths (#2462)

* Add scrollToItem: method to node, handle section index paths

* Update ASPagerNode.mm to use the node version

* Add some docs

AsyncDisplayKit/ASCollectionNode.h

@@ -136,6 +136,17 @@ NS_ASSUME_NONNULL_BEGIN
  */
 - (void)setTuningParameters:(ASRangeTuningParameters)tuningParameters forRangeMode:(ASLayoutRangeMode)rangeMode rangeType:(ASLayoutRangeType)rangeType;
 
+/**
+ * Scrolls the collection to the given item.
+ *
+ * @param indexPath The index path of the item.
+ * @param scrollPosition Where the item should end up after the scroll.
+ * @param animated Whether the scroll should be animated or not.
+ *
+ * This method must be called on the main thread.
+ */
+- (void)scrollToItemAtIndexPath:(NSIndexPath *)indexPath atScrollPosition:(UICollectionViewScrollPosition)scrollPosition animated:(BOOL)animated;
+
 #pragma mark - Editing
 
 /**

AsyncDisplayKit/ASCollectionNode.mm

@@ -335,6 +335,20 @@
   [self.view deselectItemAtIndexPath:indexPath animated:animated];
 }
 
+- (void)scrollToItemAtIndexPath:(NSIndexPath *)indexPath atScrollPosition:(UICollectionViewScrollPosition)scrollPosition animated:(BOOL)animated
+{
+  ASDisplayNodeAssertMainThread();
+  ASCollectionView *collectionView = self.view;
+
+  indexPath = [collectionView convertIndexPathFromCollectionNode:indexPath waitingIfNeeded:YES];
+
+  if (indexPath != nil) {
+    [collectionView scrollToItemAtIndexPath:indexPath atScrollPosition:scrollPosition animated:animated];
+  } else {
+    NSLog(@"Failed to scroll to item at index path %@ because the item never reached the view.", indexPath);
+  }
+}
+
 #pragma mark - Querying Data
 
 - (void)reloadDataInitiallyIfNeeded

AsyncDisplayKit/ASCollectionView.h

@@ -205,6 +205,15 @@ NS_ASSUME_NONNULL_BEGIN
  */
 - (void)setTuningParameters:(ASRangeTuningParameters)tuningParameters forRangeMode:(ASLayoutRangeMode)rangeMode rangeType:(ASLayoutRangeType)rangeType ASDISPLAYNODE_DEPRECATED_MSG("Use ASCollectionNode method instead.");
 
+/**
+ * Scrolls the collection to the given item.
+ *
+ * @param indexPath The index path of the item.
+ * @param scrollPosition Where the row should end up after the scroll.
+ * @param animated Whether the scroll should be animated or not.
+ */
+- (void)scrollToItemAtIndexPath:(NSIndexPath *)indexPath atScrollPosition:(UICollectionViewScrollPosition)scrollPosition animated:(BOOL)animated ASDISPLAYNODE_DEPRECATED_MSG("Use ASCollectionNode method instead.");
+
 /**
  *  Perform a batch of updates asynchronously, optionally disabling all animations in the batch. This method must be called from the main thread.
  *  The asyncDataSource must be updated to reflect the changes before the update block completes.

AsyncDisplayKit/ASCollectionView.mm

@@ -555,6 +555,11 @@ static NSString * const kCellReuseIdentifier = @"_ASCollectionViewCell";
 
 - (NSIndexPath *)convertIndexPathFromCollectionNode:(NSIndexPath *)indexPath waitingIfNeeded:(BOOL)wait
 {
+  // If this is a section index path, we don't currently have a method
+  // to do a mapping.
+  if (indexPath.item == NSNotFound) {
+    return indexPath;
+  } else {
     ASCellNode *node = [_dataController nodeAtIndexPath:indexPath];
     NSIndexPath *viewIndexPath = [self indexPathForNode:node];
     if (viewIndexPath == nil && wait) {
@@ -562,12 +567,19 @@ static NSString * const kCellReuseIdentifier = @"_ASCollectionViewCell";
       viewIndexPath = [self indexPathForNode:node];
     }
     return viewIndexPath;
+  }
 }
 
 - (NSIndexPath *)convertIndexPathToCollectionNode:(NSIndexPath *)indexPath
 {
+  // If this is a section index path, we don't currently have a method
+  // to do a mapping.
+  if (indexPath.item == NSNotFound) {
+    return indexPath;
+  } else {
     ASCellNode *node = [self nodeForItemAtIndexPath:indexPath];
     return [_dataController indexPathForNode:node];
+  }
 }
 
 - (ASCellNode *)supplementaryNodeForElementKind:(NSString *)elementKind atIndexPath:(NSIndexPath *)indexPath
@@ -596,23 +608,6 @@ static NSString * const kCellReuseIdentifier = @"_ASCollectionViewCell";
   return visibleNodes;
 }
 
-/**
- * TODO: This method was built when the distinction between data source
- * index paths and view index paths was unclear. For compatibility, it
- * still expects data source index paths for the time being.
- */
-- (void)scrollToItemAtIndexPath:(NSIndexPath *)indexPath atScrollPosition:(UICollectionViewScrollPosition)scrollPosition animated:(BOOL)animated
-{
-  ASDisplayNodeAssertMainThread();
-
-  NSIndexPath *viewIndexPath = [self convertIndexPathFromCollectionNode:indexPath waitingIfNeeded:YES];
-  if (viewIndexPath != nil) {
-    [super scrollToItemAtIndexPath:viewIndexPath atScrollPosition:scrollPosition animated:animated];
-  } else {
-    NSLog(@"Warning: Ignoring request to scroll to item at index path %@ because the item did not reach the collection view.", indexPath);
-  }
-}
-
 /**
  * TODO: This method was built when the distinction between data source
  * index paths and view index paths was unclear. For compatibility, it

AsyncDisplayKit/ASPagerNode.m

@@ -101,7 +101,7 @@
 - (void)scrollToPageAtIndex:(NSInteger)index animated:(BOOL)animated
 {
   NSIndexPath *indexPath = [NSIndexPath indexPathForItem:index inSection:0];
-  [self.view scrollToItemAtIndexPath:indexPath atScrollPosition:UICollectionViewScrollPositionLeft animated:animated];
+  [self scrollToItemAtIndexPath:indexPath atScrollPosition:UICollectionViewScrollPositionLeft animated:animated];
 }
 
 - (ASCellNode *)nodeForPageAtIndex:(NSInteger)index

AsyncDisplayKit/ASTableNode.h

@@ -104,6 +104,17 @@ NS_ASSUME_NONNULL_BEGIN
  */
 - (void)setTuningParameters:(ASRangeTuningParameters)tuningParameters forRangeMode:(ASLayoutRangeMode)rangeMode rangeType:(ASLayoutRangeType)rangeType;
 
+/**
+ * Scrolls the table to the given row.
+ *
+ * @param indexPath The index path of the row.
+ * @param scrollPosition Where the row should end up after the scroll.
+ * @param animated Whether the scroll should be animated or not.
+ *
+ * This method must be called on the main thread.
+ */
+- (void)scrollToRowAtIndexPath:(NSIndexPath *)indexPath atScrollPosition:(UITableViewScrollPosition)scrollPosition animated:(BOOL)animated;
+
 /**
  * Reload everything from scratch, destroying the working range and all cached nodes.
  *

AsyncDisplayKit/ASTableNode.mm

@@ -359,6 +359,20 @@ ASEnvironmentCollectionTableSetEnvironmentState(_environmentStateLock)
   [self.view deselectRowAtIndexPath:indexPath animated:animated];
 }
 
+- (void)scrollToRowAtIndexPath:(NSIndexPath *)indexPath atScrollPosition:(UITableViewScrollPosition)scrollPosition animated:(BOOL)animated
+{
+  ASDisplayNodeAssertMainThread();
+  ASTableView *tableView = self.view;
+
+  indexPath = [tableView convertIndexPathFromTableNode:indexPath waitingIfNeeded:YES];
+
+  if (indexPath != nil) {
+    [tableView scrollToRowAtIndexPath:indexPath atScrollPosition:scrollPosition animated:animated];
+  } else {
+    NSLog(@"Failed to scroll to row at index path %@ because the row never reached the view.", indexPath);
+  }
+}
+
 #pragma mark - Querying Data
 
 - (void)reloadDataInitiallyIfNeeded

AsyncDisplayKit/ASTableView.h

@@ -124,6 +124,15 @@ NS_ASSUME_NONNULL_BEGIN
  */
 - (void)setTuningParameters:(ASRangeTuningParameters)tuningParameters forRangeMode:(ASLayoutRangeMode)rangeMode rangeType:(ASLayoutRangeType)rangeType ASDISPLAYNODE_DEPRECATED_MSG("Use ASTableNode method instead.");
 
+/**
+ * Scrolls the table to the given row.
+ *
+ * @param indexPath The index path of the row.
+ * @param scrollPosition Where the row should end up after the scroll.
+ * @param animated Whether the scroll should be animated or not.
+ */
+- (void)scrollToRowAtIndexPath:(NSIndexPath *)indexPath atScrollPosition:(UITableViewScrollPosition)scrollPosition animated:(BOOL)animated ASDISPLAYNODE_DEPRECATED_MSG("Use ASTableNode method instead.");
+
 /**
  * Similar to -visibleCells.
  *

AsyncDisplayKit/ASTableView.mm

@@ -464,14 +464,26 @@ static NSString * const kCellReuseIdentifier = @"_ASTableViewCell";
 
 - (NSIndexPath *)convertIndexPathFromTableNode:(NSIndexPath *)indexPath waitingIfNeeded:(BOOL)wait
 {
+  // If this is a section index path, we don't currently have a method
+  // to do a mapping.
+  if (indexPath.row == NSNotFound) {
+    return indexPath;
+  } else {
     ASCellNode *node = [_dataController nodeAtIndexPath:indexPath];
     return [self indexPathForNode:node waitingIfNeeded:wait];
+  }
 }
 
 - (NSIndexPath *)convertIndexPathToTableNode:(NSIndexPath *)indexPath
 {
+  // If this is a section index path, we don't currently have a method
+  // to do a mapping.
+  if (indexPath.row == NSNotFound) {
+    return indexPath;
+  } else {
     ASCellNode *node = [self nodeForRowAtIndexPath:indexPath];
     return [_dataController indexPathForNode:node];
+  }
 }
 
 - (NSIndexPath *)indexPathForNode:(ASCellNode *)cellNode
@@ -528,25 +540,6 @@ static NSString * const kCellReuseIdentifier = @"_ASTableViewCell";
   [_dataController waitUntilAllUpdatesAreCommitted];
 }
 
-/**
- * TODO: This method was built when the distinction between data source
- * index paths and view index paths was unclear. For compatibility, it
- * still expects data source index paths for the time being.
- * When the behavior is changed (to use the view index path directly)
- * we should also remove the @c convertIndexPathFromTableNode: method.
- */
-- (void)scrollToRowAtIndexPath:(NSIndexPath *)indexPath atScrollPosition:(UITableViewScrollPosition)scrollPosition animated:(BOOL)animated
-{
-  ASDisplayNodeAssertMainThread();
-
-  indexPath = [self convertIndexPathFromTableNode:indexPath waitingIfNeeded:YES];
-  if (indexPath != nil) {
-    [super scrollToRowAtIndexPath:indexPath atScrollPosition:scrollPosition animated:animated];
-  } else {
-    NSLog(@"Warning: Ignoring request to scroll to row at index path %@ because the item did not reach the table view.", indexPath);
-  }
-}
-
 /**
  * TODO: This method was built when the distinction between data source
  * index paths and view index paths was unclear. For compatibility, it

AsyncDisplayKit/ASTableViewInternal.h

@@ -37,4 +37,12 @@
 /// Set YES and we'll log every time we call [super insertRows…] etc
 @property (nonatomic) BOOL test_enableSuperUpdateCallLogging;
 
+/**
+ * Attempt to get the view-layer index path for the row with the given index path.
+ *
+ * @param indexPath The index path of the row.
+ * @param wait If the item hasn't reached the view yet, this attempts to wait for updates to commit.
+ */
+- (NSIndexPath *)convertIndexPathFromTableNode:(NSIndexPath *)indexPath waitingIfNeeded:(BOOL)wait;
+
 @end

AsyncDisplayKit/Details/ASCollectionInternal.h

@@ -25,6 +25,15 @@ NS_ASSUME_NONNULL_BEGIN
 @property (nonatomic, weak, readwrite) ASCollectionNode *collectionNode;
 @property (nonatomic, strong, readonly) ASDataController *dataController;
 @property (nonatomic, strong, readonly) ASRangeController *rangeController;
+
+/**
+ * Attempt to get the view-layer index path for the item with the given index path.
+ *
+ * @param indexPath The index path of the item.
+ * @param wait If the item hasn't reached the view yet, this attempts to wait for updates to commit.
+ */
+- (nullable NSIndexPath *)convertIndexPathFromCollectionNode:(NSIndexPath *)indexPath waitingIfNeeded:(BOOL)wait;
+
 @end
 
 NS_ASSUME_NONNULL_END