Automatically relayout cells after orientation changed.

AsyncDisplayKit/ASCollectionView.mm

@@ -15,6 +15,7 @@
 #import "ASDisplayNodeInternal.h"
 #import "ASBatchFetching.h"
 #import "UICollectionViewLayout+ASConvenience.h"
+#import "ASInternalHelpers.h"
 
 const static NSUInteger kASCollectionViewAnimationNone = UITableViewRowAnimationNone;
 
@@ -121,6 +122,8 @@ static BOOL _isInterceptedSelector(SEL sel)
   BOOL _implementsInsetSection;
 
   ASBatchContext *_batchContext;
+  
+  BOOL _pendingRelayoutForAllRows;
 }
 
 @property (atomic, assign) BOOL asyncDataSourceLocked;
@@ -168,6 +171,11 @@ static BOOL _isInterceptedSelector(SEL sel)
   
   [self registerClass:[UICollectionViewCell class] forCellWithReuseIdentifier:@"_ASCollectionViewCell"];
   
+  if (ASSystemVersionLessThan8()) {
+    [[UIDevice currentDevice] beginGeneratingDeviceOrientationNotifications];
+    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(deviceOrientationDidChange) name:UIDeviceOrientationDidChangeNotification object:nil];
+  }
+  
   return self;
 }
 
@@ -177,6 +185,11 @@ static BOOL _isInterceptedSelector(SEL sel)
   // This bug might be iOS 7-specific.
   super.delegate  = nil;
   super.dataSource = nil;
+  
+  if (ASSystemVersionLessThan8()) {
+    [[NSNotificationCenter defaultCenter] removeObserver:self];
+    [[UIDevice currentDevice] endGeneratingDeviceOrientationNotifications];
+  }
 }
 
 #pragma mark -
@@ -462,6 +475,32 @@ static BOOL _isInterceptedSelector(SEL sel)
 }
 
 
+#pragma mark -
+#pragma mark Orientation Change Handling
+
+- (void)traitCollectionDidChange:(UITraitCollection *)previousTraitCollection
+{
+  _pendingRelayoutForAllRows = YES;
+}
+
+- (void)deviceOrientationDidChange
+{
+  _pendingRelayoutForAllRows = YES;
+}
+
+- (void)layoutSubviews
+{
+  [super layoutSubviews];
+  
+  if (_pendingRelayoutForAllRows) {
+    _pendingRelayoutForAllRows = NO;
+    [self performBatchAnimated:NO updates:^{
+      [_dataController relayoutAllRows];
+    } completion:nil];
+  }
+}
+
+
 #pragma mark -
 #pragma mark Batch Fetching
 

AsyncDisplayKit/ASTableView.mm

@@ -15,6 +15,7 @@
 #import "ASRangeController.h"
 #import "ASDisplayNodeInternal.h"
 #import "ASBatchFetching.h"
+#import "ASInternalHelpers.h"
 
 //#define LOG(...) NSLog(__VA_ARGS__)
 #define LOG(...)
@@ -131,6 +132,8 @@ static BOOL _isInterceptedSelector(SEL sel)
 
   NSIndexPath *_contentOffsetAdjustmentTopVisibleRow;
   CGFloat _contentOffsetAdjustment;
+
+  BOOL _pendingRelayoutForAllRows;
 }
 
 @property (atomic, assign) BOOL asyncDataSourceLocked;
@@ -183,6 +186,11 @@ void ASPerformBlockWithoutAnimation(BOOL withoutAnimation, void (^block)()) {
   _batchContext = [[ASBatchContext alloc] init];
 
   _automaticallyAdjustsContentOffset = NO;
+  
+  if (ASSystemVersionLessThan8()) {
+    [[UIDevice currentDevice] beginGeneratingDeviceOrientationNotifications];
+    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(deviceOrientationDidChange) name:UIDeviceOrientationDidChangeNotification object:nil];
+  }
 }
 
 - (instancetype)initWithFrame:(CGRect)frame style:(UITableViewStyle)style
@@ -220,6 +228,11 @@ void ASPerformBlockWithoutAnimation(BOOL withoutAnimation, void (^block)()) {
   // This bug might be iOS 7-specific.
   super.delegate  = nil;
   super.dataSource = nil;
+  
+  if (ASSystemVersionLessThan8()) {
+    [[NSNotificationCenter defaultCenter] removeObserver:self];
+    [[UIDevice currentDevice] endGeneratingDeviceOrientationNotifications];
+  }
 }
 
 #pragma mark -
@@ -343,6 +356,31 @@ void ASPerformBlockWithoutAnimation(BOOL withoutAnimation, void (^block)()) {
   [_dataController endUpdatesAnimated:animated completion:completion];
 }
 
+#pragma mark -
+#pragma mark Orientation Change Handling
+
+- (void)traitCollectionDidChange:(UITraitCollection *)previousTraitCollection
+{
+  _pendingRelayoutForAllRows = YES;
+}
+
+- (void)deviceOrientationDidChange
+{
+  _pendingRelayoutForAllRows = YES;
+}
+
+- (void)layoutSubviews
+{
+  [super layoutSubviews];
+  
+  if (_pendingRelayoutForAllRows) {
+    _pendingRelayoutForAllRows = NO;
+    [self beginUpdates];
+    [_dataController relayoutAllRows];
+    [self endUpdates];
+  }
+}
+
 #pragma mark -
 #pragma mark Editing
 

AsyncDisplayKit/Details/ASDataController.h

@@ -154,6 +154,12 @@ typedef NSUInteger ASDataControllerAnimationOptions;
 
 - (void)reloadRowsAtIndexPaths:(NSArray *)indexPaths withAnimationOptions:(ASDataControllerAnimationOptions)animationOptions;
 
+/**
+ * Re-measures all loaded nodes. Used for external relayout (relayout that is caused by a change in constrained size of each and every cell node,
+ * for example, after an orientation change).
+ */
+- (void)relayoutAllRows;
+
 - (void)moveRowAtIndexPath:(NSIndexPath *)indexPath toIndexPath:(NSIndexPath *)newIndexPath withAnimationOptions:(ASDataControllerAnimationOptions)animationOptions;
 
 - (void)reloadDataWithAnimationOptions:(ASDataControllerAnimationOptions)animationOptions completion:(void (^)())completion;

AsyncDisplayKit/Details/ASDataController.mm

@@ -555,6 +555,26 @@ static void *kASSizingQueueContext = &kASSizingQueueContext;
   }];
 }
 
+- (void)relayoutAllRows
+{
+  [self performEditCommandWithBlock:^{
+    ASDisplayNodeAssertMainThread();
+    LOG(@"Edit Command - relayoutRows");
+    [_editingTransactionQueue waitUntilAllOperationsAreFinished];
+    
+    NSArray *indexPaths = ASIndexPathsForMultidimensionalArray(_completedNodes);
+    NSArray *loadedNodes = ASFindElementsInMultidimensionalArrayAtIndexPaths(_completedNodes, indexPaths);
+    
+    for (NSUInteger i = 0; i < loadedNodes.count && i < indexPaths.count; i++) {
+      // TODO: The current implementation does not make use of different constrained sizes per node.
+      CGSize constrainedSize = [_dataSource dataController:self constrainedSizeForNodeAtIndexPath:indexPaths[i]];
+      ASCellNode *node = loadedNodes[i];
+      [node measure:constrainedSize];
+      node.frame = CGRectMake(0.0f, 0.0f, node.calculatedSize.width, node.calculatedSize.height);
+    }
+  }];
+}
+
 - (void)moveRowAtIndexPath:(NSIndexPath *)indexPath toIndexPath:(NSIndexPath *)newIndexPath withAnimationOptions:(ASDataControllerAnimationOptions)animationOptions
 {
   [self performEditCommandWithBlock:^{

AsyncDisplayKit/Private/ASInternalHelpers.h

@@ -24,4 +24,8 @@ CGFloat ASCeilPixelValue(CGFloat f);
 
 CGFloat ASRoundPixelValue(CGFloat f);
 
+BOOL ASSystemVersionLessThan8();
+
+BOOL ASSystemVersionLessThanVersion(NSString *version);
+
 ASDISPLAYNODE_EXTERN_C_END

AsyncDisplayKit/Private/ASInternalHelpers.mm

@@ -61,3 +61,18 @@ CGFloat ASRoundPixelValue(CGFloat f)
 {
   return roundf(f * ASScreenScale()) / ASScreenScale();
 }
+
+BOOL ASSystemVersionLessThan8()
+{
+  static BOOL lessThan8;
+  static dispatch_once_t onceToken;
+  dispatch_once(&onceToken, ^{
+    lessThan8 = ASSystemVersionLessThanVersion(@"8");
+  });
+  return lessThan8;
+}
+
+BOOL ASSystemVersionLessThanVersion(NSString *version)
+{
+  return [[[UIDevice currentDevice] systemVersion] compare:version options:NSNumericSearch] == NSOrderedAscending;
+}