Merge pull request #990 from facebook/ASPagerNodeAndCollectionAndTable

[ASPagerNode] New API tweaks.  Support setting delegate + dataSource on ASCollectionNode and ASTableNode without triggering view creation.

Author: appleguy

AsyncDisplayKit.xcodeproj/project.pbxproj

@@ -242,7 +242,7 @@
 		34EFC7771B701D2D00AD841F /* ASStackUnpositionedLayout.h in Headers */ = {isa = PBXBuildFile; fileRef = ACF6ED491B17847A00DA7C62 /* ASStackUnpositionedLayout.h */; };
 		34EFC7781B701D3100AD841F /* ASStackUnpositionedLayout.mm in Sources */ = {isa = PBXBuildFile; fileRef = ACF6ED4A1B17847A00DA7C62 /* ASStackUnpositionedLayout.mm */; };
 		34EFC7791B701D3600AD841F /* ASLayoutSpecUtilities.h in Headers */ = {isa = PBXBuildFile; fileRef = ACF6ED451B17847A00DA7C62 /* ASLayoutSpecUtilities.h */; };
-		3C9C128519E616EF00E942A0 /* ASTableViewTests.m in Sources */ = {isa = PBXBuildFile; fileRef = 3C9C128419E616EF00E942A0 /* ASTableViewTests.m */; settings = {COMPILER_FLAGS = "-fno-objc-arc"; }; };
+		3C9C128519E616EF00E942A0 /* ASTableViewTests.m in Sources */ = {isa = PBXBuildFile; fileRef = 3C9C128419E616EF00E942A0 /* ASTableViewTests.m */; };
 		430E7C8F1B4C23F100697A4C /* ASIndexPath.h in Headers */ = {isa = PBXBuildFile; fileRef = 430E7C8D1B4C23F100697A4C /* ASIndexPath.h */; settings = {ATTRIBUTES = (Public, ); }; };
 		430E7C901B4C23F100697A4C /* ASIndexPath.h in Headers */ = {isa = PBXBuildFile; fileRef = 430E7C8D1B4C23F100697A4C /* ASIndexPath.h */; settings = {ATTRIBUTES = (Public, ); }; };
 		430E7C911B4C23F100697A4C /* ASIndexPath.m in Sources */ = {isa = PBXBuildFile; fileRef = 430E7C8E1B4C23F100697A4C /* ASIndexPath.m */; };

AsyncDisplayKit/ASCollectionNode.h

@@ -17,6 +17,9 @@
 - (instancetype)initWithCollectionViewLayout:(UICollectionViewLayout *)layout;
 - (instancetype)initWithFrame:(CGRect)frame collectionViewLayout:(UICollectionViewLayout *)layout;
 
+@property (weak, nonatomic) id <ASCollectionDelegate>   delegate;
+@property (weak, nonatomic) id <ASCollectionDataSource> dataSource;
+
 @property (nonatomic, readonly) ASCollectionView *view;
 
 /**

AsyncDisplayKit/ASCollectionNode.m

@@ -9,7 +9,19 @@
 #import "ASCollectionNode.h"
 #import "ASDisplayNode+Subclasses.h"
 
-@interface ASCollectionView (Internal)
+@interface _ASCollectionPendingState : NSObject
+@property (weak, nonatomic) id <ASCollectionDelegate>   delegate;
+@property (weak, nonatomic) id <ASCollectionDataSource> dataSource;
+@end
+
+@implementation _ASCollectionPendingState
+@end
+
+@interface ASCollectionNode ()
+@property (nonatomic) _ASCollectionPendingState *pendingState;
+@end
+
+@interface ASCollectionView ()
 - (instancetype)_initWithFrame:(CGRect)frame collectionViewLayout:(UICollectionViewLayout *)layout;
 @end
 
@@ -29,12 +41,77 @@ - (instancetype)initWithCollectionViewLayout:(UICollectionViewLayout *)layout
 
 - (instancetype)initWithFrame:(CGRect)frame collectionViewLayout:(UICollectionViewLayout *)layout
 {
-  if (self = [super initWithViewBlock:^UIView *{ return [[ASCollectionView alloc] _initWithFrame:frame collectionViewLayout:layout]; }]) {
+  ASDisplayNodeViewBlock collectionViewBlock = ^UIView *{
+    return [[ASCollectionView alloc] _initWithFrame:frame collectionViewLayout:layout];
+  };
+  
+  if (self = [super initWithViewBlock:collectionViewBlock]) {
     return self;
   }
   return nil;
 }
 
+- (void)didLoad
+{
+  [super didLoad];
+  
+  if (_pendingState) {
+    _ASCollectionPendingState *pendingState = _pendingState;
+    self.pendingState = nil;
+    
+    ASCollectionView *view = self.view;
+    view.asyncDelegate     = pendingState.delegate;
+    view.asyncDataSource   = pendingState.dataSource;
+  }
+}
+
+- (_ASCollectionPendingState *)pendingState
+{
+  if (!_pendingState && ![self isNodeLoaded]) {
+    self.pendingState = [[_ASCollectionPendingState alloc] init];
+  }
+  ASDisplayNodeAssert(![self isNodeLoaded] || !_pendingState, @"ASCollectionNode should not have a pendingState once it is loaded");
+  return _pendingState;
+}
+
+- (void)setDelegate:(id <ASCollectionDelegate>)delegate
+{
+  if ([self pendingState]) {
+    _pendingState.delegate = delegate;
+  } else {
+    ASDisplayNodeAssert([self isNodeLoaded], @"ASCollectionNode should be loaded if pendingState doesn't exist");
+    self.view.asyncDelegate = delegate;
+  }
+}
+
+- (id <ASCollectionDelegate>)delegate
+{
+  if ([self pendingState]) {
+    return _pendingState.delegate;
+  } else {
+    return self.view.asyncDelegate;
+  }
+}
+
+- (void)setDataSource:(id <ASCollectionDataSource>)dataSource
+{
+  if ([self pendingState]) {
+    _pendingState.dataSource = dataSource;
+  } else {
+    ASDisplayNodeAssert([self isNodeLoaded], @"ASCollectionNode should be loaded if pendingState doesn't exist");
+    self.view.asyncDataSource = dataSource;
+  }
+}
+
+- (id <ASCollectionDataSource>)dataSource
+{
+  if ([self pendingState]) {
+    return _pendingState.dataSource;
+  } else {
+    return self.view.asyncDataSource;
+  }
+}
+
 - (ASCollectionView *)view
 {
   return (ASCollectionView *)[super view];

AsyncDisplayKit/ASCollectionView.h

@@ -15,8 +15,8 @@
 #import <AsyncDisplayKit/ASCollectionViewFlowLayoutInspector.h>
 
 @class ASCellNode;
-@protocol ASCollectionViewDataSource;
-@protocol ASCollectionViewDelegate;
+@protocol ASCollectionDataSource;
+@protocol ASCollectionDelegate;
 @protocol ASCollectionViewLayoutInspecting;
 
 /**
@@ -35,8 +35,8 @@
 - (instancetype)initWithCollectionViewLayout:(UICollectionViewLayout *)layout;
 - (instancetype)initWithFrame:(CGRect)frame collectionViewLayout:(UICollectionViewLayout *)layout;
 
-@property (nonatomic, weak) id<ASCollectionViewDataSource> asyncDataSource;
-@property (nonatomic, weak) id<ASCollectionViewDelegate> asyncDelegate;       // must not be nil
+@property (nonatomic, weak) id<ASCollectionDelegate>   asyncDelegate;
+@property (nonatomic, weak) id<ASCollectionDataSource> asyncDataSource;
 
 /**
  * Tuning parameters for a range type.
@@ -286,7 +286,8 @@
 /**
  * This is a node-based UICollectionViewDataSource.
  */
-@protocol ASCollectionViewDataSource <ASCommonCollectionViewDataSource, NSObject>
+#define ASCollectionViewDataSource ASCollectionDataSource
+@protocol ASCollectionDataSource <ASCommonCollectionViewDataSource, NSObject>
 
 /**
  * Similar to -collectionView:cellForItemAtIndexPath:.
@@ -347,7 +348,8 @@
 /**
  * This is a node-based UICollectionViewDelegate.
  */
-@protocol ASCollectionViewDelegate <ASCommonCollectionViewDelegate, NSObject>
+#define ASCollectionViewDelegate ASCollectionDelegate
+@protocol ASCollectionDelegate <ASCommonCollectionViewDelegate, NSObject>
 
 @optional
 

AsyncDisplayKit/ASPagerNode.h

@@ -8,20 +8,35 @@
 
 #import <AsyncDisplayKit/ASCollectionNode.h>
 
-@protocol ASPagerNodeDataSource;
+@class ASPagerNode;
+@protocol ASPagerNodeDataSource <NSObject>
+// This method replaces -collectionView:numberOfItemsInSection:
+- (NSInteger)numberOfPagesInPagerNode:(ASPagerNode *)pagerNode;
+
+// This method replaces -collectionView:nodeForItemAtIndexPath:
+- (ASCellNode *)pagerNode:(ASPagerNode *)pagerNode nodeAtIndex:(NSInteger)index;
+@end
 
 @interface ASPagerNode : ASCollectionNode
 
-@property (weak, nonatomic) id<ASPagerNodeDataSource> dataSource;
+// Configures a default horizontal, paging flow layout with 0 inter-item spacing.
+- (instancetype)init;
 
-- (void)scrollToPageAtIndex:(NSInteger)index animated:(BOOL)animated;
+// Initializer with custom-configured flow layout properties.
+- (instancetype)initWithFlowLayout:(UICollectionViewFlowLayout *)flowLayout;
 
-@end
+// The underlying ASCollectionView object.
+- (ASCollectionView *)collectionView;
 
-@protocol ASPagerNodeDataSource <NSObject>
+// Delegate is optional, and uses the same protocol as ASCollectionNode.
+// This includes UIScrollViewDelegate as well as most methods from UICollectionViewDelegate, like willDisplay...
+@property (weak, nonatomic) id <ASCollectionDelegate>  delegate;
 
-- (NSInteger)numberOfPagesInPagerNode:(ASPagerNode *)pagerNode;
+// Data Source is required, and uses a different protocol from ASCollectionNode.
+- (void)setDataSource:(id <ASPagerNodeDataSource>)dataSource;
+- (id <ASPagerNodeDataSource>)dataSource;
 
-- (ASCellNode *)pagerNode:(ASPagerNode *)pagerNode nodeAtIndex:(NSInteger)index;
+- (void)scrollToPageAtIndex:(NSInteger)index animated:(BOOL)animated;
+
+@end
 
-@end

AsyncDisplayKit/ASPagerNode.m

@@ -7,16 +7,20 @@
 //
 
 #import "ASPagerNode.h"
+#import "ASDelegateProxy.h"
 
 #import <AsyncDisplayKit/AsyncDisplayKit.h>
 
-@interface ASPagerNode () <ASCollectionViewDataSource, ASCollectionViewDelegateFlowLayout> {
+@interface ASPagerNode () <ASCollectionDataSource, ASCollectionViewDelegateFlowLayout, ASDelegateProxyInterceptor> {
   UICollectionViewFlowLayout *_flowLayout;
+  ASPagerNodeProxy *_proxy;
+  id <ASPagerNodeDataSource> _pagerDataSource;
 }
 
 @end
 
 @implementation ASPagerNode
+@dynamic delegate;
 
 - (instancetype)init
 {
@@ -25,24 +29,55 @@ - (instancetype)init
   flowLayout.minimumInteritemSpacing = 0;
   flowLayout.minimumLineSpacing = 0;
 
+  return [self initWithFlowLayout:flowLayout];
+}
+
+- (instancetype)initWithFlowLayout:(UICollectionViewFlowLayout *)flowLayout
+{
   self = [super initWithCollectionViewLayout:flowLayout];
   if (self != nil) {
     _flowLayout = flowLayout;
   }
   return self;
 }
 
+- (ASCollectionView *)collectionView
+{
+  return self.view;
+}
+
+- (void)setDataSource:(id <ASPagerNodeDataSource>)pagerDataSource
+{
+  if (pagerDataSource != _pagerDataSource) {
+    _pagerDataSource = pagerDataSource;
+    _proxy = pagerDataSource ? [[ASPagerNodeProxy alloc] initWithTarget:pagerDataSource interceptor:self] : nil;
+    super.dataSource = (id <ASCollectionDataSource>)_proxy;
+  }
+}
+
+- (void)proxyTargetHasDeallocated:(ASDelegateProxy *)proxy
+{
+  [self setDataSource:nil];
+}
+
+- (id <ASPagerNodeDataSource>)dataSource
+{
+  return _pagerDataSource;
+}
+
 - (void)didLoad
 {
   [super didLoad];
 
-  self.view.asyncDataSource = self;
-  self.view.asyncDelegate = self;
+  ASCollectionView *cv = self.view;
+  cv.asyncDataSource = self;
+  cv.asyncDelegate = self;
 
-  self.view.pagingEnabled = YES;
-  self.view.allowsSelection = NO;
-  self.view.showsVerticalScrollIndicator = NO;
-  self.view.showsHorizontalScrollIndicator = NO;
+  cv.pagingEnabled = YES;
+  cv.allowsSelection = NO;
+  cv.showsVerticalScrollIndicator = NO;
+  cv.showsHorizontalScrollIndicator = NO;
+  cv.scrollsToTop = NO;
 
   ASRangeTuningParameters preloadParams = { .leadingBufferScreenfuls = 2.0, .trailingBufferScreenfuls = 2.0 };
   ASRangeTuningParameters renderParams = { .leadingBufferScreenfuls = 1.0, .trailingBufferScreenfuls = 1.0 };
@@ -62,14 +97,14 @@ - (void)scrollToPageAtIndex:(NSInteger)index animated:(BOOL)animated
 
 - (ASCellNode *)collectionView:(ASCollectionView *)collectionView nodeForItemAtIndexPath:(NSIndexPath *)indexPath
 {
-  ASDisplayNodeAssert(self.dataSource != nil, @"ASPagerNode must have a data source to load paging nodes");
-  return [self.dataSource pagerNode:self nodeAtIndex:indexPath.item];
+  ASDisplayNodeAssert(_pagerDataSource != nil, @"ASPagerNode must have a data source to load paging nodes");
+  return [_pagerDataSource pagerNode:self nodeAtIndex:indexPath.item];
 }
 
 - (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section
 {
-  ASDisplayNodeAssert(self.dataSource != nil, @"ASPagerNode must have a data source to load paging nodes");
-  return [self.dataSource numberOfPagesInPagerNode:self];
+  ASDisplayNodeAssert(_pagerDataSource != nil, @"ASPagerNode must have a data source to load paging nodes");
+  return [_pagerDataSource numberOfPagesInPagerNode:self];
 }
 
 - (ASSizeRange)collectionView:(ASCollectionView *)collectionView constrainedSizeForNodeAtIndexPath:(NSIndexPath *)indexPath

AsyncDisplayKit/ASTableNode.h

@@ -14,8 +14,13 @@
  */
 @interface ASTableNode : ASDisplayNode
 
-- (instancetype)initWithStyle:(UITableViewStyle)style NS_DESIGNATED_INITIALIZER;
+- (instancetype)init; // UITableViewStylePlain
+- (instancetype)initWithStyle:(UITableViewStyle)style;
 
 @property (nonatomic, readonly) ASTableView *view;
 
+// These properties can be set without triggering the view to be created, so it's fine to set them in -init.
+@property (weak, nonatomic) id <ASTableDelegate>   delegate;
+@property (weak, nonatomic) id <ASTableDataSource> dataSource;
+
 @end