1545384c7c
This adds new initializer methods to ASDisplayNode:
```objc
initWithViewBlock:(ASDisplayNodeViewBlock)viewBlock
initWithLayerBlock:(ASDisplayNodeLayerBlock)layerBlock
```
Sometimes a view can't be constructed with `-[initWithViewClass:]` but you want to use it with ASDK, so these new methods provide a way to wrap an existing view in a node.
The API is meant to preserve ASDisplayNode's behavior, so you can still construct and set properties on the node on a background queue before its view is loaded; even though the view was created a priori, it is not considered to be loaded until `node.view` is accessed.
Using the API looks like this:
dispatch_async(backgroundQueue, ^{
ASDisplayNode *node = [ASDisplayNode alloc] initWithViewBlock:^{
// Guaranteed to run on the main queue
UIButton *button = [UIButton buttonWithType:UIButtonTypeSystem];
[button sizeToFit];
node.frame = button.frame;
return button;
}];
// Use `node` as you normally would...
node.backgroundColor = [UIColor redColor];
});
The main thing this bridging API doesn't do (can't do?) is layout. Methods like `-[ASDisplayNode calculateSizeThatFits:]` and `-[ASDisplayNode layout]` cannot delegate to `[UIView sizeThatFits:]` and `[UIView layoutSubviews]` since the UIView methods must run on the main thread. If ASDK were internally asynchronous and could dispatch its layout methods to different threads (sort of like how ASTableView computes its cells' layouts) then we could mark nodes with externally provided views/layers as having "main-queue affinity" and delegate its layout to UIKit.
Test cases are included and all existing tests pass.
AsyncDisplayKit is an iOS framework that keeps even the most complex user interfaces smooth and responsive. It was originally built to make Facebook's Paper possible, and goes hand-in-hand with pop's physics-based animations — but it's just as powerful with UIKit Dynamics and conventional app designs.
Quick start
ASDK is available on CocoaPods. Add the following to your Podfile:
pod 'AsyncDisplayKit'
(ASDK can also be used as a regular static library: Copy the project to your
codebase manually, adding AsyncDisplayKit.xcodeproj to your workspace. Add
libAsyncDisplayKit.a, AssetsLibrary, and Photos to the "Link Binary With
Libraries" build phase. Include -lc++ -ObjC in your project linker flags.)
Import the framework header, or create an Objective-C bridging header if you're using Swift:
#import <AsyncDisplayKit/AsyncDisplayKit.h>
AsyncDisplayKit Nodes are a thread-safe abstraction layer over UIViews and CALayers:
You can construct entire node hierarchies in parallel, or instantiate and size a single node on a background thread — for example, you could do something like this in a UIViewController:
dispatch_async(_backgroundQueue, ^{
ASTextNode *node = [[ASTextNode alloc] init];
node.attributedString = [[NSAttributedString alloc] initWithString:@"hello!"
attributes:nil];
[node measure:CGSizeMake(screenWidth, FLT_MAX)];
node.frame = (CGRect){ CGPointZero, node.calculatedSize };
// self.view isn't a node, so we can only use it on the main thread
dispatch_async(dispatch_get_main_queue(), ^{
[self.view addSubview:node.view];
});
});
AsyncDisplayKit at a glance:
ASImageNodeandASTextNodeare drop-in replacements for UIImageView and UITextView.ASMultiplexImageNodecan load and display progressively higher-quality variants of an image over a slow cell network, letting you quickly show a low-resolution photo while the full size downloads.ASNetworkImageNodeis a simpler, single-image counterpart to the Multiplex node.ASTableViewandASCollectionVieware a node-aware UITableView and UICollectionView, respectively, that can asynchronously preload cell nodes — from loading network data to rendering — all without blocking the main thread.
You can also easily create your own nodes to implement node hierarchies or custom drawing.
Learn more
- Read the Getting Started guide
- Get the sample projects
- Browse the API reference
- Watch the NSLondon talk
Testing
AsyncDisplayKit has extensive unit test coverage. You'll need to run pod install in the root AsyncDisplayKit directory to set up OCMock.
Contributing
See the CONTRIBUTING file for how to help out.
License
AsyncDisplayKit is BSD-licensed. We also provide an additional patent grant.
The files in the /examples directory are licensed under a separate license as specified in each file; documentation is licensed CC-BY-4.0.