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ASDISPLAYNODE_DELAY_DISPLAY unconditionally delays *all* attempts to execute display blocks, even those that have been cancelled. Fix that. The DELAY_DISPLAY debugging tool is intended to simulate the effect of expensive draw calls -- it lets you test your app's behaviour under conditions potentially even worse than an iPhone 4. Unfortunately, the current simulation is unusably incorrect, as can be demonstrated by repeatedly scrolling up and down in the Kittens example project. ASRangeController enqueues asynchronous display of ASTableView cell nodes when they enter the working range, and suspends their display when they exit. On a slow device, this performs as desired, limiting expensive display computation to the space of the working range. In the DELAY_DISPLAY simulation, the suspended displays are as expensive as the executed ones, so ASRangeController becomes unusably slow.
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 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_sync(dispatch_get_main_queue(), ^{
[self.view addSubview:node.view];
});
});
You can use ASImageNode and ASTextNode as drop-in replacements for
UIImageView and UITextView, or create your own
nodes
to implement node hierarchies or custom drawing. ASTableView is a node-aware
UITableView subclass that can asynchronously preload cell nodes without
blocking the main thread.
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.