[翻译] AsyncDisplayKit

AsyncDisplayKit

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.

AsyncDisplayKit（异步图形显示）是一个iOS的开源框架，它能改善非常复杂的用户交互卡顿的问题，并使其圆滑。最开始，开发它是用来优化Facebook的Paper应用，以及配合pop的物理引擎动画--当然，它像UIKit Dynamics框架一样高效且设计精美。

Quick start

ASDK is available on CocoaPods. Add the following to your Podfile:

ASDK可以通过CocoaPods安装，添加以下文件到Podfile中：

pod ‘AsyncDisplayKit‘

Import the framework header, or create an Objective-C bridging header if you‘re using Swift:

导入框架的头文件，或者创建Objective-C bridging header，如果你是使用Swift开发：

#import <AsyncDisplayKit/AsyncDisplayKit.h>

AsyncDisplayKit Nodes are a thread-safe abstraction layer over UIViews and CALayers:

AsyncDisplayKit的节点是一个线程安全的抽象layer，覆盖了UIView以及CALayer

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:

你可以通过封装的方式，或者是直接在子线程中实例化一个节点对象 -- 例如，你可以在UIViewController中做如下的操作：

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.

你可以使用ASImageNode以及ASTextNode的继承类来替换UIImageView以及UITextView，或者创建你自己的节点，用以实现你自己的绘制方式，ASTableView就是一个自定义node的UITableView的子类，它可以异步装载cell节点而不阻塞主线程。

Learn more

• Read the Getting Started guide
• Get the sample projects
• Browse the API reference
• Watch the NSLondon talk