是绑定widget 框架和Flutter 引擎的桥梁 classWidgetsFlutterBinding extends BindingBase with GestureBinding,SchedulerBinding,ServicesBinding,PaintingBinding,SemanticsBinding,RendererBinding,WidgetsBinding{static WidgetsBindingensureInitialized(){if(WidgetsBinding._instance==null)WidgetsFlutterBinding();returnWidgetsBinding.instan...
进入runApp 方法,其中 WidgetsFlutterBinding 是一个桥接类,它是连接底层 Flutter engine SDK 的桥梁,用来接收处理 Flutter engine 传递过来的消息,Flutter engine 负责布局、绘制、平台消息、手势等功能。 WidgetsFlutterBinding 继承自 BindingBase,BindingBase mixin 了7个类:GestureBinding, ServicesBinding, SchedulerBindin...
Flutter入口函数runApp的注释可以提供证明: Calling [runApp] again will detach the previous root widget from the screen and attach the given widget in its place. The new widget tree is compared against the previous widget tree and any differences are applied to the underlying render tree, similar ...
An object in the render tree. 顾名思义,RenderObject 主要负责实现视图渲染的对象。渲染时所涉及到的尺寸、布局、约束条件等都是由它来控制的。因此,RenderObject 实例化成本非常昂贵。和 Widget, Element 的一样,Flutter 程序中也有一棵 RenderObject 树。 注:RenderObject 是个总称,不同的 Widget 会有不同类型...
// ./packages/flutter/lib/src/widgets/binding.dartvoidattachRootWidget(WidgetrootWidget){_readyToProduceFrames=true;_renderViewElement=RenderObjectToWidgetAdapter<RenderBox>(container:renderView,debugShortDescription:'[root]',child:rootWidget,).attachToRenderTree(buildOwner,renderViewElementasRenderObjectToWid...
WidgetsFlutterBinding继承了RendererBinding。 接着上边handleDrawFrame的流程: void_handlePersistentFrameCallback(Duration timeStamp) { drawFrame(); _scheduleMouseTrackerUpdate(); } WidgetBinding重载了drawFrame,把build流程加入进来了。 @overridevoiddrawFrame() {try{if(renderViewElement !=null)buildOwner.buil...
voidmain()=>runApp(MyApp());--->[flutter/lib/src/widgets/binding.dart:778]---voidrunApp(Widget app){WidgetsFlutterBinding.ensureInitialized()..attachRootWidget(app)..scheduleWarmUpFrame();}classMyAppextendsStatelessWidget{//略...} 1.2
flutter的入口,就是runApp方法,我们也从这个方法开始查看 代码语言:javascript 复制 voidmain(){runApp(constMyApp());} 进入runApp方法,外部传的widget传给了scheduleAttachRootWidget方法 代码语言:javascript 复制 voidrunApp(Widget app){WidgetsFlutterBinding.ensureInitialized()..scheduleAttachRootWidget(app)..sc...
4.1:布局类组件简介 ·《Flutter实战》 (flutterchina.club) 布局类组件都会包含一个或多个子组件,不同的布局类组件对子组件排版(layout)方式不同。 我们在前面说过Element树才是最终的绘制树,Element树是通过Widget树来创建的(通过Widget.createElement()),Widget其实就是Element的配置数据。
- 'WidgetsBinding' is from 'package:flutter/src/widgets/binding.dart' ('../../../Developer/flutter/packages/flutter/lib/src/widgets/binding.dart'). WidgetsBinding.instance!.addPostFrameCallback((_) { it's bug from flutter? Can anyone report this to flutter. i don't know t...