incomingWidgets 为空:为父类Element的 _inheritedWidgets 变量, 实例了一个map对象 incomingWidgets 不为空:将父节点_inheritedWidgets 所有数据深拷贝,返回一个全新的Map实例(含有父节点 _inheritedWidgets 所有数据),赋值给父类Element的 _inheritedWidgets 变量 将自身实例赋值给父类Element的 _inheritedWidgets 变量,...
}/// 页面过渡按钮class_PagePushButtonextendsStatelessWidget{ const _PagePushButton({Key? key, requiredthis.buttonTitle, requiredthis.pagename, }) :super(key: key);finalStringbuttonTitle;finaldynamic pagename;@overrideWidgetbuild(BuildContextcontext) {returnElevatedButton( child:Container( padding: cons...
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当前组件的中保存这样一个 Map 集合,获取共享数据时直接定位依赖的 InheritedWidget,复杂度 O(1) 。 而依次向上查找的复杂度是 O(n),树的结构越深,消耗时间越长,复杂度线性增长。 交流 老孟Flutter博客(330个控件用法+实战入门系列文章):http://laomengit.com ...
Flutter proposed in Roadmap in 2022 that it needs to rethink the way shaders are used, and plans to rewrite the image rendering backend. Recently, the rendering backend Impeller (impeller) has begun to take shape. This article will introduce the problems, goals, architecture and rendering detai...
作者:半步沧桑,Flutter 状态管理 -Provider 的使用和源码解析:前言在各种前端开发中,由于状态管理对于App的开发维护成本,性能等方面都起着至关重要的作用,所以选择合适的状态管理框架显得尤为重要。Flutter作为跨平台框架的后起之秀,背靠Google大树,短时间
存入到了_dependents 这个 HashMap 中；当状态更新的时候，InheritedElement 直接使用旧的组件配置通知子...
Key? key, Create<T>? create, T Function(BuildContext context, T? value)? update, UpdateShouldNotify<T>? updateShouldNotify, void Function(T value)? debugCheckInvalidValueType, StartListening<T>? startListening, Dispose<T>? dispose, this.builder, ...
setupApplicationPackages();finalStringcommandPath =awaitusagePath;if(commandPath !=null) {finalMap<String,String> additionalUsageValues =awaitusageValues; flutterUsage.sendCommand(commandPath, parameters: additionalUsageValues); }returnawaitrunCommand(); ...
if (ancestor != null) { return dependOnInheritedElement(ancestor, aspect: aspect) as T; } _hadUnsatisfiedDependencies = true; return null; } 真正的实现是在Element中进行的。其中_inheritedWidgets是个Map,key为T的类型。从上面代码我们可以知道,先从_inheritedWidgets里寻找类型为T的InheritedElement,即父...