Flex 初始化时的事件测试

发布时间：2020-12-15 04:29:52 所属栏目：百科来源：网络整理

导读：flex组件在建立的时候都会经历四个事件：preinitialize,?initialize,?creationComplete和updateComplete（updateComplete事件在任何改动视觉的情况下都会发生，不是初始化时独有的）。我这里有个例子来检测在嵌套和平行的情况下，测试各个组件的事件抛出顺序

flex组件在建立的时候都会经历四个事件：preinitialize,?initialize,?creationComplete和updateComplete（updateComplete事件在任何改动视觉的情况下都会发生，不是初始化时独有的）。我这里有个例子来检测在嵌套和平行的情况下，测试各个组件的事件抛出顺序。

 <?xml?version="1.0"?encoding="utf-8"?>??
 <mx:Application?xmlns:mx="http://www.adobe.com/2006/mxml"?layout="absolute"???
 ????preinitialize="showEvent(event)"???
 ????initialize="showEvent(event)"???
 ????creationComplete="showEvent(event)"???
 ????updateComplete="showEvent(event)">??
 ???
 ????<mx:Script>??
 ????????<!--[CDATA[??
 ????????????import?flash.utils.getTimer;??
 ????????????private?function?showEvent(event:Event):void??
 ????????????{??
 ????????????????trace(flash.utils.getTimer().toString()+"?>>?"??
 ????????????????+event.currentTarget.name+"?"+event.type);??
 ????????????}??
 ????????]]-->??
 ????</mx:Script>??
 ???
 ????<mx:Canvas?id="canv1"??
 ????????preinitialize="showEvent(event)"???
 ????????initialize="showEvent(event)"???
 ????????creationComplete="showEvent(event)"???
 ????????updateComplete="showEvent(event)">??
 ????????<mx:Button?id="btn1"??
 ????????????preinitialize="showEvent(event)"???
 ????????????initialize="showEvent(event)"???
 ????????????creationComplete="showEvent(event)"???
 ????????????updateComplete="showEvent(event)"/>??
 ????</mx:Canvas>??
 ????<mx:Button?id="btn2"??
 ????????????preinitialize="showEvent(event)"???
 ????????????initialize="showEvent(event)"???
 ????????????creationComplete="showEvent(event)"???
 ????????????updateComplete="showEvent(event)"/>??
 </mx:Application>??

输出：

349?>>?InitExample0?preinitialize?? 356?>>?canv1?preinitialize??
 359?>>?btn1?preinitialize??
 369?>>?btn1?initialize??
 370?>>?canv1?initialize??
 371?>>?btn2?preinitialize??
 372?>>?btn2?initialize??
 372?>>?InitExample0?initialize??
 476?>>?btn1?creationComplete??
 477?>>?btn1?updateComplete??
 477?>>?canv1?creationComplete??
 477?>>?canv1?updateComplete??
 477?>>?btn2?creationComplete??
 477?>>?btn2?updateComplete??
 478?>>?InitExample0?creationComplete??
 481?>>?InitExample0?updateComplete??

结论：

就单个组件而言，事件的抛出顺序是preinitialize，initialize，creationComplete

嵌套关系的两个组件（比如Canvas和button1），preinitialize先外后内，initialize和creationComplete先内后外。只是creationComplete要在下一次update才会发生。

平行关系的两个组件（比如Canvas和button2），按mxml内的顺序，只有前面组件initialize结束后，后面的组件才会抛出preinitialize。

（编辑：李大同）

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