预览:http://www.onflex.org/flexapps/components/CustomPreloader/
package preload{ import flash.display.Loader; import flash.utils.ByteArray; import flash.events.MouseEvent; import flash.events.TimerEvent; import flash.utils.Timer; public class WelcomeScreen extends Loader//继承其他类吧??? { [ Embed(source="welcome.gif", mimeType="application/octet-stream") ]//要求这个progress bar加载前,先把welcome.gif下载好,以便代码之用 public var WelcomeGif:Class;//建立一个空类 public var timer:Timer;//建立一个定时器 private var fadeInRate:Number = .01;//设定透明度每次增加的量 private var fadeOutRate:Number = .02;//设定透明度每次减少的量 private var timeAutoClose:int = 500; public var ready:Boolean = false; public function WelcomeScreen()//本类的构造函数,在实例化的时候首先执行 { this.visible = false;//不显示 this.alpha = 0;//完全透明 timer = new Timer( 1 );//建立定时器,时间间隔为1毫秒?? timer.addEventListener( TimerEvent.TIMER, updateView );//建立一个显示的过程 timer.start(); this.loadBytes( new WelcomeGif() as ByteArray );//把图片load进实例化为ByteArray的WelcomeGif类里面,详细看loadBytes的用法(这句应该是属于显示图片的关键语句吧) this.addEventListener( MouseEvent.MOUSE_DOWN, mouseDown );//建立鼠标帧听时间(实现点击鼠标就关闭???) } public function updateView( event:TimerEvent ):void//图片从全透明变成不透明的方法 { if( this.alpha < 1) this.alpha = this.alpha + this.fadeInRate; this.stage.addChild(this) this.x = this.stage.stageWidth/2 - this.width/2 this.y = this.stage.stageHeight/2 - this.height/2 this.visible=true; if( this.ready && timer.currentCount > this.timeAutoClose ) closeScreen() //如果ready为true??与定时器的值大于上面设置的500,就关闭图片 } public function closeScreen():void//关闭图片的方法,去掉2个帧听,加入一个新的帧听,让图片渐渐消失 { timer.removeEventListener( TimerEvent.TIMER, updateView ); timer.removeEventListener( MouseEvent.MOUSE_DOWN, mouseDown); timer.addEventListener( TimerEvent.TIMER, closeScreenFade ); } public function closeScreenFade( event:TimerEvent ):void//图片渐渐消失的过程,透明度不断变小,当透明度不大于0(就是为0时),timer停止,图片被去掉 { if( this.alpha > 0){ this.alpha = this.alpha - fadeOutRate; } else { timer.stop() this.parent.removeChild(this); } } public function mouseDown( event:MouseEvent ):void//这里简单,老鼠一点,就关闭了 { closeScreen(); } }}
转自:http://gdlszxx.gjjblog.com/archives/892823/
相关资源:敏捷开发V1.0.pptx