flex应用看久了，一个默认的装载loading界面就会导致审美疲劳，下面提供一种方法，让你可以自定义你的装载界面。
1，在src目录下建立自定义类，两个文件代码如下：
Preloader.as
package com.preloader{ import mx.preloaders.DownloadProgressBar; import flash.display.Sprite; import flash.events.ProgressEvent; import flash.events.Event; import mx.events.FlexEvent; import mx.managers.SystemManager; import mx.managers.BrowserManager; import flash.utils.Timer; import flash.events.TimerEvent; public class Preloader extends DownloadProgressBar { public var m_Progress: ProgressBar; private var m_Timer: Timer; public function Preloader(): void{ super(); var browser: BrowserManager; m_Progress = new ProgressBar; this.addChild(m_Progress); m_Timer = new Timer(1); m_Timer.addEventListener(TimerEvent.TIMER, timerEventHandler); m_Timer.start(); } override public function set preloader(value:Sprite):void{ value.addEventListener(ProgressEvent.PROGRESS, progressEventHandler); value.addEventListener(Event.COMPLETE, completeEventHandler); value.addEventListener(FlexEvent.INIT_PROGRESS, initProgressEventHandler); value.addEventListener(FlexEvent.INIT_COMPLETE, initCompleteEventHandler); } private function progressEventHandler(event: ProgressEvent): void{ var progress: Number = event.bytesLoaded / event.bytesTotal * 100; if (m_Progress){ m_Progress.progress = progress; } } private function timerEventHandler(event: TimerEvent): void{ this.stage.addChild(this); var width: Number = this.stage.stageWidth * 40 / 100; // Get 40% for the Stage width // Set the Position of the Progress bar to the middle of the screen m_Progress.x = (this.stage.stageWidth - m_Progress.getWidth()) / 2; m_Progress.y = (this.stage.stageHeight - m_Progress.getHeight()) / 2; m_Progress.refreshProgressBar(); } private function completeEventHandler(event: Event): void{ var i: int = 0; } private function initProgressEventHandler(event: FlexEvent): void{ var i: int = 0; } private function initCompleteEventHandler(event: FlexEvent): void{ m_Progress.ready = true; m_Timer.stop(); this.dispatchEvent(new Event(Event.COMPLETE)); } }}
ProgressBar.as
package com.preloader{ import flash.display.Bitmap; import flash.display.BitmapData; import flash.display.Graphics; import flash.display.Loader; import flash.display.Sprite; import flash.events.Event; import flash.geom.Matrix; import flash.text.TextField; import flash.text.TextFormat; import flash.text.TextFieldAutoSize; import flash.utils.ByteArray; import mx.controls.Label; import mx.graphics.codec.PNGEncoder; public class ProgressBar extends Loader { // Logo picture [Embed(source="icon/loader.png")] [Bindable] private var logoClass: Class; private var Logo: Bitmap; private var m_Ready: Boolean; private var m_Progress: Number; private var m_BitmapData: BitmapData; // Constant to change to fit your own layout private static var ProgressWidth: int = 150; // Progress bar width private static var PictureWidth: int = 48; // Logo picture width private static var LeftMargin: int = 1; // Left Margin private static var RightMargin: int = 1; // Right Margin private static var Spacing: int = 10; // Spacing between logo and progress bar private static var TopMargin: int = 1; // Top Margin private static var BottomMargin: int = 1; // Bottom Margin private static var PictureHeight: int = 48; // Logo picture height private static var ProgressHeight: int = 12; // Progress bar height private static var ProgressBarBackground: uint = 0xFFFFFF; private static var progressBarOuterBorder: uint = 0x323232; private static var ProgressBarColor: uint = 0xFF4707; private static var ProgressBarInnerColor: uint = 0xFFFFFF; public function ProgressBar(): void{ super(); m_Progress = 0; Logo = new logoClass as Bitmap; this.addEventListener(Event.RENDER, renderEventHandler); } private function renderEventHandler(event: Event): void{ } public function refreshProgressBar(): void{ m_BitmapData = drawProgress(); // Create the bitmapdata object var encoder: PNGEncoder = new PNGEncoder(); var byteArray: ByteArray = encoder.encode(m_BitmapData); // Encode the bitmapdata to a bytearray this.loadBytes(byteArray); // Draw the bitmap on the loader object } public function getWidth(): Number{ return LeftMargin + PictureWidth + Spacing + ProgressWidth + RightMargin; } public function getHeight(): Number{ return TopMargin + PictureHeight + BottomMargin; } private function drawProgress(): BitmapData{ // Create the bitmap class object var bitmapData: BitmapData = new BitmapData(getWidth(), getHeight(), true, 0); // Draw the Progress Bar var sprite: Sprite = new Sprite(); var graph: Graphics = sprite.graphics; // Draw the progress bar background graph.beginFill(ProgressBarBackground); graph.lineStyle(1, progressBarOuterBorder, 1, true); var containerWidth: Number = ProgressWidth; var px: int = getWidth() - RightMargin - ProgressWidth; var py: int = (getHeight() - ProgressHeight)*2/3; graph.drawRoundRect(px, py, containerWidth, ProgressHeight, 0); containerWidth -= 4; var progressWidth: Number = containerWidth * m_Progress / 100; graph.beginFill(ProgressBarColor); graph.lineStyle(1, ProgressBarInnerColor, 1, true); graph.drawRoundRect(px+1, py+1, progressWidth, ProgressHeight-2, 0); //Construct the Text Field Object and put the progress value in it var textField: TextField = new TextField(); //textField.background = true; //textField.border = true; var format:TextFormat = new TextFormat(); format.font = "Verdana"; format.color = 0x000000; format.size = 10; //format.bold = true; textField.defaultTextFormat = format; textField.text = m_Progress.toFixed(0) + "%"; //Create a BitmapData object and take the Width and height of the TextField text. var textBitmapData: BitmapData = new BitmapData(textField.textWidth + 5, textField.textHeight); //Set the BitmapData object background color to the background color of the progress bar textBitmapData.floodFill(0, 0, ProgressBarBackground); //Draw the TextFiel object in the BitmapData object textBitmapData.draw(textField); //Construct the matrix object //The matrix object is used to place the text var textBitmapMatrix: Matrix = new Matrix(); textBitmapMatrix.translate(px + (containerWidth-textBitmapData.width) / 2, py + (ProgressHeight - textBitmapData.height) / 2-2); var textField1: TextField = new TextField(); var format1:TextFormat = new TextFormat(); format1.color = 0x0b333c; textField1.defaultTextFormat = format1; textField1.text = "系统正在装载，请稍候"; textField1.autoSize = TextFieldAutoSize.LEFT; //Create a BitmapData object and take the Width and height of the TextField text. var textBitmapData1: BitmapData = new BitmapData(textField1.textWidth + 5, textField1.textHeight); //Set the BitmapData object background color to the background color of the progress bar textBitmapData1.floodFill(0, 0, ProgressBarBackground); //Draw the TextFiel object in the BitmapData object textBitmapData1.draw(textField1); //Construct the matrix object //The matrix object is used to place the text var textBitmapMatrix1: Matrix = new Matrix(); textBitmapMatrix1.translate(px, 2); //Draw the sprite object on the parent BitmapData bitmapData.draw(sprite); //Draw the text on the parent BitmapData bitmapData.draw(textBitmapData, textBitmapMatrix, null, null, null, false); bitmapData.draw(textBitmapData1, textBitmapMatrix1, null, null, null, false); //Draw the Logo bitmapData.draw(Logo.bitmapData, null, null, null, null, true); return bitmapData; } public function set ready(value: Boolean): void{ m_Ready = value; this.visible = !value; } public function get ready(): Boolean{ return m_Ready; } public function set progress(value: Number): void{ m_Progress = value; } public function get progress(): Number{ return m_Progress; } }}
2,修改你的Application的属性： preloader="com.preloader.Preloader"
3,运行应用，默认的loading已经变成你想要的效果了。
转自：http://www.cnblogs.com/taobataoma/archive/2008/12/19/1358003.html
转载于:https://www.cnblogs.com/wuhenke/archive/2010/01/09/1642738.html
