1.加载图片

最简单加载

var loader:Loader = new Loader();
var request:URLRequest = new URLRequest("images/flower.jpg");
loader.load(request);
//圆形遮盖
//loader.mask = masker;
addChild(loader);
loader.x = 556;
loader.y = 60;

加上基本加载进度的控制及淡入淡出效果

//淡入淡出特效
/**
greensock库地址：待补充
*/
import com.greensock.*;
import com.greensock.easing.*;
var mc:MovieClip = new MovieClip();
mc.addChild(loader);
addChild(mc);

//分别侦听图片的下载开始、下载中和下载结束事件
loader.contentLoaderInfo.addEventListener(Event.OPEN, openHandler);
loader.contentLoaderInfo.addEventListener(ProgressEvent.PROGRESS, progressHandler);
loader.contentLoaderInfo.addEventListener(Event.INIT, initHandler);
//图片开始下载时，设置mc为完全透明，以便于设置后面的淡入动画效果
function openHandler(event:Event):void {
    mc.alpha = 0;
}
//图片下载时，不断触发progressHandler函数，刷新进度条显示
function progressHandler(event:ProgressEvent):void {
    mProgress.bar.scaleX = event.bytesLoaded/event.bytesTotal;
    mProgress.tLoadingProgress.text = Math.round(event.bytesLoaded/event.bytesTotal*100)+"%";
}
//图片下载并初始化完毕后，进度条淡出，0.5秒后图片淡入
function initHandler(event:Event):void {
    TweenLite.to(mc, 1, {alpha:1,delay:.5});
    TweenLite.to(mProgress, 1, {alpha:0});
}

可以用逐帧方式表达更逼真的缓动效果

//导入TweenLite
import com.greensock.*;
import com.greensock.easing.*;

//将图片加载到loader中，并通过mc显示到舞台
var mc:MovieClip = new MovieClip();
var loader:Loader = new Loader();
loader.load(new URLRequest("images/flower_3.jpg"));
mc.addChild(loader);
addChild(mc);
mc.x = 77;
mc.y = 203;

//分别侦听图片的下载开始、下载中和下载结束事件
loader.contentLoaderInfo.addEventListener(Event.OPEN, openHandler);
loader.contentLoaderInfo.addEventListener(ProgressEvent.PROGRESS, progressHandler);
//图片开始下载时，设置bar元件的enterframe事件侦听
function openHandler(event:Event):void {
    mc.alpha = 0;
    mProgress.bar.scaleX = 0;
    mProgress.bar.tsx = 0;
    mProgress.bar.addEventListener(Event.ENTER_FRAME, refreshBar);
}
//图片下载过程中，bar元件的宽度以平滑方式变化
function refreshBar(event:Event):void{
    //该算法设置了一个弹性值，使bar元件的宽度变化带有缓动值，缓动程度取决于算法的分母
    mProgress.bar.scaleX += ( mProgress.bar.tsx - mProgress.bar.scaleX) / 10;
    //由于以上算法将使bar元件永远无限接近100%宽度，当bar元件的宽度缩放值大于99%时，移除enterframe事件侦听，显示图片
    if(mProgress.bar.scaleX>.99){
        mProgress.bar.removeEventListener(Event.ENTER_FRAME, refreshBar);
        showImage();
    }
}
//图片下载时，不断触发progressHandler函数，刷新bar元件的scaleX目标值
function progressHandler(event:ProgressEvent):void {
    mProgress.bar.tsx = event.bytesLoaded/event.bytesTotal;
}
//显示图片
function showImage():void {
    TweenLite.to(mc, 1, {alpha:1,delay:.5});
    TweenLite.to(mProgress, 1, {alpha:0});
}

一般加载而言，上面代码够用了，如果要自定义加载动画，精确控制加载过程以及异常处理等，参考如下代码：

import com.greensock.*;
import com.greensock.easing.*;

var mc:MovieClip = new MovieClip();
var loader:Loader = new Loader();
var urlrequest:URLRequest = new URLRequest("images/flower_5.jpg");
loader.load(urlrequest);
mc.addChild(loader);
addChild(mc);
mc.x = 67;
mc.y = 91;
mc.alpha = 0;
loader.contentLoaderInfo.addEventListener(Event.OPEN, openHandler);
loader.contentLoaderInfo.addEventListener(ProgressEvent.PROGRESS, progressHandler);
loader.contentLoaderInfo.addEventListener(Event.COMPLETE, completeHandler);
loader.contentLoaderInfo.addEventListener(Event.INIT, initHandler);
loader.contentLoaderInfo.addEventListener(HTTPStatusEvent.HTTP_STATUS, httpstatusHandler);
loader.contentLoaderInfo.addEventListener(IOErrorEvent.IO_ERROR, ioerrorHandler);
loader.contentLoaderInfo.addEventListener(Event.UNLOAD, unloadHandler);
this.addEventListener(Event.ENTER_FRAME, onEnterFrameHandler);
var i:Number = 0;
var loadingProgress:Number = 0;
var frameTotal:Number = 50;
function onEnterFrameHandler(e){
    if(loadingProgress>i){
        i++;
        //mProgress为自定义动画，总共frameTotal帧
        mProgress.gotoAndStop(i);
    }
    if(i==50){
        this.removeEventListener(Event.ENTER_FRAME, onEnterFrameHandler);
        TweenLite.to(mc, 1, {alpha:1,delay:0});
        //TweenLite.to(mProgress, 1, {alpha:0});
    }
}
function openHandler(event:Event):void {
    trace("loading begins");
}
function progressHandler(event:ProgressEvent):void {
    //mProgress.gotoAndStop();
    loadingProgress = Math.round(event.bytesLoaded/event.bytesTotal*frameTotal)
    //tLoadingProgress.text = String(Math.round(event.bytesLoaded/event.bytesTotal*100)+"%");
}
function completeHandler(event:Event):void {
    trace("loading completed");
}
function initHandler(event:Event):void {
    /*TweenLite.to(mc, 1, {alpha:1,delay:.5});
    TweenLite.to(mProgress, 1, {alpha:0});*/
    trace("width: "+event.target.content.width);
}
function httpstatusHandler(event:HTTPStatusEvent):void {
    trace("httpstatus: "+event);
}
function ioerrorHandler(event:IOErrorEvent):void {
    trace("ioerror: "+event);
}
function unloadHandler(event:Event):void {
    trace("unload");
}

2.swf文件自身加载

//首先，让文件在第一帧停止播放
stop();
//初始化txt文本框显示
txt.text = "0%";
//为文件自身注册“下载中”和“下载完毕”事件侦听
this.loaderInfo.addEventListener(Event.COMPLETE, completeHandler);
this.loaderInfo.addEventListener(ProgressEvent.PROGRESS, progressHandler);
//当文件正在下载时，不断触发progressHandler函数来刷新百分比进度显示
function progressHandler(event:ProgressEvent):void {
    txt.text = Math.round(event.bytesLoaded/event.bytesTotal*100)+"%";
}
//当文件下载完毕后，跳转到第二帧显示
function completeHandler(event:Event):void{
    this.gotoAndStop(2);
}

3.多文件加载

建议使用第三方库BulkLoader,好处是方便控制整体进度

import com.greensock.*;
//导入BulkLoader
import br.com.stimuli.loading.BulkLoader;
import br.com.stimuli.loading.BulkProgressEvent;
//创建一个BulkLoader对象
var bulkLoader : BulkLoader = new BulkLoader("myloader");
//向bulkLoader中添加需要加载的图片路径
for (var i:Number=0; i<8; i++) {
    bulkLoader.add("images/0"+i+".jpg", {id:"img"+i});
}
//当所有文件加载完毕时触发onAllItemsLoaded函数
bulkLoader.addEventListener(BulkLoader.COMPLETE, onAllItemsLoaded);
//当下载进行时触发onAllItemsProgress函数
bulkLoader.addEventListener(BulkLoader.PROGRESS, onAllItemsProgress);
//开始加载
bulkLoader.start();
//下载进行时，刷新百分比进度显示
function onAllItemsProgress(e : BulkProgressEvent):void {
    tLoading.text = Math.round(e.percentLoaded*100)+"%";
}
//所有图片加载完毕时，从bulkLoader中取出每张图片并显示到舞台中
function onAllItemsLoaded(e : Event):void {
    tLoading.text = "100%";
    for (var i:Number=0; i<8; i++) {
        var mc:MovieClip = new MovieClip();
        mc.x = 68+(i%4)*221;
        mc.y = 174 + Math.floor(i/4)*136;
        mc.addChild(bulkLoader.getBitmap("img"+i));
        addChild(mc);
    }
}

4.加载swf

import com.greensock.*;
//创建一个子文件的显示容器
var mc:MovieClip = new MovieClip();
var loader:Loader = new Loader();
var urlrequest:URLRequest = new URLRequest("swf/9.swf");
//加载子文件
loader.load(urlrequest);
mc.addChild(loader);
addChild(mc);
//侦听子文件的加载完毕事件
loader.contentLoaderInfo.addEventListener(Event.INIT, initHandler);
//当子文件加载完毕时，从子文件第二帧开始播放动画，并淡出下载中标志
function initHandler(event:Event):void {
    event.target.content.gotoAndPlay(2);
    event.target.content.app = this;
    TweenLite.to(mRing, 1, {alpha:0});
}

4.1.父子swf的交互

加载好swf后，可以控制子swf的内容，这是父控制子；子也可以控制父；原理就是变量赋值，参考代码：

import com.greensock.*;

var mc:MovieClip = new MovieClip();
addChild(mc);

function initHandler(event:Event):void {
    event.target.content.gotoAndPlay(2);
    //设置子文件的父容器引用变量
    event.target.content.app = this;
    TweenLite.to(mRing, 1, {alpha:0});
}
function openSec(target:String) {
    mRing.alpha = 1;
    //清空mc，避免加载的子文件重叠在一起
    if (mc.numChildren>0) {
        var loop:Number = mc.numChildren;
        for (var i:Number = 0; i < loop; i++) {
            mc.removeChildAt(0);
        }
    }
    var loader:Loader = new Loader();
    //根据target参数判断加载哪个子文件
    if (target=="main") {
        loader.load(new URLRequest("swf/9_1.swf"));
    } else if (target=="sub") {
        loader.load(new URLRequest("swf/9_2.swf"));
    }
    mc.addChild(loader);
    loader.contentLoaderInfo.addEventListener(Event.INIT, initHandler);
}
openSec("main");

//swf/9_1.swf的最后一帧上
stop();
bMore.addEventListener(MouseEvent.MOUSE_DOWN, onMouseDownHandeler);
function onMouseDownHandeler(e:MouseEvent):void{
    if(this.app){
        this.app.openSec("sub");
    }
}

//swf/9_2.swf的最后一帧上
stop();
bBack.addEventListener(MouseEvent.MOUSE_DOWN, onMouseDownHandeler);
function onMouseDownHandeler(e:MouseEvent):void{
    if(this.app){
        this.app.openSec("main");
    }
}

5 本地文件加载

//导入FileReference类
import flash.net.FileReference;
//创建一个FileReference对象
var fileReference:FileReference = new FileReference();
//创建一个文件类型过滤对象
var fileFilter:FileFilter = new FileFilter("文本文件","*.txt");
bBrowse.addEventListener(MouseEvent.MOUSE_DOWN, browseFile);
bClear.addEventListener(MouseEvent.MOUSE_DOWN, clearTF);

fileReference.addEventListener(Event.SELECT, onSelectFile);
fileReference.addEventListener(Event.COMPLETE,onFileComplete);
//当按下BROWSE按钮时，弹出文件对话框，供用户选择要打开的文件
function browseFile(e:MouseEvent) {
    //通过使用fileFilter来限制用户只能选择txt文本文件
    fileReference.browse([fileFilter]);
}
//当用户在文件对话框中选择某个文件后，在Flash中加载该文件
function onSelectFile(event:Event):void {
    fileReference.load();
}

//当文件加载完毕时，显示文本内容
function onFileComplete(event:Event):void {
    //在tf文本框中显示打开文件的名称
    tf.htmlText = "opening: " + fileReference.name + "<br>";
    //加载的文本数据为二进制数据，需要将其转换为GB2312编码的字符串
    var bytes:ByteArray = fileReference.data;
    //var newtext:String=fileReference.data.readMultiByte(fileReference.data.length,"gb2312");//默认是UTF-8
    //在tf文本框中显示文本内容
    tf.appendText(newtext);
}

//当按下CLEAR按钮时，清空文本显示
function clearTF(e){
    tf.text = "";   
}

6.本地图像加载

var refF:FileReference = new FileReference();
var fileFilter:FileFilter = new FileFilter("Images","*.png;*.gif;*.jpg");
var loader:Loader = new Loader();

bBrowse.addEventListener(MouseEvent.MOUSE_DOWN, browseImage);
function browseImage(e:MouseEvent):void {
    refF.browse([fileFilter]);
    refF.addEventListener(Event.SELECT,onSelectFile);
}
function onSelectFile(e:Event):void {
    refF.load();
    refF.addEventListener(Event.COMPLETE,onComplete);
    //移除refF的SELECT事件侦听
    refF.removeEventListener(Event.SELECT,onSelectFile);
}
function onComplete(e:Event):void {
    //移除refF的COMPLETE事件侦听
    refF.removeEventListener(Event.COMPLETE,onComplete);
    //使用Loader对象以二进制方式加载位图数据
    loader.loadBytes(refF.data);
    //显示图像
    loader.contentLoaderInfo.addEventListener(Event.COMPLETE,onLoadComplete);
}
//当Loader对象的位图数据加载完毕时，显示图像
function onLoadComplete(e:Event):void {
    var pt:Point = new Point(0, 0);
    //创建一个BitmapDat位图对象，宽度和高度与所加载的位图相同，
    var tempData:BitmapData = new BitmapData(loader.width,loader.height);
    //在BitmapData中绘制位图
    tempData.draw(loader);
    //溶解位图,雪花点效果（可选）
    //tempData.pixelDissolve(tempData, tempData.rect, pt, Math.random(), 20000, 0x99FFFFFF);
    //将BitmapData位图转换为可显示的Bitmap对象
    var bitmap:Bitmap = new Bitmap(tempData);
    //将Bitmap对象显示在mHolder容器中
    mHolder.addChild(bitmap);
}