我正在努力使这段代码变得可恢复，并再次下载一个URL数组，但我正在努力。代码似乎只下载了最后一个文件但忽略了第一个文件。
<?xml version="1.0" encoding="utf-8"?>
<mx:WindowedApplication xmlns:mx="http://www.adobe.com/2006/mxml" applicationComplete="init(event)" viewSourceURL="srcview/index.html">
<mx:Script>
<![CDATA[
import flash.events.Event;
import flash.events.ProgressEvent;
import flash.net.URLRequest;
import flash.net.URLStream;
import flash.utils.ByteArray;
import mx.controls.Alert;
import mx.events.FlexEvent;
//Declear variables
private var urlStream:URLStream;
private var fData:ByteArray;
private var bytesLoaded:Number = 0;
private var totalBytesLoaded:Number = 0;
private var bytesTotal:Number = 0;
private var fileName:String = "";
private var file:File;
private var fileStream:FileStream = new FileStream;
//initialize even listeners
protected function init(event:FlexEvent):void{
urlStream = new URLStream;
urlStream.addEventListener(ProgressEvent.PROGRESS, onProgress);
urlStream.addEventListener(Event.COMPLETE, onComplete);
var letters:Array = ["http://www.khanhvanweb.com/Music/Spanish Guitar Toni Braxton.mp3","http://dropthebeat.tv/audio/ToniBraxton-Please.mp3"];
for (var i:int = 0; i < letters.length; i++) {
trace("Element " + i + ": " + letters[i]);
fileInput.text = letters[i];
startDownload();
}
}
//Start Downloaing
// if (fileInput.text = ""){
public function startDownload():void{
bytesLoaded = 0;
bytesTotal = 0;
totalBytesLoaded = 0;
var url:String = fileInput.text;
var index:int = url.lastIndexOf('/');
fileName = url.substring(index+1, url.length);
var str1:String = "/Music/ClassicalShop.Net/";
// file = File.documentsDirectory.resolvePath(fileName);
//'Save to classical muic directory
file = File.userDirectory.resolvePath(String(File.userDirectory.url + str1 + fileName));
status = file.url;
if(file.exists) {
btn.label = 'Download';
mx.controls.Alert.show('Please remove "'+fileName+'" from your disk', 'File with the same name already exists');
return;
}
output.text += 'Downloading\n';
urlStream.load( new URLRequest(url) );
fData = new ByteArray;
fileInput.enabled = false;
fileStream.open(file, file.exists ? FileMode.APPEND:FileMode.WRITE); }
// }
private function pauseDownload():void {
output.text += 'Downloading is paused\n';
if(urlStream.connected) {
fData.clear();
urlStream.readBytes(fData, fData.length);
urlStream.close();
fileStream.writeBytes(fData);
}
fileStream.close();
totalBytesLoaded += bytesLoaded;
trace( "pause size:"+ totalBytesLoaded);
}
//Resume the Download
private function resumeDownload():void {
output.text += 'Downloading \n';
output.text +='bytes='+totalBytesLoaded+'-'+bytesTotal + '\n';
var header0:URLRequestHeader = new URLRequestHeader('range', 'bytes='+totalBytesLoaded+'-'+bytesTotal);
var request:URLRequest = new URLRequest(fileInput.text);
request.requestHeaders.push(header0);
urlStream.load( request );
fileStream.open(file, file.exists ? FileMode.APPEND:FileMode.WRITE);
}
//Set progress of the file download
private function onProgress(event:ProgressEvent):void {
bytesLoaded = event.bytesLoaded;
if(bytesTotal == 0)
bytesTotal = event.bytesTotal;
trace( "size:"+ bytesLoaded);
progressBar.setProgress( (totalBytesLoaded + event.bytesLoaded) / bytesTotal, progressBar.maximum);
if(urlStream.bytesAvailable == 0) return;
if(urlStream.connected)
{
fData.clear();
urlStream.readBytes(fData, fData.length);
fileStream.writeBytes(fData);
}
}
//Action to take when the file has completed downloading
private function onComplete(event:Event):void
{
output.text += 'Download complete\n';
bytesLoaded = 0;
bytesTotal = 0;
totalBytesLoaded = 0;
progressBar.setProgress(0, 1);
if(urlStream.connected)
{
fData.clear();
urlStream.readBytes(fData, fData.length);
urlStream.close();
fileStream.writeBytes(fData);
}
fileInput.enabled = true;
btn.label = 'Download';
fData = null;
fileStream.close();
System.gc();
}
//write the file to disk
private function writeFile():void
{
output.text += 'Saving File\n';
var fileStream:FileStream = new FileStream;
fileStream.open(file, file.exists ? FileMode.APPEND:FileMode.WRITE);
fileStream.writeBytes(fData);
fileStream.close();
output.text += 'File Saved\n';
}
private function btnClickHandler():void
{
if(bytesLoaded == 0)
{
btn.label = 'Pause';
startDownload();
}
else
{
if(urlStream.connected)
{
btn.label = 'Resume';
pauseDownload();
}
else
{
btn.label = 'Pause';
resumeDownload();
}}}
]]>
</mx:Script>
<mx:TextInput id="fileInput" y="15" left="67" right="10"/>
<mx:Button id="btn" x="286" y="65" label="Download" click="btnClickHandler()"/>
<mx:ProgressBar id="progressBar" x="67" y="65"
mode="manual" minimum="0" maximum="1" label="Downloading %3%%"/>
<mx:Label x="10" y="20" text="File URL"/>
<mx:TextArea id="output" left="10" right="10" top="107" bottom="10"/>
<mx:Button y="65" label="Clear Input" right="10"
enabled="{fileInput.text.length==0 ? false:fileInput.enabled}"
click="fileInput.text = ''"/>
<mx:Label x="67" y="46"
text="http://www.example.com/downloads/episode77.mp3"
color="#878787"/>
</mx:WindowedApplication>
答案 0 :(得分：0)
这是因为您正在使用全局变量。当您启动新的URLLoader / URLStream时，它会关闭之前的所有请求并从新请求开始。解决方案很简单。
public function startDownload( urlRequest:URLRequest ):void{
var loader:URLLoader = new URLLoader();
loader.load( urlRequest );
}
显然这只是基础知识，你需要添加其余的代码，但是你明白了。对于每个单独的文件，您需要一个完全独立的URLRequest和URLLoader / URLStream，因此您必须在函数范围内创建它们，而不是全局范围。
如果您需要在COMPLETE或PROGRESS事件中获取URLLoader，请查看event.currentTarget和event.Target。
如果您不希望它们同时运行，您可以在COMPLETE处理程序中手动增加一个“count”变量，并使用该count属性来获取数组中的下一个项目。
答案 1 :(得分：0)
我不确定您是否尝试使用移动平台，但我们刚刚在Android上发布了我们的新的原生扩展，这是一个可恢复的多部分下载管理器。在这里查看：http://myappsnippet.com/download-manager-air-native-extension/