【图】Flash AS3教程：组件的组合运用制作FLV播放器

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　　本例为Flash AS3实例教程，主要学习组件的组合运用制作FLV播放器，通过本教程将实现以下功能，按前进、后退按钮可选择播放，拖动滑块可调节音量，希望能给朋友们带来帮助~~

更多AS 3.0教程：http://www.jcwcn.com/portal-topic-topicid-2.html

组件的组合运用(FLV播放器)

Flash AS3教程：组件的组合运用制作FLV播放器_中国

声明：本实例为Adobe的实例，非本人原创。

实现的功能：按前进、后退按钮可选择播放，拖动滑块可调节音量。

测试环境：Flash CS4

１、组织界面：
新建Flash文档文件，命名保存。
打开组件面板，点开User Interface组。把Label拖到场景中，命名为：postionLabel，拖ProgressBar到场景中，命名为：positionBar，拖Slider到场景中，命名为：volumeSlider，点开Video组。拖PlayButton到场景中，命名为：playButton，拖PauseButton到场景中，命名为：pauseButton，拖StopButton到场景中，命名为：stopButton，拖BackButton到场景中，命名为：backButton，拖ForwardButton到场景中，命名为：forwardButton。组织好位置如图1图2：

Flash AS3教程：组件的组合运用制作FLV播放器_中国

２、创建VideoJukebox.as文档文件，代码如下：(代码可直接拷贝)

package {
import fl.controls.*;
import fl.events.SliderEvent;

import flash.display.MovieClip;
import flash.display.Sprite;
import flash.events.Event;
import flash.events.MouseEvent;
import flash.events.NetStatusEvent;
import flash.events.TimerEvent;
import flash.media.SoundTransform;
import flash.media.Video;
import flash.net.NetConnection;
import flash.net.NetStream;
import flash.net.URLLoader;
import flash.net.URLRequest;
import flash.utils.Timer;

public class VideoJukebox extends Sprite {
/**
   * The amount of time between calls to update the playhead timer, in
   * milliseconds.
   */
private const PLAYHEAD_UPDATE_INTERVAL_MS:uint = 10;

/**
   * The path to the XML file containing the video playlist.
   */
private const PLAYLIST_XML_URL:String = "playlist.xml";

/**
   * The client object to use for the NetStream object.
   */
private var client:Object;

/**
   * The index of the currently playing video.
   */
private var idx:uint = 0;

/**
   * A copy of the current video's metadata object.
   */
private var meta:Object;
private var nc:NetConnection;
private var ns:NetStream;
private var playlist:XML;
private var t:Timer;
private var uldr:URLLoader;
private var vid:Video;
private var videosXML:XMLList;

/**
   * The SoundTransform object used to set the volume for the NetStream.
   */
private var volumeTransform:SoundTransform;

/**
   * Constructor
   */
public function VideoJukebox() {
// Initialize the uldr variable which will be used to load the external
// playlist XML file.
uldr = new URLLoader();
uldr.addEventListener(Event.COMPLETE, xmlCompleteHandler);
uldr.load(new URLRequest(PLAYLIST_XML_URL));
}

/**
   * Once the XML file has loaded, parse the file contents into an XML object,
   * and create an XMList for the video nodes in the XML.
   */
private function xmlCompleteHandler(event:Event):void {
playlist = XML(event.target.data);
videosXML = playlist.video;
main();
}

/**
   * The main application.
   */
private function main():void {
volumeTransform = new SoundTransform();

// Create the client object for the NetStream, and set up a callback
// handler for the onMetaData event.
client = new Object();
client.onMetaData = metadataHandler;

nc = new NetConnection();
nc.connect(null);

// Initialize the NetSteam object, add a listener for the netStatus
// event, and set the client for the NetStream.
ns = new NetStream(nc);
ns.addEventListener(NetStatusEvent.NET_STATUS, netStatusHandler);
ns.client = client;

// Initialize the Video object, attach the NetStram, and add the Video
// object to the display list.
vid = new Video();
         vid.x = 20;
         vid.y = 75;
vid.attachNetStream(ns);
addChild(vid);

// Begin playback of the first video.
playVideo();

// Initialize the Timer object and set the delay to
// PLAYHEAD_UPDATE_INTERVAL_MS milliseconds.
t = new Timer(PLAYHEAD_UPDATE_INTERVAL_MS);
t.addEventListener(TimerEvent.TIMER, timerHandler);

// Configure the positionBar ProgressBar instance and set the mode to
// MANUAL. Progress  bar values will be explicitly set using the
// setProgress() method.
positionBar.mode = ProgressBarMode.MANUAL;

// Configure the volumeSlider Slider component instance. The maximum
// value is set to 1 because the volume in the SoundTransform object
// is set to a number between 0 and 1. The snapInterval and tickInterval
// properties are set to 0.1 which allows users to set the volume to
// 0, 0.1 - 0.9, 1.0 which allows users to increment or decrement the
// volume by 10%.
volumeSlider.value = volumeTransform.volume;
volumeSlider.minimum = 0;
volumeSlider.maximum = 1;
volumeSlider.snapInterval = 0.1;
volumeSlider.tickInterval = volumeSlider.snapInterval;

// Setting the liveDragging property to true causes the Slider
// instance's change event to be dispatched whenever the slider is
// moved, rather than when the user releases the slider thumb.
volumeSlider.liveDragging = true;
volumeSlider.addEventListener(SliderEvent.CHANGE, volumeChangeHandler);

// Configure the various Button instances. Each Button instance uses
// the same click handler.
playButton.addEventListener(MouseEvent.CLICK, buttonClickHandler);
pauseButton.addEventListener(MouseEvent.CLICK, buttonClickHandler);
stopButton.addEventListener(MouseEvent.CLICK, buttonClickHandler);
backButton.addEventListener(MouseEvent.CLICK, buttonClickHandler);
forwardButton.addEventListener(MouseEvent.CLICK, buttonClickHandler);
}

/**
   * Event listener for the volumeSlider instance. Called when the user
   * changes the value of the volume slider.
   */
private function volumeChangeHandler(event:SliderEvent):void {
// Set the volumeTransform's volume property to the current value of the
// Slider and set the NetStream object's soundTransform property.
volumeTransform.volume = event.value;
ns.soundTransform = volumeTransform;
}

/**
   * Event listener for the ns object. Called when the net stream's status
   * changes.
   */
private function netStatusHandler(event:NetStatusEvent):void {
try {
switch (event.info.code) {
case "NetStream.Play.Start" :
// If the current code is Start, start the timer object.
t.start();
break;
case "NetStream.Play.StreamNotFound" :
case "NetStream.Play.Stop" :
// If the current code is Stop or StreamNotFound, stop
// the timer object and play the next video in the playlist.
t.stop();
playNextVideo();
break;
}
} catch (error:TypeError) {
// Ignore any errors.
}
}

/**
   * Event listener for the ns object's client property. This method is called
   * when the net stream object receives metadata information for a video.
   */
private function metadataHandler(metadataObj:Object):void {
// Store the metadata information in the meta object.
meta = metadataObj;
// Resize the Video instance on the display list with the video's width
// and height from the metadata object.
vid.width = meta.width;
vid.height = meta.height;
// Reposition and resize the positionBar progress bar based on the
// current video's dimensions.
positionBar.move(vid.x, vid.y + vid.height);
positionBar.width = vid.width;
}

/**
   * Retrieve the current video from the playlist XML object.
   */
private function getVideo():String {
return videosXML[idx].@url;
}

/**
   * Play the currently selected video.
   */
private function playVideo():void {
var url:String = getVideo();
ns.play(url);
}

/**
   * Decrease the current video index and begin playback of the video.
   */
private function playPreviousVideo():void {
if (idx 0) {
idx--;
playVideo();
// Make sure the positionBar progress bar is visible.
positionBar.visible = true;
}
}

/**
   * Increase the current video index and begin playback of the video.
   */
private function playNextVideo():void {
if (idx < (videosXML.length() - 1)) {
// If this is not the last video in the playlist increase the
// video index and play the next video.
idx++;
playVideo();
// Make sure the positionBar progress bar is visible.
positionBar.visible = true;
} else {
// If this is the last video in the playlist increase the video
// index, clear the contents of the Video object and hide the
// positionBar progress bar. The video index is increased so that
// when the video ends, clicking the backButton will play the
// correct video.
idx++;
vid.clear();
positionBar.visible = false;
}
}

/**
   * Click handler for each of the video playback buttons.
   */
private function buttonClickHandler(event:MouseEvent):void {
// Use a switch statement to determine which button was clicked.
switch (event.currentTarget) {
case playButton :
// If the play button was clicked, resume the video playback.
// If the video was already playing, this has no effect.
ns.resume();
break;
case pauseButton :
// If the pause button was clicked, pause the video playback.
// If the video was already playing, the video will be paused.
// If the video was already paused, the video will be resumed.
ns.togglePause();
break;
case stopButton :
// If the stop button was clicked, pause the video playback
// and reset the playhead back to the beginning of the video.
ns.pause();
ns.seek(0);
break;
case backButton :
// If the back button was clicked, play the previous video in
// the playlist.
playPreviousVideo();
break;
case forwardButton :
// If the forward button was clicked, play the next video in
// the playlist.
playNextVideo();
break;
}
}

/**
   * Event handler for the timer object. This method is called every
   * PLAYHEAD_UPDATE_INTERVAL_MS milliseconds as long as the timer is running.
   */
private function timerHandler(event:TimerEvent):void {
try {
// Update the progress bar and label based on the amount of video
// that has played back.
positionBar.setProgress(ns.time, meta.duration);
positionLabel.text = ns.time.toFixed(1) + " of " + meta.duration.toFixed(1) + " seconds";
} catch (error:Error) {
// Ignore this error.
}
}
}
}

３、建一个xml文件，打开记事本输入下面内容：(此文件包涵3段flv地址，需要的话按下面格式添加)

<?xml version="1.0"?
<videos
<video url="http://www.helpexamples.com/flash/video/typing_short.flv" /
<video url="http://www.helpexamples.com/flash/video/cuepoints.flv" /
<video url="http://www.helpexamples.com/flash/video/sheep.flv" /
</videos

在记事本中，选择【文件】【另存为】命令，输入文件名为：playlist.xml，在编码选项中选择UTF-8，单击【保存】按钮。如图3:

Flash AS3教程：组件的组合运用制作FLV播放器_中国