Android提高篇之MediaPlayer播放网络音频

转自：http://blog.csdn.net/hellogv/article/details/6406732

以前曾经地介绍过MediaPlayer的基本用法，这里就深入地讲解MediaPlayer的在线播放功能。本文主要实现MediaPlayer在线播放音频的功能，由于在线视频播放比在线音频播放复杂，因此先介绍在线音频播放的实现，这样可以帮助大家逐步深入了解MediaPlayer的在线播放功能。先来看看本文程序运行的结果：

main.xml的源码如下：

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_height="fill_parent" android:layout_width="fill_parent">
    <LinearLayout android:layout_height="wrap_content"
        android:layout_width="fill_parent" android:orientation="vertical"
        android:layout_gravity="top">
        <LinearLayout android:orientation="horizontal"
            android:layout_gravity="center_horizontal" android:layout_marginTop="4.0dip"
            android:layout_height="wrap_content" android:layout_width="wrap_content">
            <Button android:layout_width="wrap_content"
                android:layout_height="wrap_content" android:id="@+id/btnPlayUrl"
                android:text="播放网络音频"></Button>
            <Button android:layout_height="wrap_content" android:id="@+id/btnPause"
                android:text="暂停" android:layout_width="80dip"></Button>
            <Button android:layout_height="wrap_content"
                android:layout_width="80dip" android:text="停止" android:id="@+id/btnStop"></Button>
        </LinearLayout>
        <LinearLayout android:orientation="horizontal"
            android:layout_width="fill_parent" android:layout_height="wrap_content"
            android:layout_marginBottom="20dip">
            <SeekBar android:paddingRight="10dip" android:layout_gravity="center_vertical"
                android:paddingLeft="10dip" android:layout_weight="1.0"
                android:layout_height="wrap_content" android:layout_width="wrap_content"
                android:id="@+id/skbProgress" android:max="100"></SeekBar>
        </LinearLayout>
    </LinearLayout>
</FrameLayout>

<?xml version="1.0" encoding="utf-8"?> <FrameLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_height="fill_parent" android:layout_width="fill_parent"> <LinearLayout android:layout_height="wrap_content" android:layout_width="fill_parent" android:orientation="vertical" android:layout_gravity="top"> <LinearLayout android:orientation="horizontal" android:layout_gravity="center_horizontal" android:layout_marginTop="4.0dip" android:layout_height="wrap_content" android:layout_width="wrap_content"> <Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@+id/btnPlayUrl" android:text="播放网络音频"></Button> <Button android:layout_height="wrap_content" android:id="@+id/btnPause" android:text="暂停" android:layout_width="80dip"></Button> <Button android:layout_height="wrap_content" android:layout_width="80dip" android:text="停止" android:id="@+id/btnStop"></Button> </LinearLayout> <LinearLayout android:orientation="horizontal" android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_marginBottom="20dip"> <SeekBar android:paddingRight="10dip" android:layout_gravity="center_vertical" android:paddingLeft="10dip" android:layout_weight="1.0" android:layout_height="wrap_content" android:layout_width="wrap_content" android:id="@+id/skbProgress" android:max="100"></SeekBar> </LinearLayout> </LinearLayout> </FrameLayout>

Player.java是本文的核心，Player.java实现了“进度条更新”、“数据缓冲”等功能，虽然不是很复杂的功能，但却是非常有用的功能。Player.java源码如下：

package com.musicplayer;


import java.io.IOException;
import java.util.Timer;
import java.util.TimerTask;
import android.media.AudioManager;
import android.media.MediaPlayer;
import android.media.MediaPlayer.OnBufferingUpdateListener;
import android.media.MediaPlayer.OnCompletionListener;
import android.os.Handler;
import android.os.Message;
import android.util.Log;
import android.widget.SeekBar;

public class Player implements OnBufferingUpdateListener,
        OnCompletionListener, MediaPlayer.OnPreparedListener{
    public MediaPlayer mediaPlayer;
    private SeekBar skbProgress;
    private Timer mTimer=new Timer();
    public Player(SeekBar skbProgress)
    {
        this.skbProgress=skbProgress;

        try {
            mediaPlayer = new MediaPlayer();
            mediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
            mediaPlayer.setOnBufferingUpdateListener(this);
            mediaPlayer.setOnPreparedListener(this);
        } catch (Exception e) {
            Log.e("mediaPlayer", "error", e);
        }

        mTimer.schedule(mTimerTask, 0, 1000);
    }

    /*******************************************************
     * 通过定时器和Handler来更新进度条
     ******************************************************/
    TimerTask mTimerTask = new TimerTask() {
        @Override
        public void run() {
            if(mediaPlayer==null)
                return;
            if (mediaPlayer.isPlaying() && skbProgress.isPressed() == false) {
                handleProgress.sendEmptyMessage(0);
            }
        }
    };

    Handler handleProgress = new Handler() {
        public void handleMessage(Message msg) {

            int position = mediaPlayer.getCurrentPosition();
            int duration = mediaPlayer.getDuration();

            if (duration > 0) {
                long pos = skbProgress.getMax() * position / duration;
                skbProgress.setProgress((int) pos);
            }
        };
    };
    //*****************************************************

    public void play()
    {
        mediaPlayer.start();
    }

    public void playUrl(String videoUrl)
    {
        try {
            mediaPlayer.reset();
            mediaPlayer.setDataSource(videoUrl);
            mediaPlayer.prepare();//prepare之后自动播放
            //mediaPlayer.start();
        } catch (IllegalArgumentException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IllegalStateException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }


    public void pause()
    {
        mediaPlayer.pause();
    }

    public void stop()
    {
        if (mediaPlayer != null) {
            mediaPlayer.stop();
            mediaPlayer.release();
            mediaPlayer = null;
        }
    }

    @Override
    /**
     * 通过onPrepared播放
     */
    public void onPrepared(MediaPlayer arg0) {
        arg0.start();
        Log.e("mediaPlayer", "onPrepared");
    }

    @Override
    public void onCompletion(MediaPlayer arg0) {
        Log.e("mediaPlayer", "onCompletion");
    }

    @Override
    public void onBufferingUpdate(MediaPlayer arg0, int bufferingProgress) {
        skbProgress.setSecondaryProgress(bufferingProgress);
        int currentProgress=skbProgress.getMax()*mediaPlayer.getCurrentPosition()/mediaPlayer.getDuration();
        Log.e(currentProgress+"% play", bufferingProgress + "% buffer");
    }

}

package com.musicplayer; import java.io.IOException; import java.util.Timer; import java.util.TimerTask; import android.media.AudioManager; import android.media.MediaPlayer; import android.media.MediaPlayer.OnBufferingUpdateListener; import android.media.MediaPlayer.OnCompletionListener; import android.os.Handler; import android.os.Message; import android.util.Log; import android.widget.SeekBar; public class Player implements OnBufferingUpdateListener, OnCompletionListener, MediaPlayer.OnPreparedListener{ public MediaPlayer mediaPlayer; private SeekBar skbProgress; private Timer mTimer=new Timer(); public Player(SeekBar skbProgress) { this.skbProgress=skbProgress; try { mediaPlayer = new MediaPlayer(); mediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC); mediaPlayer.setOnBufferingUpdateListener(this); mediaPlayer.setOnPreparedListener(this); } catch (Exception e) { Log.e("mediaPlayer", "error", e); } mTimer.schedule(mTimerTask, 0, 1000); } /******************************************************* * 通过定时器和Handler来更新进度条 ******************************************************/ TimerTask mTimerTask = new TimerTask() { @Override public void run() { if(mediaPlayer==null) return; if (mediaPlayer.isPlaying() && skbProgress.isPressed() == false) { handleProgress.sendEmptyMessage(0); } } }; Handler handleProgress = new Handler() { public void handleMessage(Message msg) { int position = mediaPlayer.getCurrentPosition(); int duration = mediaPlayer.getDuration(); if (duration > 0) { long pos = skbProgress.getMax() * position / duration; skbProgress.setProgress((int) pos); } }; }; //***************************************************** public void play() { mediaPlayer.start(); } public void playUrl(String videoUrl) { try { mediaPlayer.reset(); mediaPlayer.setDataSource(videoUrl); mediaPlayer.prepare();//prepare之后自动播放 //mediaPlayer.start(); } catch (IllegalArgumentException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (IllegalStateException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } public void pause() { mediaPlayer.pause(); } public void stop() { if (mediaPlayer != null) { mediaPlayer.stop(); mediaPlayer.release(); mediaPlayer = null; } } @Override /** * 通过onPrepared播放 */ public void onPrepared(MediaPlayer arg0) { arg0.start(); Log.e("mediaPlayer", "onPrepared"); } @Override public void onCompletion(MediaPlayer arg0) { Log.e("mediaPlayer", "onCompletion"); } @Override public void onBufferingUpdate(MediaPlayer arg0, int bufferingProgress) { skbProgress.setSecondaryProgress(bufferingProgress); int currentProgress=skbProgress.getMax()*mediaPlayer.getCurrentPosition()/mediaPlayer.getDuration(); Log.e(currentProgress+"% play", bufferingProgress + "% buffer"); } }

test_musicplayer.java是主程序，负责调用Player类，其中关键部分是SeekBarChangeEvent这个SeekBar拖动的事件：SeekBar的Progress是0~SeekBar.getMax()之内的数，而MediaPlayer.seekTo()的参数是0~MediaPlayer.getDuration()之内数，所以MediaPlayer.seekTo()的参数是(progress/seekBar.getMax())*player.mediaPlayer.getDuration()。

test_musicplayer.java源码如下：

package com.musicplayer;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.SeekBar;

public class test_musicplayer extends Activity {
    private Button btnPause, btnPlayUrl, btnStop;
    private SeekBar skbProgress;
    private Player player;

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        this.setTitle("在线音乐播放---hellogv编写");

        btnPlayUrl = (Button) this.findViewById(R.id.btnPlayUrl);
        btnPlayUrl.setOnClickListener(new ClickEvent());

        btnPause = (Button) this.findViewById(R.id.btnPause);
        btnPause.setOnClickListener(new ClickEvent());

        btnStop = (Button) this.findViewById(R.id.btnStop);
        btnStop.setOnClickListener(new ClickEvent());

        skbProgress = (SeekBar) this.findViewById(R.id.skbProgress);
        skbProgress.setOnSeekBarChangeListener(new SeekBarChangeEvent());
        player = new Player(skbProgress);

    }

    class ClickEvent implements OnClickListener {

        @Override
        public void onClick(View arg0) {
            if (arg0 == btnPause) {
                player.pause();
            } else if (arg0 == btnPlayUrl) {
                //在百度MP3里随便搜索到的,大家可以试试别的链接
                String url="http://219.138.125.22/myweb/mp3/CMP3/JH19.MP3";
                player.playUrl(url);
            } else if (arg0 == btnStop) {
                player.stop();
            }
        }
    }

    class SeekBarChangeEvent implements SeekBar.OnSeekBarChangeListener {
        int progress;

        @Override
        public void onProgressChanged(SeekBar seekBar, int progress,
                boolean fromUser) {
            // 原本是(progress/seekBar.getMax())*player.mediaPlayer.getDuration()
            this.progress = progress * player.mediaPlayer.getDuration()
                    / seekBar.getMax();
        }

        @Override
        public void onStartTrackingTouch(SeekBar seekBar) {

        }

        @Override
        public void onStopTrackingTouch(SeekBar seekBar) {
            // seekTo()的参数是相对与影片时间的数字，而不是与seekBar.getMax()相对的数字
            player.mediaPlayer.seekTo(progress);
        }
    }

}