Android提高第二十篇之MediaPlayer播放网络音频

 

本文来自http://blog.csdn.net/hellogv/ ，引用必须注明出处！

     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() {@Overridepublic 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 blocke.printStackTrace();} catch (IllegalStateException e) {// TODO Auto-generated catch blocke.printStackTrace();} catch (IOException e) {// TODO Auto-generated catch blocke.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");}@Overridepublic void onCompletion(MediaPlayer arg0) {Log.e("mediaPlayer", "onCompletion");}@Overridepublic 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);
        }
    }

}