Android提高21篇之一：MediaPlayer

       本文介绍MediaPlayer的使用。MediaPlayer可以播放音频和视频，另外也可以通过VideoView来播放视频，虽然VideoView比MediaPlayer简单易用，但定制性不如用MediaPlayer，要视情况选择了。MediaPlayer播放音频比较简单，但是要播放视频就需要SurfaceView。SurfaceView比普通的自定义View更有绘图上的优势，它支持完全的OpenGL ES库。

       先贴出本文程序运行结果的截图，上面是播放/停止音频，可用SeekBar来调进度，下面是播放/停止视频，也是用SeekBar来调进度：

 

       main.xml的源码：

XML/HTML代码

<linearlayout android:id="@+id/LinearLayout01"
        android:layout_width="fill_parent" android:layout_height="fill_parent"
        xmlns:android="http://schemas.android.com/apk/res/android"
        android:orientation="vertical">
        <seekbar android:id="@+id/SeekBar01" android:layout_height="wrap_content"
                android:layout_width="fill_parent">
        <linearlayout android:id="@+id/LinearLayout02"
                android:layout_width="wrap_content" android:layout_height="wrap_content">
                <button android:id="@+id/Button01" android:layout_width="wrap_content"
                        android:layout_height="wrap_content" android:text="播放音频">
                <button android:id="@+id/Button02" android:layout_width="wrap_content"
                        android:layout_height="wrap_content" android:text="停止播放">

        <seekbar android:id="@+id/SeekBar02" android:layout_height="wrap_content"
                android:layout_width="fill_parent">

        <surfaceview android:id="@+id/SurfaceView01"
                android:layout_width="fill_parent" android:layout_height="250px">
        <linearlayout android:id="@+id/LinearLayout02"
                android:layout_width="wrap_content" android:layout_height="wrap_content">
                <button android:layout_width="wrap_content"
                        android:layout_height="wrap_content" android:id="@+id/Button03"
                        android:text="播放视频">
                <button android:layout_width="wrap_content"
                        android:layout_height="wrap_content" android:text="停止播放" android:id="@+id/Button04">

       本文程序的源码，有点长：

Java代码

package com.testMedia;

import java.io.IOException;
import java.util.Timer;
import java.util.TimerTask;
import android.app.Activity;
import android.media.AudioManager;
import android.media.MediaPlayer;
import android.os.Bundle;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;
import android.widget.Button;
import android.widget.SeekBar;
import android.widget.Toast;


public class testMedia extends Activity {
          /** Called when the activity is first created. */

        private SeekBar skb_audio=null;
    private Button btn_start_audio = null;
    private Button btn_stop_audio = null;

    private SeekBar skb_video=null;
    private Button btn_start_video = null;
    private Button btn_stop_video = null;
    private SurfaceView surfaceView;
    private SurfaceHolder surfaceHolder;

    private MediaPlayer m = null;
    private Timer mTimer;
    private TimerTask mTimerTask;

    private boolean isChanging=false;//互斥变量，防止定时器与SeekBar拖动时进度冲突
     @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        //----------Media控件设置---------//
        m=new MediaPlayer();

        //播放结束之后弹出提示
        m.setOnCompletionListener(new MediaPlayer.OnCompletionListener(){
                        @Override
                        public void onCompletion(MediaPlayer arg0) {
                                Toast.makeText(testMedia.this, "结束", 1000).show();
                                m.release();
                        }
        });

      //----------定时器记录播放进度---------//
        mTimer = new Timer();
        mTimerTask = new TimerTask() {
            @Override
            public void run() {
                    if(isChanging==true)
                            return;

                    if(m.getVideoHeight()==0)
                            skb_audio.setProgress(m.getCurrentPosition());
                    else
                            skb_video.setProgress(m.getCurrentPosition());
            }
        };

        mTimer.schedule(mTimerTask, 0, 10);

        btn_start_audio = (Button) this.findViewById(R.id.Button01);
        btn_stop_audio = (Button) this.findViewById(R.id.Button02);
        btn_start_audio.setOnClickListener(new ClickEvent());
        btn_stop_audio.setOnClickListener(new ClickEvent());
        skb_audio=(SeekBar)this.findViewById(R.id.SeekBar01);
        skb_audio.setOnSeekBarChangeListener(new SeekBarChangeEvent());

        btn_start_video = (Button) this.findViewById(R.id.Button03);
        btn_stop_video = (Button) this.findViewById(R.id.Button04);
        btn_start_video.setOnClickListener(new ClickEvent());
        btn_stop_video.setOnClickListener(new ClickEvent());
        skb_video=(SeekBar)this.findViewById(R.id.SeekBar02);
        skb_video.setOnSeekBarChangeListener(new SeekBarChangeEvent());
        surfaceView = (SurfaceView) findViewById(R.id.SurfaceView01);
        surfaceHolder = surfaceView.getHolder();
        surfaceHolder.setFixedSize(100, 100);
        surfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
    }

  /*
   * 按键事件处理
   */
  class ClickEvent implements View.OnClickListener{
        @Override
        public void onClick(View v) {
                if(v==btn_start_audio)
                {
                        m.reset();//恢复到未初始化的状态
                        m=MediaPlayer.create(testMedia.this, R.raw.big);//读取音频
                        skb_audio.setMax(m.getDuration());//设置SeekBar的长度
                        try {
                                m.prepare();        //准备
                        } catch (IllegalStateException e) {
                                // TODO Auto-generated catch block
                                e.printStackTrace();
                        } catch (IOException e) {
                                // TODO Auto-generated catch block
                                e.printStackTrace();
                        }
                        m.start();        //播放
                }
                else if(v==btn_stop_audio || v==btn_stop_video)
                {
                        m.stop();
                }
                else if(v==btn_start_video)
                {
                        m.reset();//恢复到未初始化的状态
                        m=MediaPlayer.create(testMedia.this, R.raw.test);//读取视频
                        skb_video.setMax(m.getDuration());//设置SeekBar的长度
                        m.setAudioStreamType(AudioManager.STREAM_MUSIC);
                        m.setDisplay(surfaceHolder);//设置屏幕

                        try {
                            m.prepare();

                        } 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();
                        }
                        m.start();
                }
        }
  }

  /*
   * SeekBar进度改变事件
   */
  class SeekBarChangeEvent implements SeekBar.OnSeekBarChangeListener{

        @Override
        public void onProgressChanged(SeekBar seekBar, int progress,
                        boolean fromUser) {
                // TODO Auto-generated method stub

        }

        @Override
        public void onStartTrackingTouch(SeekBar seekBar) {
            isChanging=true;
        }

        @Override
        public void onStopTrackingTouch(SeekBar seekBar) {
                m.seekTo(seekBar.getProgress());
            isChanging=false;
        }

  }

}