21天学习android开发教程之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:

<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：

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;
  }

 }

}

以上就是21天学习android开发教程第一篇关于MediaPlayer的相关介绍，希望对大家的学习有所帮助。