Android提高第一篇之MediaPlayer

 

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

        前面写了十四篇关于界面的入门文章，大家都看完和跟着练习之后，对于常用的Layout和View都会有一定的了解了,接下来的文章就不再强调介绍界面了，而是针对具体的常见功能而展开。

        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 version="1.0" encoding="utf-8"?>  <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"></SeekBar>      <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>          <Button android:id="@+id/Button02" android:layout_width="wrap_content"              android:layout_height="wrap_content" android:text="停止播放"></Button>      </LinearLayout>      <SeekBar android:id="@+id/SeekBar02" android:layout_height="wrap_content"          android:layout_width="fill_parent"></SeekBar>        <SurfaceView android:id="@+id/SurfaceView01"          android:layout_width="fill_parent" android:layout_height="250px"></SurfaceView>      <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>          <Button android:layout_width="wrap_content"              android:layout_height="wrap_content" android:text="停止播放" android:id="@+id/Button04"></Button>      </LinearLayout>  </LinearLayout>  

 

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;         }            }    }