前面寫瞭十四篇關於界面的入門文章，大傢都看完和跟著練習之後，對於常用的Layout和View都會有一定的瞭解瞭,接下來的文章就不再強調介紹界面瞭，而是針對具體的常見功能而展開。
本文介紹MediaPlayer的使用。MediaPlayer可以播放音頻和視頻，另外也可以通過VideoView來播放視頻，雖然VideoView比MediaPlayer簡單易用，但定制性不如用MediaPlayer，要視情況選擇瞭。MediaPlayer播放音頻比較簡單，但是要播放視頻就需要SurfaceView。SurfaceView比普通的自定義View更有繪圖上的優勢，它支持完全的OpenGL ES庫。
先貼出本文程序運行結果的截圖，上面是播放/停止音頻，可用SeekBar來調進度，下面是播放/停止視頻，也是用SeekBar來調進度：
main.xml的源碼:
[xhtml] view plaincopyprint?
<?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="播放音頻"></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="播放視頻"></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>
<?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="播放音頻"></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="播放視頻"></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>
本文程序的源碼，有點長：
[java] view plaincopyprint?
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;//互斥變量，防止定時器與SeekBar拖動時進度沖突
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
//———-Media控件設置———//
m=new MediaPlayer();
//播放結束之後彈出提示
m.setOnCompletionListener(new MediaPlayer.OnCompletionListener(){
@Override
public void onCompletion(MediaPlayer arg0) {
Toast.makeText(testMedia.this, "結束", 1000).show();
m.release();
}
});
//———-定時器記錄播放進度———//
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);
}
/*
* 按鍵事件處理
*/
class ClickEvent implements View.OnClickListener{
@Override
public void onClick(View v) {
if(v==btn_start_audio)
{
m.reset();//恢復到未初始化的狀態
m=MediaPlayer.create(testMedia.this, R.raw.big);//讀取音頻
skb_audio.setMax(m.getDuration());//設置SeekBar的長度
try {
m.prepare(); //準備
} 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();//恢復到未初始化的狀態
m=MediaPlayer.create(testMedia.this, R.raw.test);//讀取視頻
skb_video.setMax(m.getDuration());//設置SeekBar的長度
m.setAudioStreamType(AudioManager.STREAM_MUSIC);
m.setDisplay(surfaceHolder);//設置屏幕
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進度改變事件
*/
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;
}
}
}