前面文章已經詳細介紹了Android界面的入門技術，相信大家在看完和跟著練習之后，會對于常用的Layout和View都會有一定的了解了,接下來就不再強調介紹界面了，而是針對具體的常見功能而展開。
本文將介紹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，這需要視情況選擇。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的源碼如下:
<?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>
Java部分源碼有點長，需要大家耐心解讀，詳細程序如下：
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(); //播放結束之后彈出提示 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; } }}新聞熱點
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