android用听筒不断播放音乐

     <p>这个小应用常用于测试手机的听筒寿命。</p>    <p>MainActivity:</p>    <pre class="brush:java; toolbar: true; auto-links: false;">package morgen.headphone; import java.io.File; import android.app.Activity; import android.content.Context; import android.media.AudioManager; import android.media.MediaPlayer; import android.media.MediaPlayer.OnPreparedListener; import android.os.Bundle; import android.os.Environment; import android.view.View; import android.widget.EditText; import android.widget.Toast; public class MainActivity extends Activity {  private EditText nameText;  private String path;  private MediaPlayer mediaPlayer;  @Override  public void onCreate(Bundle savedInstanceState) {  super.onCreate(savedInstanceState);  setContentView(R.layout.main);  mediaPlayer = new MediaPlayer();  nameText = (EditText) this.findViewById(R.id.filename);  }   @Override  protected void onDestroy() {  mediaPlayer.release();  mediaPlayer = null;  super.onDestroy();  }   public void mediaplay(View v) {  switch (v.getId()) {  case R.id.playbutton:  String filename = nameText.getText().toString();  File audio = new File(Environment.getExternalStorageDirectory(), filename);  if (audio.exists()) {  AudioManager audioManager = (AudioManager) this.getSystemService(Context.AUDIO_SERVICE);  audioManager.setMode(AudioManager.MODE_IN_CALL);// 把模式调成听筒放音模式  path = audio.getAbsolutePath();  play(0);  // 设置音频循环播放   mediaPlayer.setLooping(true);  } else {  path = null;  Toast.makeText(getApplicationContext(), R.string.filenoexist, 1).show();  }  break;   case R.id.stopbutton:  if (mediaPlayer.isPlaying())  mediaPlayer.stop();  AudioManager audioManager = (AudioManager) this.getSystemService(Context.AUDIO_SERVICE);  audioManager.setMode(AudioManager.MODE_NORMAL);  break;  }  }   private void play(int position) {  try {  mediaPlayer.reset();// 把各项参数恢复到初始状态  mediaPlayer.setDataSource(path);  mediaPlayer.prepare();// 进行缓冲  mediaPlayer.setOnPreparedListener(new PrepareListener(position));  } catch (Exception e) {  e.printStackTrace();   }  }   private final class PrepareListener implements OnPreparedListener {  private int position;  public PrepareListener(int position) {  this.position = position;  }   public void onPrepared(MediaPlayer mp) {  mediaPlayer.start();// 开始播放  if (position > 0)  mediaPlayer.seekTo(position);  }  } }</pre>    <p></p>    <p>布局文件：</p>    <p>main.xml:</p>    <pre class="brush:xml; toolbar: true; auto-links: false;"><?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"     android:orientation="vertical"     android:layout_width="fill_parent"     android:layout_height="fill_parent"     >  <TextView       android:layout_width="fill_parent"      android:layout_height="wrap_content"      android:text="@string/filename"     />          <EditText     android:layout_width="fill_parent"      android:layout_height="wrap_content"      android:text="tianzhao.mp3"     android:id="@+id/filename"     />      <LinearLayout     android:orientation="horizontal"     android:layout_width="fill_parent"     android:layout_height="wrap_content"     >      <Button       android:layout_width="100dip"       android:layout_height="60dip"       android:text="@string/playbutton"       android:onClick="mediaplay"       android:id="@+id/playbutton"       />  <Button      android:layout_width="100dip"       android:layout_height="60dip"       android:text="@string/stopbutton"       android:onClick="mediaplay"       android:id="@+id/stopbutton"       />             </LinearLayout> </LinearLayout>  &nbsp;</pre>strings.xml:    <pre class="brush:xml; toolbar: true; auto-links: false;"><?xml version="1.0" encoding="utf-8"?>  <resources>     <string name="hello">Hello World, MainActivity!</string>     <string name="app_name">音乐播放器</string>     <string name="filename">音乐文件名称</string>     <string name="playbutton">播放</string>     <string name="stopbutton">停止</string>     <string name="filenoexist">文件没有发现</string> </resources></pre>    <p></p>    <p>最后记得加上权限：</p>    <p><uses-permission android:name="android.permission.MODIFY_AUDIO_SETTINGS"/><br /> </p>    <p></p>    <p></p>