AudioManager audioManager = (AudioManager) getSystemService(AUDIO_SERVICE);

//声音模式 
AudioManager.setRingerMode(AudioManager.RINGER_MODE_NORMAL);
//静音模式 
AudioManager.setRingerMode(AudioManager.RINGER_MODE_SILENT);
//震动模式 
AudioManager.setRingerMode(AudioManager.RINGER_MODE_VIBRATE);

//减少声音音量 
AudioManager.adjustVolume(AudioManager.ADJUST_LOWER, 0);
//调大声音音量 
AudioManager.adjustVolume(AudioManager.ADJUST_RAISE, 0)；
（当传入的第一个参数为 AudioManager.ADJUST_LOWER 时，可将音量调小一个单位，传入 AudioManager.ADJUST_RAISE 时，则可以将音量调大一个单位。）

public void setStreamMute (int streamType, boolean state)

import android.app.Activity; 
import android.app.Service; 
import android.media.AudioManager; 
import android.media.MediaPlayer; 
import android.os.Bundle; 
import android.view.View; 
import android.view.View.OnClickListener; 
import android.widget.Button; 
import android.widget.CompoundButton; 
import android.widget.CompoundButton.OnCheckedChangeListener; 
import android.widget.ToggleButton; 
 
public class AutoActivity extends Activity { 
  Button play, up, down,stop; 
  ToggleButton mute; 
  AudioManager aManager; 
  MediaPlayer mPlayer; 
  boolean flag = true; 
 
  @Override 
  protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_auto); 
 
    aManager = (AudioManager) getSystemService(Service.AUDIO_SERVICE); 
    play = (Button) findViewById(R.id.playBtn); 
    up = (Button) findViewById(R.id.upBtn); 
    down = (Button) findViewById(R.id.downBtn); 
    stop = (Button) findViewById(R.id.stopBtn); 
    mute = (ToggleButton) findViewById(R.id.silenceBtn); 
    // 初始化MediaPlayer对象，准备播放音乐 
    mPlayer = MediaPlayer.create(AutoActivity.this, 
        R.raw.love); 
 
    play.setOnClickListener(new OnClickListener() { 
      //音乐播放和暂停 
      @Override 
      public void onClick(View v) { 
         
        // 设置循环播放 
        if(flag) { 
          play.setText("暂停"); 
          mPlayer.setLooping(true);//音乐的循环播放 
          mPlayer.start(); 
          flag = false; 
        }else { 
          play.setText("播放"); 
          mPlayer.pause(); 
          flag = true; 
        } 
      } 
    }); 
    up.setOnClickListener(new OnClickListener() { 
      //提高音量 
      @Override 
      public void onClick(View v) { 
        // 指定调节音乐的音频，增大音量,而现实音量图形示意 
        aManager.adjustStreamVolume(AudioManager.STREAM_MUSIC, 
            AudioManager.ADJUST_RAISE, AudioManager.FLAG_SHOW_UI); 
      } 
    }); 
    down.setOnClickListener(new OnClickListener() { 
      //降低音量 
      @Override 
      public void onClick(View v) { 
        // 指定调节音乐的音频，降低音量,而现实音量图形示意 
        aManager.adjustStreamVolume(AudioManager.STREAM_MUSIC, 
            AudioManager.ADJUST_LOWER, AudioManager.FLAG_SHOW_UI); 
      } 
    }); 
    stop.setOnClickListener(new OnClickListener() { 
      //停止音乐 
      @Override 
      public void onClick(View v) { 
        mPlayer.stop(); 
        play.setText("播放"); 
        flag = true; 
        mPlayer = MediaPlayer.create(AutoActivity.this, 
            R.raw.love); 
      } 
    }); 
    mute.setOnCheckedChangeListener(new OnCheckedChangeListener() { 
      //静音功能 
      @Override 
      public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) { 
        aManager.setStreamMute(AudioManager.STREAM_MUSIC, isChecked); 
      } 
    }); 
  } 
 
} 

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
  android:layout_width="fill_parent" 
  android:layout_height="wrap_content" > 
 
  <TableLayout 
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:layout_marginTop="360dp" > 
 
    <TableRow> 
 
      <Button 
        android:id="@+id/playBtn" 
        android:layout_width="fill_parent" 
        android:layout_height="wrap_content" 
        android:layout_weight="1" 
        android:text="播放" /> 
 
      <Button 
        android:id="@+id/stopBtn" 
        android:layout_width="fill_parent" 
        android:layout_height="wrap_content" 
        android:layout_weight="1" 
        android:text="停止" /> 
    </TableRow> 
 
    <TableRow> 
 
      <Button 
        android:id="@+id/upBtn" 
        android:layout_width="fill_parent" 
        android:layout_height="wrap_content" 
        android:layout_weight="1" 
        android:text="VOL+" /> 
 
      <Button 
        android:id="@+id/downBtn" 
        android:layout_width="fill_parent" 
        android:layout_height="wrap_content" 
        android:layout_weight="1" 
        android:text="VOL-" /> 
 
      <ToggleButton 
        android:id="@+id/silenceBtn" 
        android:layout_width="fill_parent" 
        android:layout_height="wrap_content" 
        android:layout_weight="1" 
        android:text="静音" 
        android:textColor="#ff0000" /> 
    </TableRow> 
  </TableLayout> 
 
</LinearLayout> 

  MediaPlayer mp = new MediaPlayer();

MediaPlayer mp = MediaPlayer.create(this, R.raw.test);//这时就不用调用setDataSource了

MediaPlayer.create(this, R.raw.test);

mp.setDataSource("/sdcard/test.mp3");

mp.setDataSource("http://www.citynorth.cn/music/confucius.mp3");