获取设置多媒体音量和屏幕亮度

mAudioManager = (AudioManager)getSystemService(Context.AUDIO_SERVICE);
//得到最大音量
mMaxVolume = mAudioManager.getStreamMaxVolume(AudioManager.STREAM_MUSIC);  
//得到当前音量
mVolume = mAudioManager.getStreamVolume(AudioManager.STREAM_MUSIC);  
//改变声音
mAudioManager.setStreamVolume(AudioManager.STREAM_MUSIC, index, 0);

  //得到当前亮度
  mBrightness = getWindow().getAttributes().screenBrightness;  
  //调节屏幕亮度
  WindowManager.LayoutParams wlp = getWindow().getAttributes();
  wlp.screenBrightness = mBrightness + percent;
  if(wlp.screenBrightness > 1.0f){
      wlp.screenBrightness = 1.0f;
  }else if(wlp.screenBrightness < 0.05f){
      wlp.screenBrightness = 0.05f;
  }
  getWindow().setAttributes(wlp);