Android警报音量逐渐增加

Question

我有一个Alarm类，可以按时播放默认的闹钟铃声。我想在一段时间内发出警报音，音量从最小到最大。如何逐渐从最小到最大增加音量。是否有示例代码或项目的链接。请帮帮我

Answer 1

你可以自己做。没有什么复杂的。

触发PendingIntent后，请使用处理程序进行增加。

1. 创建将应用的AudioManager或Context作为参数的类。

     public class VolumeRunnable implements Runnable{
   
   private AudioManager mAudioManager;
   private Handler mHandlerThatWillIncreaseVolume;
   private final static int DELAY_UNTILL_NEXT_INCREASE = 30*1000;//30 seconds between each increment
   VolumeRunnable(AudioManager audioManager, Handler handler){
      this.mAudioManager = audioManager;
      this.mHandlerThatWillIncreaseVolume = handler;
   }
   
   @Override
   public void run(){
      int currentAlarmVolume = mAudioManager.getStreamVolume(AudioManager.STREAM_ALARM);
      if(currentAlarmVolume != mAudioManager.getStreamMaxVolume(AudioManager.STREAM_ALARM)){ //if we havent reached the max
   
      //here increase the volume of the alarm stream by adding currentAlarmVolume+someNewFactor
           mHandlerThatWillIncreaseVolume.postDelayed(this,DELAY_UNTILL_NEXT_INCREASE); //"recursively call this runnable again with some delay between each increment of the volume, untill the condition above is satisfied. 
      }
   
   }
   

   }

2. 触发Runnable后，请致电PendingIntent：

  

someHandler.post（new VolumeRunnable（mAudioManager，someHandler））;

我希望这给了你一个想法。原谅任何错误或错别字。