三种方法让你的Service不被“一键加速”和系统杀掉

基本上大家都知道提高service优先级能够在非常大程度上让你的service免于由于内存不足而被kill，当然系统仅仅是在此时先把优先级低的kill掉，假设内存还是不够，也会把你的service干掉的.
1.android:persistent="true"

常驻内存属性对第三方app无效。以下是官方说明

android:persistent

    Whether or not the application should remain running at all times — "true" if it should, and "false" if not. The default value is "false". Applications should not normally set this flag; persistence mode is intended only for certain system applications.

2.startForeground将其放置前台

Notification notification = new Notification();  
notification.flags = Notification.FLAG_ONGOING_EVENT;  
notification.flags |= Notification.FLAG_NO_CLEAR;  
notification.flags |= Notification.FLAG_FOREGROUND_SERVICE;  
startForeground(1, notification); 

3.能够监听Intent.ACTION_TIME_TIC系统时钟广播。系统每隔一段时间发送这个广播。当service被杀死的时候，隔一段时间通过广播启动
  动态注冊android.intent.action.TIME_TICK监听

  推断service是否启动

	public boolean isServiceRunning(String serviceName)
	{
		ActivityManager manager = (ActivityManager)getSystemService(Context.ACTIVITY_SERVICE); 
	    for (RunningServiceInfo service :manager.getRunningServices(Integer.MAX_VALUE)) 
	    { 
	    	if(serviceName.equals(service.service.getClassName()))
	    	{ 
	    		return true; 
	    	} 
	    }
	    return false;
	}

 接受到广播后推断是否启动该service 若没有启动就启动它

    if(intent.getAction().equals(Intent.ACTION_TIME_TICK))
    {
			
	if (!isServiceRunning(name)) 
	{ 
		Intent mIntent = new Intent(context, MyService.class); 
		context.startService(mIntent); 
	} 
   }