如何保证service不被系统杀死

参考：http://blog.csdn.net/yyingwei/article/details/8509402

http://www.cnblogs.com/ylligang/articles/2665181.html

1. onStartCommand 中返回 START_STICKY

public int onStartCommand(Intent intent, int flags, int startId) {
return START_STICKY;
}

2.onDestroy 中重新启动（ settings 中stop service会调用service onDestroy方法）

public void onDestroy() { 
Intent localIntent = new Intent();
localIntent.setClass(this, MyService.class); //销毁时重新启动Service
this.startService(localIntent);
｝

3.提升服务优先级 前台服务

一个已启动的service可以调用startForeground(int, Notification)将service置为foreground状态，调用stopForeground(boolean)将service置为 background状态。 
　　我们会在调用startForeground(int, Notification)传入参数notification，它会在状态栏里显示正在进行的foreground service。background service不会在状态栏里显示。

Notification notification =newNotification(R.drawable.icon, getText(R.string.ticker_text),System.currentTimeMillis());Intent notificationIntent =newIntent(this,ExampleActivity.class);PendingIntent pendingIntent =PendingIntent.getActivity(this,0, notificationIntent,0);
notification.setLatestEventInfo(this, getText(R.string.notification_title),
        getText(R.string.notification_message), pendingIntent);
startForeground(ONGOING_NOTIFICATION, notification);

在AndroidManifest.xml文件中对于intent-filter可以通过android:priority = "1000"这个属性设置最高优先级

4.broadcastReceiver 启动

开机启动ndroid.intent.action.BOOT_COMPLETED