关键代码:

public class MyService extends Service {    @Nullable    @Override    public IBinder onBind(Intent intent) {        return null;    }    @Override    public void onCreate() {        Intent notifyIntent = new Intent(this, MainActivity.class);        PendingIntent pendingIntent = PendingIntent.getActivity(this,                0, notifyIntent,0);        Notification notification = new Notification.Builder(this).                setSmallIcon(R.mipmap.ic_launcher).                setContentTitle("通知").                setContentText("我是服务的通知").                setContentIntent(pendingIntent).                setDefaults(Notification.DEFAULT_ALL). // 设置用手机默认的震动或声音来提示                build();        // 设置为前台服务,在系统状态栏显示        startForeground(1, notification);        super.onCreate();    }}