Foreground Service dont run constantly

问题

In my app I use a foreground service that must run constantly. Sometimes the foreground service is stopped. Under what circumstances can the OS kill my service (it happen even if there is enough memory, battery is full, phone is charging)?

This is what my code looks like until now:

public class ServiceTest extends Service {

    public static Thread serverThread = null;
    public Context context = this;

    public ServiceTest(Context context) {
        super();
        this.context = context;
    }

    public ServiceTest() {

    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        super.onStartCommand(intent, flags, startId);

        if (this.serverThread == null) {
            this.serverThread = new Thread(new ThreadTest());
            this.serverThread.start();
        }

        return START_STICKY;
    }

    private class ThreadTest implements Runnable {

        @Override
        public void run() {
            Intent notificationIntent = new Intent(context, MainActivity.class);
        notificationIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK);
        PendingIntent pendingIntent = PendingIntent.getActivity(context, 0,
                notificationIntent, PendingIntent.FLAG_CANCEL_CURRENT);

        Notification notification = new NotificationCompat.Builder(context)
                .setContentTitle("Notification title")
                .setContentText("Notification text")
                .setContentIntent(pendingIntent)
                .setAutoCancel(false)
                .setSmallIcon(R.drawable.android)
                .setOngoing(true).build();

                startForeground(101, notification);

                while(true){
                    //work to do
                }
        }


    }

    @Nullable
    @Override
    public IBinder onBind(Intent intent) {
        return null;
    }

}

回答1:

There is not a single... Many problems in your code... You may be getting it "0 Errors" as it is syntactically correct but it is androidicaly wrong, your basics are poor, reading of android documentation and implementation is very poor. Android never runs very poor things...

Problem : 1

Do you know for a service conventionally you should override onCreate, onStartCommand, onBind, onDestroy methods....?

I don't see onDestroy there....!!

Problem : 2

Do you know how to notify...? Your onStartCommand implementation is again making no sense.

KEEP IT EMPTY JUST RETURN START_STICKY

Problem : 3

How do you expect to run this under background execution limits...? Notify android first by making notification in oncreate only and with startforeground if needed...

I don't see it there.... you trying to do it in onstartcommand and again it is very poorly...

Well... take a look at working code below :

public class RunnerService extends Service
{
NotificationManager mNotifyManager;
NotificationCompat.Builder mBuilder;
NotificationChannel notificationChannel;
String NOTIFICATION_CHANNEL_ID = "1";

public RunnerService() { }

@Override
public void onCreate()
{
    super.onCreate();

    Log.d("RUNNER : ", "OnCreate... \n");

    Bitmap IconLg = BitmapFactory.decodeResource(getResources(), R.drawable.ic_launcher_foreground);

    mNotifyManager = (NotificationManager) getApplicationContext().getSystemService(NOTIFICATION_SERVICE);
    mBuilder = new NotificationCompat.Builder(this, null);
    mBuilder.setContentTitle("My App")
            .setContentText("Always running...")
            .setTicker("Always running...")
            .setSmallIcon(R.drawable.ic_menu_slideshow)
            .setLargeIcon(IconLg)
            .setPriority(Notification.PRIORITY_HIGH)
            .setVibrate(new long[] {1000})
            .setVisibility(Notification.VISIBILITY_PUBLIC)
            .setOngoing(true)
            .setAutoCancel(false);

    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O)
    {
        notificationChannel = new NotificationChannel(NOTIFICATION_CHANNEL_ID, "My Notifications", NotificationManager.IMPORTANCE_HIGH);

        // Configure the notification channel.
        notificationChannel.setDescription("Channel description");
        notificationChannel.enableLights(true);
        notificationChannel.setLightColor(Color.RED);
        notificationChannel.setVibrationPattern(new long[]{1000});
        notificationChannel.enableVibration(true);
        notificationChannel.setLockscreenVisibility(Notification.VISIBILITY_PUBLIC);
        mNotifyManager.createNotificationChannel(notificationChannel);

        mBuilder.setChannelId(NOTIFICATION_CHANNEL_ID);
        startForeground(1, mBuilder.build());
    }
    else
    {
        mBuilder.setChannelId(NOTIFICATION_CHANNEL_ID);
        mNotifyManager.notify(1, mBuilder.build());
    }
}

@Override
public int onStartCommand(Intent intent, int flags, int startId)
{
    Log.d("RUNNER : ", "\nPERFORMING....");

    return START_STICKY;
}

@Override
public void onDestroy()
{
    Log.d("RUNNER : ", "\nDestroyed....");
    Log.d("RUNNER : ", "\nWill be created again automaticcaly....");
    super.onDestroy();
}


@Override
public IBinder onBind(Intent intent)
{
    // TODO: Return the communication channel to the service.
    throw new UnsupportedOperationException("NOT_YET_IMPLEMENTED");
}
}

How to check....???

Remove the app from recents list and you should see in your logs the "Performing " message in logcat...

In what conditions it stops...?

It never stops ( until next boot..!! )... Yes it stops when user force stops application. And rarely if system finds it is having very low resources .... which is a very rare condition seems to occur as android has improved a lot over the time....

How to start it....?????

Wherever it may be from mainactivity or from receiver or from any class :

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O)
        {
            context.startForegroundService(new Intent(context, RunnerService.class));

        }
        else
        {
            context.startService(new Intent(context, RunnerService.class));

        }

How to check is service started or not....?

Simply Don't..... Even if you starts service how many times you wants.... If it is already running... then it won't be start again.... If not running then... will start it...!!

来源：https://stackoverflow.com/questions/51823543/foreground-service-dont-run-constantly