Keep an Android service always alive

I have implemented something similar in my own application that what it does is start the service every time it dies and also when the device is restarted:

Class that extends BroadcastReceiver:

public class BootBroadcast extends BroadcastReceiver {

    @Override
    public void onReceive(Context ctx, Intent intent) {
         ctx.startService(new Intent(ctx, MyService.class));

    }

}

In my service itself:

public class MyService extends Service {

    .....

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

    .....

}

In the AndroidManifest.xml:

   <service
        android:name=".MyService"
        android:enabled="true"
        android:exported="true" >
    </service>

    <receiver android:name=".BootBroadcast">
        <intent-filter >
            <action android:name="android.intent.action.BOOT_COMPLETED"/>
        </intent-filter>
    </receiver>

Edit: The service is started in the onCreate of my MainActivity:

    if (!isMyServiceRunning(MyService.class)){ //método que determina si el servicio ya está corriendo o no
        serv = new Intent(ctx,MyService.class); //serv de tipo Intent
        ctx.startService(serv); //ctx de tipo Context
        Log.d("App", "Service started");
    } else {
        Log.d("App", "Service already running");
    }

To keep a service when closing the application, use START_STICKYinonStartCommand()

According to your code I see that you link a service so what you are doing is that your Activity interacts with the service:

bindService(intent, serviceConnection, BIND_AUTO_CREATE);

In this case, what you could do is use a service in the Foreground ( Foreground Service ), which is done through the startForeground() method :

Notification notification = new Notification(R.drawable.icon, getText(R.string.ticker_text),
        System.currentTimeMillis());
Intent notificationIntent = new Intent(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_ID, notification);

The option that I perform regularly through a BroadcastReceiver is the following, you can take this article as an example:

http://androidtrainningcenter.blogspot.mx/2013/05/how-to-make-android-service-unstoppable.html

1) register the service when you start your device, with this you don't have to open the application for it to start:

<receiver android:name="ReceiverCall" >
    <intent-filter>
        <action android:name="com.stackoveflow.myservicio" />
        <action android:name="android.intent.action.BOOT_COMPLETED" />
    </intent-filter>
</receiver>

2) Add in the class BroadcastReceiver code to restart the service again.

public class ReceiverCall extends BroadcastReceiver {

    @Override
    public void onReceive(Context context, Intent intent) {
        Log.i("Servicio", "El servicio se detuvo");
        context.startService(new Intent(context, ServiceTest.class));;
    }

}

3) Create the Android Service class and in onDestroy()implement start the service and define return START_STICKYinonStartCommand() so that the service continues to work after closing the application.

public class MyService extends Service {

    .....

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

        return START_STICKY;
    }

    @Override
    public void onDestroy() {

        Intent intent = new Intent("com.stackoveflow.myservicio");
        intent.putExtra("yourvalue", "torestore");
        sendBroadcast(intent);
    }

}

@Andress Blend for those who need the isMyServiceRunning method.

private boolean isMyServiceRunning(Class<?> serviceClass) {
ActivityManager manager = (ActivityManager) getSystemService(Context.ACTIVITY_SERVICE);
for (RunningServiceInfo service : manager.getRunningServices(Integer.MAX_VALUE)) {
    if (serviceClass.getName().equals(service.service.getClassName())) {
        return true;
    }
}
return false;
}