How to know when my app has been killed?

I need to know when the user kills my app (Force stop). I've been reading the android lifecycle, which has the onStop() and onDestroy() functions, these are related to each activity the user ends on my app, but not when the user forces stop or kills my app.

Is there any way to know when the user kills the app?

I have found one way to do this.....

1. Make one service like this

    public class OnClearFromRecentService extends Service {
   
        @Override
        public IBinder onBind(Intent intent) {
            return null;
        }
   
        @Override
        public int onStartCommand(Intent intent, int flags, int startId) {
            Log.d("ClearFromRecentService", "Service Started");
            return START_NOT_STICKY;
        }
   
        @Override
        public void onDestroy() {
            super.onDestroy();
            Log.d("ClearFromRecentService", "Service Destroyed");
        }
   
        @Override
        public void onTaskRemoved(Intent rootIntent) {
            Log.e("ClearFromRecentService", "END");
            //Code here
            stopSelf();
        }
    }
   

2. Register this service in Manifest.xml like this

    <service android:name="com.example.OnClearFromRecentService" android:stopWithTask="false" />
   

3. Then start this service on your splash activity

    startService(new Intent(getBaseContext(), OnClearFromRecentService.class));
   

And now whenever you will clear your app from android recent Then this method onTaskRemoved() will execute.

NOTE: In Android O+ this solution only works when the app is full-time in foreground. After more than 1 minute with the app in background, the OnClearFromRecentService (and all other Services running) will be automatically force-killed by the system so the onTaskRemoved() will not be executed.

there's no way to determine when a process is killed. From https://stackoverflow.com/questions/16013578/how-to-detect-if-android-app-is-force-stopped-or-uninstalled

> When a user or the system force stops your application, the entire > process is simply killed. There is no callback made to inform you that > this has happened. > > When the user uninstalls the app, at first the process is killed, then > your apk file and data directory are deleted, along with the records > in Package Manager that tell other apps which intent filters you've > registered for.

Create a Application class

onCreate()
Called when the application is starting, before any activity, service, or receiver objects (excluding content providers) have been created.
onLowMemory()
This is called when the overall system is running low on memory, and actively running processes should trim their memory usage.
onTerminate()
This method is for use in emulated process environments.

Even if you are application Killed or force stop, again Android will start your Application class

After digging into this problem I found a solution that might help you:

All you need to do is check on the onDestroy method of your BaseActivity that is extended by all your activities whether the last running activity of the stack is from your package or not with the following code:

ActivityManager activityManager = (ActivityManager) getSystemService( ACTIVITY_SERVICE );
    
List<ActivityManager.RunningTaskInfo> taskList = activityManager.getRunningTasks( 10 );
    
if ( !taskList.isEmpty() )
    {
     ActivityManager.RunningTaskInfo runningTaskInfo = taskList.get( 0 );
      if ( runningTaskInfo.topActivity != null && 
              !runningTaskInfo.topActivity.getClassName().contains(
                    "com.my.app.package.name" ) )
         {
        //You are App is being killed so here you can add some code
         }
    }

for some cases, you can create splash screen page to determine if app has been killed previously by system.

it basically a screen with intent filter main/launcher, and will be finished, and changed to main activity.

so, every time user visit splashScreen, it shows that the app has been killed before, and you can do anything you want to handle.

sample code:

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    package="id.gits.yourpackage">

    <application
        android:name=".App">
        <activity android:name=".SplashActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <action android:name="android.intent.action.VIEW" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>
</manifest>

SplashActivity:

class SplashActivity : AppCompatActivity() {
    override fun onCreate() {
        super.onCreate()
        doSomethingAfterAppKilled()
    }
}

This might help many, who wants to know if the app is terminated or not The best way is to keep data in one static variable for eg: public static string IsAppAvailable;

the specialty about the static variable is that the data in the static variable contains till the app is in foreground or background, once the app is killed the data in the static variable is erased. Basically, the static variable is reinitialized when the app is freshly created

Create one static class file say Const

namespace YourProject
{
    public static class Const
    {
        public static string IsAppAvailable;
     }
}

In MainActivity

   protected override void OnResume()
    {
       if(string.IsNullOrWhiteSpace(Const.IsAppAvailable))
       {
          //Your app was terminated
       }
       Const.IsAppAvailable = "Available" 
    }

Hope this is helpful to the developers :) Happy coding

I have alternate idea.i have same problem like you.above methods not fix.my problem : "i want to clear all saved data entire app,when user completely close the app"

So, i added clear() & clear saved data(from shared preference or tinyDB) in Application class.