CODEWITHSUNDEEP
android
anujprashar
anujprashar

Reputation: 6335

Application class onCreate method not running on starting app 2nd time

I am using Application class to share global variables across activites and I am setting them in onCreate method of application class. When I start app variables values are set in onCreate and while using app in activities I am changing values of varables. When I exit app and start it again I am getting old values, the last values of variables set in activities. Thats mean onCreate of Application not running on starting app again. This is code in onCreate method of Application class.

@Override
    public void onCreate() {
        super.onCreate();
        application = this;
        category = 12;
        subCategory =22;
    }

It looks like old application object is still in memory and it is not calling onCreate on starting app 2nd time.

What is need to be done so that onCreate of application class run again or where to initialize variables in application class so that code runs everytime.

Upvotes: 5

Views: 8911

Answers (6)

Vikalp
Vikalp

Reputation: 2171

I had the same problem with my app where onCreate() method of Application class just triggered for the first time when my app is loaded. Daniel's solution of using System.exit(0) did the trick but this solution lead me to another problem. After using System.exit(0), onPause(), onStop() and onDestroy() method of my foreground activity did not get called.

Well, that was a reasonable behavior for an app because If you use System.exit(0) then you application will be removed from System's process queue and there will be no way for an android to execute onPause(), onStop() and onDestroy() method for my foreground activity.

The workaround I used for this problem was to finish my activity when back button is pressed and after some time killing my applications process like below:

public void killApp(){
    final Thread threadKillApp = new Thread(new Runnable() {
        @Override
        public void run() {
            try {
                Thread.sleep(1000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            Log.i(TAG, "Going to kill app");
            android.os.Process.killProcess(android.os.Process.myPid());
        }
    });
    threadKillApp.start();
}

Calling killApp() method just after calling finish() on my activity did the job.

Upvotes: -1

Narender Gusain
Narender Gusain

Reputation: 2480

please declare your application class name in manifest file. like below

<application
    android:name="com.tt.app.TTApplication"
    android:label="@string/app_name"

Upvotes: 7

Daniel
Daniel

Reputation: 1012

In the Application class, the onCreate() method is called only if the process was ended when you exited the application. Usually the process is stopped when the system needs memory or if you exit the app using the back button instead of the home button. However, you cannot rely on it being terminated.

However, the right way of passing parameters between activities are intents or preferences. In your case, I have the feeling that preferences is the way to go.

If you really want to kill your process when exiting the application, you can call System.exit(0); when the user presses the back key on your first activity. This is definitely not recommended since it means fighting against the way the Android OS works and might cause problems.

More on this here: Is quitting an application frowned upon?

Upvotes: 1

Dawid Sajdak
Dawid Sajdak

Reputation: 3084

try to use onStart() method or onResume().

Your onCreate method should look like this:

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(someView);
}

your onResume Method should look like this:

@Override
public void onResume() {
    super.onResume();
    variable = someVariable;
}

Upvotes: -3

Hades
Hades

Reputation: 3936

There is probably an instance of your application still in the memory.

Recheck your life cycle methods and make sure that the application is exiting properly.

Also check if any of your activities are leaking memory.

Upvotes: 0

Mohamed_AbdAllah
Mohamed_AbdAllah

Reputation: 5322

Check the Activity life cycle. Do what you want in onResume() instead.

Upvotes: -3

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