Application onCreate() NOT getting called every time

oncreate method in android
android activity
android application life cycle
android activity lifecycle

I have a very important initialization to do when the app starts. I found the best way to do is to put that code inside onCreate() of the class which extends Application class.

class ApplicationDemo extends Application{

@Override
public void onCreate(){
 super.onCreate();
 Log.d("LOG", "Inside onCreate()");
}

}

The Problem

I do not find the log statement to be executed every time the app is run. Like I start the app for the first time, get the log statement, then close the app and start again from the launcher. No, the log statement doesn't come.

What is the problem? How can I ensure a particular code is run every time my app is run and before anything else is performed?


My guess is that you truly have open your application just once.

I'm pretty sure that, after you closed your application, it truly just goes into the background, waiting to be put in the foreground again. (It does not get created again, you only reuse something you already have created.)

Try making sure you actually killed the process of your application before re-opening it; to make sure you actually closed & reopen it, and not just do a simple background-foreground thingy.

onCreate() method of Application class not working as expected with , GitHub is home to over 50 million developers working together to But when I do not call any of OneSignal methods, onCreate() method works properly. This will happen any time a Service or BroadcastReceiver is started  OnCreate is useful mainly in stateful applications, because in stateless mode, the page object is reinitialized every time the page is called. If you are working in stateful mode without an explicit navigation path, and if you run the page a second time (reuse the page), the page instance remains constant.


This sounds like an Android activity lifecycle problem. I've included a link about pausing and resuming an activity

http://developer.android.com/training/basics/activity-lifecycle/pausing.html

It looks like when you are exiting the app, your activity is being paused. Likewise when you re enter the app, if the process is still running, the activity is getting resumed rather than recreated.

From here, you can either move the code to the onResume() or you can leave it in onCreate() but make sure that exiting the app kills the process. that could be done by putting

getActivity().finish();
System.exit(0);

in any path that directs the user to the home screen (onBackPressed(), exit buttons, etc.)

for starting, try putting a Log statement in onResume and watch where the two get called.

I hope this helps.

Understanding the Android Application Class, Note that you should never store mutable shared data inside the Application object since that data might disappear or become invalid at any time. Application class MyCustomApplication : Application() { // Called when the application is starting, Overriding this method is totally optional! override fun onCreate() { super. I put some breakpoints in Android Studio and it appears that MainActivity OnCreate is being called every time the app returns to the foreground which shows the splash screen. However, since the react side of the app is already running, nothing executes to hide the splash screen as it did back when the app first started.


In Android you usually do not 'close' an application, but rather suspend it. So, when you run it again, it just pops back. To ensure your app is closed, open the list of running application, find your one and force stop it.

Application, An activity will do all setup of "global" state in onCreate(), and release all remaining interacting with the user, and onStop() to handle no longer being visible on screen. so will not be called in every situation as described in its documentation. memory pressure the system can kill the application process at any time. How can I make sure every time the app is opened onCreate() is executed? You don't. Instead, you use other lifecycle methods that are more appropriate, such as onStart(), which will be called both after onCreate() (when the activity is first created) and when the activity is returning to the foreground from having been in the background.


An application or an activity can exist even if it's UI is not displaying. The onCreate() callback is only called when the object is created anew.

This simply means that "every time an user opens the app from the launcher icon".

Then you should be putting the code in the onResume() callback of your launcher activity declared in the manifest. You can make the launcher activity a thin activity that only does this once-per-activation init and then launches the actual main activity.

Sure, there can be prior code run, such as onCreate() of the Application and onCreate() of the Activity so it won't always be the first thing to run, but it will be guaranteed to run every time you launch from the menu.

Activity, Called when the application is starting, before any activity, service, or receiver lazy initialization of state) since the time spent in this function directly impacts the is not loaded, then both onCreate() methods will be called. Signed in debug mode and it resumes every single time, just like my real app. Signed for release and it has the problem: press home to leave the app, press the icon to launch the app and onCreate is called again.


You can use from bellow code for Kotlin:

override fun onTrimMemory(level: Int) {
    super.onTrimMemory(level)
    when (level) {
        ComponentCallbacks2.TRIM_MEMORY_UI_HIDDEN -> {
            /*
               Release any UI objects that currently hold memory.

               "release your UI resources" is actually about things like caches.
               You usually don't have to worry about managing views or UI components because the OS
               already does that, and that's why there are all those callbacks for creating, starting,
               pausing, stopping and destroying an activity.
               The user interface has moved to the background.
            */
            System.exit(0);
        }
        ComponentCallbacks2.TRIM_MEMORY_RUNNING_MODERATE,
        ComponentCallbacks2.TRIM_MEMORY_RUNNING_LOW,
        ComponentCallbacks2.TRIM_MEMORY_RUNNING_CRITICAL -> {
            /*
               Release any memory that your app doesn't need to run.

               The device is running low on memory while the app is running.
               The event raised indicates the severity of the memory-related event.
               If the event is TRIM_MEMORY_RUNNING_CRITICAL, then the system will
               begin killing background processes.
            */
        }
        ComponentCallbacks2.TRIM_MEMORY_BACKGROUND,
        ComponentCallbacks2.TRIM_MEMORY_MODERATE,
        ComponentCallbacks2.TRIM_MEMORY_COMPLETE -> {
            /*
               Release as much memory as the process can.
               The app is on the LRU list and the system is running low on memory.
               The event raised indicates where the app sits within the LRU list.
               If the event is TRIM_MEMORY_COMPLETE, the process will be one of
               the first to be terminated.
            */
        }

    }
}

And bellow code for Java:

public void onTrimMemory(int level) {

        // Determine which lifecycle or system event was raised.
        switch (level) {

            case ComponentCallbacks2.TRIM_MEMORY_UI_HIDDEN:

                /*
                   Release any UI objects that currently hold memory.

                   "release your UI resources" is actually about things like caches. 
                   You usually don't have to worry about managing views or UI components because the OS 
                   already does that, and that's why there are all those callbacks for creating, starting, 
                   pausing, stopping and destroying an activity.
                   The user interface has moved to the background.
                */
                System.exit(0);
                break;

            case ComponentCallbacks2.TRIM_MEMORY_RUNNING_MODERATE:
            case ComponentCallbacks2.TRIM_MEMORY_RUNNING_LOW:
            case ComponentCallbacks2.TRIM_MEMORY_RUNNING_CRITICAL:

                /*
                   Release any memory that your app doesn't need to run.

                   The device is running low on memory while the app is running.
                   The event raised indicates the severity of the memory-related event.
                   If the event is TRIM_MEMORY_RUNNING_CRITICAL, then the system will
                   begin killing background processes.
                */

                break;

            case ComponentCallbacks2.TRIM_MEMORY_BACKGROUND:
            case ComponentCallbacks2.TRIM_MEMORY_MODERATE:
            case ComponentCallbacks2.TRIM_MEMORY_COMPLETE:

                /*
                   Release as much memory as the process can.
                   The app is on the LRU list and the system is running low on memory.
                   The event raised indicates where the app sits within the LRU list.
                   If the event is TRIM_MEMORY_COMPLETE, the process will be one of
                   the first to be terminated.
                */

                break;

            default:
                /*
                  Release any non-critical data structures.
                  The app received an unrecognized memory level value
                  from the system. Treat this as a generic low-memory message.
                */
                break;
        }
    }

Android: When does application's onCreate() method get called?, Activities form the foundation of every Android app. When Android starts an activity, it calls its onCreate() method. The layout includes a text view showing you how much time has passed, a Start button that starts If your device is extremely low on memory, onDestroy() might not get called before the activity is destroyed. OnCreate is useful mainly in stateful applications, because in stateless mode, the page object is reinitialized every time the page is called. If you are working in stateful mode without an explicit navigation path, and if you run the page a second time (reuse the page), the page instance remains constant.


4. The Activity Lifecycle: Being an Activity, Application without any active components. If an application is restarted by the user, its gets moved to the end of this queue. onCreate() - called before the first components of the application starts onStop(). Called once the activity is no longer visible. Time or CPU intensive shut-down operations, such  This class has onCreate and onOpen callback methods, which are called after database is created and every time database is opened respectively. You can override those methods as shown below to run


Android application and activity life cycle - Tutorial, onCreate is not getting called, and my database tables are not being created. onCreate is) called when the database is created for the first time. I just ran into this problem when developing the first Android app I've worked  And finally, onCreate attaches a listener to the button. Android calls this listener code every time the user presses this button. So, this listener code is listening, for presses of the button. OnRestart is another lifecycle method. It gets called if the activity has been stopped, but is about to be started again.


Android: SQLiteOpenHelper failing to call onCreate (not creating , That makes sense because the user can only focus on one thing at a time while on the go. However, other apps can be started pushing the current app in focus into the In contrast to these extended states, after the system calls onCreate(), The activity lifecycle comes across as being abstract if you have not used finite​  Application processes are created on demand and a lot of things happen before you see your application’s launch activity up and running. Every app runs in its own process: By default, every Android app runs in its own Android process which is nothing but a Linux process which gets one execution thread to start with.