How to get reference of currently visible activity without passing it as parameter to other class

Question

As the title says, I want to get the reference of currently visible activity or you can say activity which is at the top of backstack from a class, I don't want to send activity reference to that class, because I am using that class from many activities and if I do, I have to pass activity reference from every activity which is a long process.

I already have seen many answers which are typecasting context reference to activity but it is not working.

If anyone has the idea of how to do that in a short way, then please share.

Answer 1

I have found a way via we can do this, In your application class add: registerActivityLifecycleCallbacks(this will listen to all activity lifecycle methods), like this:

public class MyApplication extends Application {

    public static Activity currentActivity=null;

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

        registerActivityLifecycleCallbacks(new ActivityLifecycleCallbacks() {
            @Override
            public void onActivityCreated(@NonNull Activity activity, @Nullable Bundle bundle) {

            }

            @Override
            public void onActivityStarted(@NonNull Activity activity) {
                currentActivity=activity;
            }

            @Override
            public void onActivityResumed(@NonNull Activity activity) {

            }

            @Override
            public void onActivityPaused(@NonNull Activity activity) {

            }

            @Override
            public void onActivityStopped(@NonNull Activity activity) {

            }

            @Override
            public void onActivitySaveInstanceState(@NonNull Activity activity, @NonNull Bundle bundle) {

            }

            @Override
            public void onActivityDestroyed(@NonNull Activity activity) {

            }
        });
    }
}

And then use it like:

 if (MyApplication.currentActivity!=null){
             // your code here
        }

Don't forget to add your application class to manifest:

 <application
        android:name=".MyApplication"
        .../>