Refreshing multiple Realm instances at once?

Question

I\'m using a setup in which every Presenter that is a retained Fragment has its own Realm instance. However, this essentially means th

Answer 1

A possible way of having an open realm at all times while the application is active.

public class BaseActivity extends AppCompatActivity {
    private CustomApplication customApplication;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        customApplication = (CustomApplication)getApplication();
        if(savedInstanceState == null) {
            customApplication.incrementActivityCounter();
        }
    }

    @Override
    protected void onDestroy() {
        if(isFinishing()) {
            customApplication.decrementActivityCounter();
        }
        super.onDestroy();
    }
}

public class CustomApplication extends Application {
    public static final String TAG = CustomApplication.class.getSimpleName();

    private volatile int activityCounter = 0;

    private Realm realm;

    @Override
    public void onCreate() {
        super.onCreate();
        Log.d(TAG, "Application onCreate() called.");
        initializeRealm();
    }

    public void incrementActivityCounter() {
        if (activityCounter == 0) {
            Log.d(TAG, "Increment: Activity counter was 0, initializing Realm.");
            if(realm == null) {
                initializeRealm();
            }
        }
        activityCounter++;
        Log.d(TAG, "Increment: Activity counter incremented to " + activityCounter + ".");
    }

    public void decrementActivityCounter() {
        activityCounter--;
        Log.d(TAG, "Decrement: Activity counter decremented to " + activityCounter + ".");
        if(activityCounter == 0) {
            realm.close();
            realm = null;
            Log.d(TAG, "Decrement: Activity counter was 0, closed realm.");
        }
    }

    private void initializeRealm() {
        realm = Realm.getInstance(this);
        Log.d(TAG, "Realm initialized.");
    }

    public Realm getRealm() {
        return realm;
    }

    public int getActivityCounter() {
        return activityCounter;
    }

    public void setActivityCounter(int activityCounter) {
        this.activityCounter = activityCounter; //process death
    }
}

And then

public class BaseActivity
        extends AppCompatActivity {
   @Override
    protected void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        outState.putInt("activityCounter", ((CustomApplication) getApplication()).getActivityCounter());
    }

    @Override
    protected void onRestoreInstanceState(Bundle savedInstanceState) {
        super.onRestoreInstanceState(savedInstanceState);
        int activityCounter = savedInstanceState.getInt("activityCounter");
        ((CustomApplication) getApplication()).setActivityCounter(activityCounter); //fix process death initializing activity counter to 0
        Log.d(TAG, "Reset activity counter in application after process death to [" + activityCounter + "]");
    }
}