How to know if a Fragment already called onCreateView()

Question

We all know that when using ViewPager with Fragment and FragmentPagerAdapter we get 3 Fragment loaded: the visible one, and both on each of its sides.

So, if I have 7 Fragments and I'm iterating through them to see which 3 of them are the ones that are loaded, and by that I mean onCreateView() has already been called, how can I determine this?

EDIT: The Fragment doesn't have to be the one that the ViewPager is showing, just that onCreateView() has already been called.

Answer 1

Well logically, this would be a reasonable test if onCreateView has been called:

myFragment.getView() != null;

Assuming you a have a reference to all of the fragments in the pager iterate, them and check if they have a view.

http://developer.android.com/reference/android/app/Fragment.html#getView()

Update

The above answer assumes that your fragments always create a view, and are not viewless fragments. If they are then I suggest sub classing the fragment like so:

public abstract class SubFragment extends Fragment
{
    protected boolean onCreateViewCalled = false;

    public boolean hasOnCreateViewBeenCalled()
    {
        return onCreateViewCalled;
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup Container, Bundle state){
        onCreateViewCalled = true;
        return null;
    }
}

Just bear in mind that further sub classes will have to call super or set the flag themselves should they override onCreateView as well.

Answer 2

I added an interface to Fragment. Looks like:

protected OnCreateViewCallback createViewCallback = null;

public void setCreateViewCallback(OnCreateViewCallback createViewCallback) {
    this.createViewCallback = createViewCallback;
}

public interface OnCreateViewCallback {

    void onCreateView();

}

In my onCreateView():

    //initialize your view.
    if (createViewCallback != null) {
        createViewCallback.onCreateView();
        createViewCallback = null;
    }
    return mainView;

From my activity:

        if (ocrFragment.getView() == null) {
            ocrFragment.setCreateViewCallback(new MainScreenFragment.OnCreateViewCallback() {
                @Override
                public void onCreateView() {
                    ocrFragment.ocrImage(picture, false);
                }
            });
        } else {
            ocrFragment.ocrImage(picture, false);
        }