How can I know that onCreateView has been called from an outer class?

Issue

I'm really curious about how to determine (from an outer class) if a fragment's onCreateView() has already been called. I have searched for similar questions but found none.

For instance, is fragment.isAdded() a good indicator?

My first thought was simply fragment.getView() != null, but I'm not 100% sure it would be reliable as it seems, and I'm also slightly reluctant to use it (for no particular reason, I just tend to avoid nullity checks). I would be happy to find a workaround. Suggestions I had:

isAdded()

Return true if the fragment is currently added to its activity.

This line is quite ambiguous in my opinion; added is not attached, but neither created. It might refer to FragmentTransaction.add() (which is semantically wrong because you can have <fragment>s stuck in your layout without having to call add or replace).

Still, FragmentTransaction.add() documentation gives no info nor makes you think added -> created. I'd say no.

isVisible()

Return true if the fragment is currently visible to the user. This means it: (1) has been added, (2) has its view attached to the window, and (3) is not hidden.

Looks good, in the sense that isVisible() -> isCreated, but the third option makes it isCreated != isVisible. I just think of fragments inside a view pager: not all are visible, but the fragments near the currently visible fragment are added, created and alive, you can call methods on them. But for them, isVisible() == false. This is kind of too strict.

isInLayout()

Return true if the layout is included as part of an activity view hierarchy via the < fragment> tag. This will always be true when fragments are created through the < fragment> tag, except in the case where an old fragment is restored from a previous state and it does not appear in the layout of the current state.

I don't think this applies here.

getView() != null

Returns The fragment's root view, or null if it has no layout.

This still looks the one and only solution. I'd just like a confirmation about that.

Implement a callback

..to be called onCreateView() or, better, onViewCreated(). But:

• I don't need to call something as soon as the fragment is created (why would you need that?), I need something to check at a given time;
• One should define the opposite, say, onViewNotAvailableAnymore(), to make the check meaningful at all times;
• I don't see how this would be different, or better, than getView != null.

Solution

Assuming

• you're not interested in whether the Fragment is visible
• you want to know only if the onCreateView(...) method has been called by the Android framework
• you need to use existing Fragment API methods to find out

then use

getView() != null

provided that you inflate the layout and return the View inside onCreateView(...) .

A non-Fragment-API approach is to add a callback in onCreate(...), which you then call in onCreateView() or later (in lifecycle) method.

Answered By - Gunnar Karlsson