[Crash] Fatal Exception: java.lang.IllegalStateException: Fragment ~not attached to an activity.

따라가 보자, 왜그런가...

requireActivity() 본체는 아래와 같으며 결국 getActivity() 에서 null 이다. 

    /**
     * Return the {@link FragmentActivity} this fragment is currently associated with.
     *
     * @throws IllegalStateException if not currently associated with an activity or if associated
     * only with a context.
     * @see #getActivity()
     */
    @NonNull
    public final FragmentActivity requireActivity() {
        FragmentActivity activity = getActivity();
        if (activity == null) {
            throw new IllegalStateException("Fragment " + this + " not attached to an activity.");
        }
        return activity;
    }

그렇다면 getActivity() 본체를 보자 

mHost check필요. 

    /**
     * Return the {@link FragmentActivity} this fragment is currently associated with.
     * May return {@code null} if the fragment is associated with a {@link Context}
     * instead.
     *
     * @see #requireActivity()
     */
    @Nullable
    final public FragmentActivity getActivity() {
        return mHost == null ? null : (FragmentActivity) mHost.getActivity();
    }

isAdded 로 재확인 처리 필요. 

    /**
     * Return true if the fragment is currently added to its activity.
     */
    final public boolean isAdded() {
        return mHost != null && mAdded;
    }

 

결국. 문제가 발생하는 코드 수행전 아래의 코드로 방어처리하면될듯. 

if (requireActivity() == null) { 
	return; 
}
if (!isAdded()) { 
	return; 
}
// do something.