How to test if a fragment view is visible to the user?

Question

I have a ViewPager, each page is a Fragment view. I want to test if a fragment is in a visible region. the Fragment.isVisible only test

• the fragment is attache

Answer 1

This is what I use to determine the visibility of a fragment.

private static boolean m_iAmVisible;

@Override
public void setUserVisibleHint(boolean isVisibleToUser) { 
    super.setUserVisibleHint(isVisibleToUser);
    m_iAmVisible = isVisibleToUser;

    if (m_iAmVisible) { 
        Log.d(localTAG, "this fragment is now visible");
    } else {  
        Log.d(localTAG, "this fragment is now invisible");
    }
}

Answer 2

setUserVisibleHint probably may not be called, onHiddenChanged may be called not every time when another fragment is being closed. So, you may rely on onResume (and onPause), but it is usually called too often (for example, when you turn on a device screen). Also in some situations it is not called, you should manage current fragment in host activity and write:

if (currentFragment != null) {
    currentFragment.onResume();
}

Answer 3

Kotlin:

if (userVisibleHint) {
    // the fragment is visible
} else {
    // the fragment is not visible
}

Java

if (getUserVisibleHint()) {
    // the fragment is visible
} else {
    // the fragment is not visible
}

https://developer.android.com/reference/android/app/Fragment.html#getUserVisibleHint()

https://stackoverflow.com/a/12523627/2069407

Answer 4

If you know what "page" each fragment is attached to you could use ViewPager.getCurrentItem() to determine which fragment is "visible".