Retrieve a Fragment from a ViewPager

Question

I\'m using a ViewPager together with a FragmentStatePagerAdapter to host three different fragments:

• [Fragment1]
• [Fragment2]<

Answer 1

I know this has a few answers, but maybe this will help someone. I have used a relatively simple solution when I needed to get a Fragment from my ViewPager. In your Activity or Fragment holding the ViewPager, you can use this code to cycle through every Fragment it holds.

FragmentPagerAdapter fragmentPagerAdapter = (FragmentPagerAdapter) mViewPager.getAdapter();
for(int i = 0; i < fragmentPagerAdapter.getCount(); i++) {
    Fragment viewPagerFragment = fragmentPagerAdapter.getItem(i);
    if(viewPagerFragment != null) {
        // Do something with your Fragment
        // Check viewPagerFragment.isResumed() if you intend on interacting with any views.
    }
}

• If you know the position of your Fragment in the ViewPager, you can just call getItem(knownPosition).

• If you don't know the position of your Fragment in the ViewPager, you can have your children Fragments implement an interface with a method like getUniqueId(), and use that to differentiate them. Or you can cycle through all Fragments and check the class type, such as if(viewPagerFragment instanceof FragmentClassYouWant)

!!! EDIT !!!

I have discovered that getItem only gets called by a FragmentPagerAdapter when each Fragment needs to be created the first time, after that, it appears the the Fragments are recycled using the FragmentManager. This way, many implementations of FragmentPagerAdapter create new Fragments in getItem. Using my above method, this means we will create new Fragments each time getItem is called as we go through all the items in the FragmentPagerAdapter. Due to this, I have found a better approach, using the FragmentManager to get each Fragment instead (using the accepted answer). This is a more complete solution, and has been working well for me.

FragmentPagerAdapter fragmentPagerAdapter = (FragmentPagerAdapter) mViewPager.getAdapter();
for(int i = 0; i < fragmentPagerAdapter.getCount(); i++) {
    String name = makeFragmentName(mViewPager.getId(), i);
    Fragment viewPagerFragment = getChildFragmentManager().findFragmentByTag(name);
    // OR Fragment viewPagerFragment = getFragmentManager().findFragmentByTag(name);
    if(viewPagerFragment != null) {

        // Do something with your Fragment
        if (viewPagerFragment.isResumed()) {
            // Interact with any views/data that must be alive
        }
        else {
            // Flag something for update later, when this viewPagerFragment
            // returns to onResume
        }
    }
}

And you will need this method.

private static String makeFragmentName(int viewId, int position) {
    return "android:switcher:" + viewId + ":" + position;
}