How to make a ViewPager loop?

by

One possibility is setting up the screens like this:

C’ A B C A’

C’ looks just like C, but when you scroll to there, it switches you to the real C.
A’ looks just like A, but when you scroll to there, it switches you to the real A.

I would do this by implementing onPageScrollStateChanged like so:

@Override
public void onPageScrollStateChanged (int state) {
    if (state == ViewPager.SCROLL_STATE_IDLE) {
        int curr = viewPager.getCurrentItem();
        int lastReal = viewPager.getAdapter().getCount() - 2;
        if (curr == 0) {
            viewPager.setCurrentItem(lastReal, false);
        } else if (curr > lastReal) {
            viewPager.setCurrentItem(1, false);
        }
    }
}

Note that this calls the alternate form of setCurrentItem and passes false to cause the jump to happen instantly rather than as a smooth scroll.

There are two main drawbacks I see to this. Firstly, upon reaching either end the user has to let the scrolling settle before they can go further. Secondly, it means having a second copy of all of the views in your first and last page. Depending on how resource-heavy your screens are, that may rule out this technique as a possible solution.

Note also that since the view pager doesn’t let clicks go through to underlying controls until after the scrolling has settled, it’s probably fine to not set up clicklisteners and the like for the A’ and C’ fragments.

Edit: Having now implemented this myself, there’s another pretty major drawback. When it switches from A’ to A or C’ to C, the screen flickers for a moment, at least on my current test device.

More Related Contents:

  1. Android Studio – Firebase Fatal error
  2. Send data from activity to fragment in Android
  3. Best practice for instantiating a new Android Fragment
  4. ViewPager and fragments — what’s the right way to store fragment’s state?
  5. How do I add a Fragment to an Activity with a programmatically created content view
  6. Dynamically changing the fragments inside a fragment tab host?
  7. Fragment MyFragment not attached to Activity
  8. Problems with Android Fragment back stack
  9. getView returning null when fragment has been created from an activity
  10. Fragment onResume() & onPause() is not called on backstack
  11. Show DialogFragment with animation growing from a point
  12. How can I access getSupportFragmentManager() in a fragment?
  13. Fragment in ViewPager using FragmentPagerAdapter is blank the second time it is viewed
  14. Wrong requestCode in onActivityResult
  15. One Activity and all other Fragments [closed]
  16. Android replace the current fragment with another fragment
  17. ViewPager + RecyclerView issue in android
  18. How to use data-binding with Fragment
  19. Fragment pressing back button
  20. Android FragmentTransaction Custom Animation (Unknown Animator Name: Translate)
  21. Fragments – The specified child already has a parent. You must call removeView() on the child’s parent first
  22. Refresh or force redraw the fragment
  23. FragmentPagerAdapter getItem is not called
  24. Android ViewPager padding/margin between page fragments
  25. getParentFragment returning null
  26. How to switch between fragments during onclick?
  27. Setting the orientation for only 1 fragment in my activity while the rest is in portrait
  28. Fragment duplication on Fragment Transaction
  29. FragmentStatePagerAdapter with ChildFragmentManager – FragmentManagerImpl.getFragment results in NullPointerException
  30. Activity vs Fragment Lifecycle [closed]

Leave a Comment