[FIXED] PagingDataAdapter.refresh() not working after fragment navigation

Issue

I am using PagingDataAdapter in one fragment to show user activity. in fragment class level,

private var activityAdapter: ActivityFeedAdapter? = null

in onCreate() I am initializing before use as,

activityAdapter = initAdapter()

also in onCreate(),

this.lifecycleScope.launchWhenResumed {
        viewLifecycleOwner.repeatOnLifecycle(Lifecycle.State.STARTED) {
             viewModel.getActivityFeed().observe(viewLifecycleOwner) {
                 it?.let {
                     activityAdapter?.submitData(lifecycle, it)
                 }
             }
         }
     }

and after onStart(), I am setting a click Listener on a view to refresh pagingdata from the UI as,

binding?.refresh?.setOnClickListener {
            activityAdapter?.refresh()
        }

Everything works fine when I use it for the first load. But after I navigate to some fragment and get back to the same screen, clicking on refresh only handles click event but does not refresh the adapter.

BTW, I have initialized the adapter in onCreate() because I need the adapter to maintain loaded data across screen transitions. Anyone help me...

Solution

I got the bug... :))

In onCreate() I was setting observer with lifecycleOwner as viewLifecycleOwner.

But viewLifecycleOwner is only active from onCreateView() till onDestroyView(). So after navigation to a different fragment and getting back from there, the new observer was not set. The old observer is canceled due to lifecycleOwner is destroyed. So I could refresh more data in PagingDataAdapter.

When setting the observer please rethink which lifecycleOwner is to be used. Hope this might help someone. :)

Answered By - Willey Hute
Answer Checked By - Cary Denson (JavaFixing Admin)