added scroll position save and restore in favorites tab

app/src/main/java/awais/instagrabber/fragments/FavoritesFragment.kt

@@ -2,6 +2,7 @@ package awais.instagrabber.fragments
 
 import android.content.DialogInterface
 import android.os.Bundle
+import android.os.Handler
 import android.util.Log
 import android.view.LayoutInflater
 import android.view.View
@@ -23,6 +24,8 @@ import com.google.android.material.dialog.MaterialAlertDialogBuilder
 class FavoritesFragment : Fragment() {
     private var shouldRefresh = true
 
+    private var scrollPosition = 0
+
     private lateinit var binding: FragmentFavoritesBinding
     private lateinit var root: RecyclerView
     private lateinit var adapter: FavoritesAdapter
@@ -46,11 +49,19 @@ class FavoritesFragment : Fragment() {
         shouldRefresh = false
     }
 
+    override fun onPause() {
+        super.onPause()
+        scrollPosition = (root.getLayoutManager() as LinearLayoutManager).findLastVisibleItemPosition()
+    }
+
     override fun onResume() {
         super.onResume()
         if (!this::adapter.isInitialized) return
         // refresh list every time in onViewStateRestored since it is cheaper than implementing pull down to refresh
-        favoritesViewModel.list.observe(viewLifecycleOwner, { list: List<Favorite?>? -> adapter.submitList(list) })
+        favoritesViewModel.list.observe(viewLifecycleOwner, {
+            list: List<Favorite?>? -> adapter.submitList(list, Runnable {
+                root.scrollToPosition(scrollPosition)})
+            })
     }
 
     private fun init() {