Updated EventPageFragment.kt to have access to its own ViewModel and, by extension, its own reference to the database, which forgoes the need to transport data from EventFragment.kt through StudIPEventPageAdapter.kt to EventPageFragment.kt and allows for filtering for a specific day's items through the database rather than needing to iterate through the list via an extension function manually. Also implemented DiffUtil to perform individual updates rather than calling notifyDataSetChanged() every time a single item has been changed.

app/src/main/java/com/denizk0461/studip/fragment/EventPageFragment.kt

@@ -4,26 +4,25 @@ import android.os.Bundle
 import android.view.LayoutInflater
 import android.view.View
 import android.view.ViewGroup
+import androidx.fragment.app.viewModels
 import androidx.recyclerview.widget.LinearLayoutManager
 import com.denizk0461.studip.adapter.StudIPEventPageAdapter
 import com.denizk0461.studip.adapter.StudIPEventItemAdapter
 import com.denizk0461.studip.databinding.RecyclerViewBinding
 import com.denizk0461.studip.model.StudIPEvent
+import com.denizk0461.studip.sheet.ScheduleUpdateSheet
+import com.denizk0461.studip.viewmodel.EventPageViewModel
 
 /**
  * Fragment that is instantiated by [StudIPEventPageAdapter] to display individual days' pages and
  * their events.
  *
- * @param events            list of all events (still not filtered by day at this point)
- * @param currentDay        current day that is used to show only events of a given day (0 = Monday,
- *                          4 = Friday)
- * @param onClickListener   used for listening to clicks and long presses
+ * @param currentDay    current day that is used to show only events of a given day (0 = Monday,
+ *                      4 = Friday)
  */
 class EventPageFragment(
-    private val events: List<StudIPEvent>,
     private val currentDay: Int,
-    private val onClickListener: StudIPEventItemAdapter.OnClickListener,
-) : AppFragment() {
+) : AppFragment(), StudIPEventItemAdapter.OnClickListener {
 
     // Nullable view binding reference
     private var _binding: RecyclerViewBinding? = null
@@ -34,6 +33,14 @@ class EventPageFragment(
      */
     private val binding get() = _binding!!
 
+    // View model reference for providing access to the database
+    private val viewModel: EventPageViewModel by viewModels()
+
+    /**
+     * Adapter that manages the page's items
+     */
+    private val eventAdapter = StudIPEventItemAdapter(currentDay, this)
+
     // Instantiate the view binding
     override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View {
         _binding = RecyclerViewBinding.inflate(inflater, container, false)
@@ -49,12 +56,32 @@ class EventPageFragment(
 
             /*
              * Create new adapter for every page. Attribute position denotes day that will be set up
-             * by the newly created adapter (0 = Monday, 4 = Friday)
+             * by the newly created adapter (0 = Monday, 4 = Friday, 6 = Sunday)
              */
-            adapter = StudIPEventItemAdapter(events, currentDay, onClickListener) // TODO check if empty
+            adapter = eventAdapter
 
             // Animate creation of new page
             scheduleLayoutAnimation()
         }
+
+        // Set up LiveData observer to refresh the view on update
+        viewModel.getEventsForDay(currentDay).observe(viewLifecycleOwner) { events ->
+//            eventAdapter.setNewItems(events)
+            eventAdapter.setNewData(events)
+        }
+    }
+
+    override fun onClick(event: StudIPEvent) {
+        // TODO implement functionality or delete
+    }
+
+    override fun onLongClick(event: StudIPEvent): Boolean {
+        // Open a bottom sheet to edit the event
+        openBottomSheet(ScheduleUpdateSheet(event, onUpdate = { eventToUpdate ->
+            viewModel.update(eventToUpdate)
+        }, onDelete = { eventToDelete ->
+            viewModel.delete(eventToDelete)
+        }))
+        return true
     }
 }