Show an undo button after deleting a gpu driver

After a driver has been deleted, a snackbar will be shown confirming the deletion, with an button to undo it.

app/src/main/java/emu/skyline/adapter/GenericAdapter.kt

@@ -73,6 +73,11 @@ open class GenericAdapter : RecyclerView.Adapter<GenericViewHolder<ViewBinding>>
         filter.filter(currentSearchTerm)
     }
 
+    open fun addItemAt(position : Int, item : GenericListItem<out ViewBinding>) {
+        allItems.add(position, item)
+        filter.filter(currentSearchTerm)
+    }
+
     fun setOnFilterPublishedListener(listener : OnFilterPublishedListener) {
         onFilterPublishedListener = listener
     }
@@ -168,7 +173,7 @@ class SelectableGenericAdapter(private val defaultPosition : Int) : GenericAdapt
     /**
      * Removes the item at [position] from the list and updates the selected position accordingly
      */
-    override fun removeItemAt(position: Int) {
+    override fun removeItemAt(position : Int) {
         super.removeItemAt(position)
         if (position < selectedPosition)
             selectedPosition--

app/src/main/java/emu/skyline/adapter/GpuDriverViewItem.kt

@@ -15,8 +15,8 @@ object GpuDriverBindingFactory : ViewBindingFactory {
 
 open class GpuDriverViewItem(
     val driverMetadata : GpuDriverMetadata,
-    private val onDelete : ((wasChecked : Boolean) -> Unit)? = null,
-    private val onClick : (() -> Unit)? = null
+    var onDelete : ((position : Int, wasChecked : Boolean) -> Unit)? = null,
+    var onClick : (() -> Unit)? = null
 ) : SelectableGenericListItem<GpuDriverItemBinding>() {
     private var position = -1
 
@@ -42,15 +42,15 @@ open class GpuDriverViewItem(
             onClick?.invoke()
         }
 
-        if (onDelete != null) {
+        onDelete?.let { onDelete ->
             binding.deleteButton.visibility = ViewGroup.VISIBLE
             binding.deleteButton.setOnClickListener {
                 val wasChecked = position == selectableAdapter?.selectedPosition
                 selectableAdapter?.removeItemAt(position)
 
-                onDelete.invoke(wasChecked)
+                onDelete.invoke(position, wasChecked)
             }
-        } else {
+        } ?: run {
             binding.deleteButton.visibility = ViewGroup.GONE
         }
     }

app/src/main/java/emu/skyline/preference/GpuDriverActivity.kt

@@ -79,17 +79,36 @@ class GpuDriverActivity : AppCompatActivity() {
         }
 
         GpuDriverHelper.getInstalledDrivers(this).onEachIndexed { index, (file, metadata) ->
-            items.add(GpuDriverViewItem(metadata, { wasChecked ->
-                if (wasChecked) {
-                    // If the deleted driver was the selected one, select the system driver
-                    preferenceSettings.gpuDriver = PreferenceSettings.SYSTEM_GPU_DRIVER
+            items.add(GpuDriverViewItem(metadata).apply {
+                onDelete = { position, wasChecked ->
+                    // If the driver was selected, select the system driver as the active one
+                    if (wasChecked)
+                        preferenceSettings.gpuDriver = PreferenceSettings.SYSTEM_GPU_DRIVER
+
+                    Snackbar.make(binding.root, "${metadata.label} deleted", Snackbar.LENGTH_LONG).setAction(R.string.undo) {
+                        this@GpuDriverActivity.adapter.run {
+                            addItemAt(position, this@apply)
+                            // If the item was selected before removal, set it back as the active one when undoing
+                            if (wasChecked) {
+                                // Only notify previous to avoid notifying items before indexes have updated, the newly inserted item will be updated on bind
+                                selectAndNotifyPrevious(position)
+                                preferenceSettings.gpuDriver = metadata.label
+                            }
+                        }
+                    }.addCallback(object : Snackbar.Callback() {
+                        override fun onDismissed(transientBottomBar : Snackbar?, event : Int) {
+                            // Only delete the driver directory if the user didn't undo the deletion
+                            if (event != DISMISS_EVENT_ACTION) {
+                                file.deleteRecursively()
+                            }
+                        }
+                    }).show()
                 }
-                if (!file.deleteRecursively()) {
-                    Snackbar.make(binding.root, getString(R.string.gpu_driver_delete_failed), Snackbar.LENGTH_LONG).show()
+
+                onClick = {
+                    preferenceSettings.gpuDriver = metadata.label
                 }
-            }, {
-                preferenceSettings.gpuDriver = metadata.label
-            }))
+            })
 
             if (preferenceSettings.gpuDriver == metadata.label) {
                 adapter.selectedPosition = index + 1 // Add 1 to account for the system driver entry

app/src/main/res/values/strings.xml

@@ -184,4 +184,5 @@
     <!-- Misc -->
     <!--suppress AndroidLintUnusedResources -->
     <string name="expand_button_title" tools:override="true">Expand</string>
+    <string name="undo">Undo</string>
 </resources>