From f85f3661448b41b782f468ec8268a46359dd8c0a Mon Sep 17 00:00:00 2001
From: OxygenCobalt <oxycblt@abstractr.net>
Date: Tue, 7 Jun 2022 19:14:54 -0600
Subject: [PATCH] ui: change adapter animations

Rework the submitList animation to be less resource intensive and nicer
looking (at the cost of scroll positioning)

notifyDatasetChanged is slow and has no animation, but list diffing is
chaotic and basically useless outside of search. However, clearing the
adapter and then populating it with new items seems to work quite well,
albeit with the scroll position being lost sadly. Switch to that.
---
 CHANGELOG.md                                  |  1 +
 .../auxio/music/excluded/ExcludedDialog.kt    | 31 +++++++++----------
 .../org/oxycblt/auxio/ui/RecyclerFramework.kt | 29 +++++++++++++++--
 3 files changed, 42 insertions(+), 19 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6004e65a4..aa2fd9356 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,7 @@
 
 #### What's New
 - Folders on external drives can now be excluded on Android Q+ [#134]
+- Added toggle for edge-to-edge mode [#149]
 
 #### What's Improved
 - Genre parsing now handles multiple integer values and cover/remix indicators (May wipe playback state)
diff --git a/app/src/main/java/org/oxycblt/auxio/music/excluded/ExcludedDialog.kt b/app/src/main/java/org/oxycblt/auxio/music/excluded/ExcludedDialog.kt
index a9442273c..c9a543230 100644
--- a/app/src/main/java/org/oxycblt/auxio/music/excluded/ExcludedDialog.kt
+++ b/app/src/main/java/org/oxycblt/auxio/music/excluded/ExcludedDialog.kt
@@ -86,17 +86,19 @@ class ExcludedDialog :
             }
         }
 
-        binding.excludedRecycler.adapter = excludedAdapter
-
-        if (savedInstanceState != null) {
-            val pendingDirs = savedInstanceState.getStringArrayList(KEY_PENDING_DIRS)
-            if (pendingDirs != null) {
-                updateDirectories(pendingDirs.mapNotNull(ExcludedDirectory::fromString))
-                return
-            }
+        binding.excludedRecycler.apply {
+            adapter = excludedAdapter
+            itemAnimator = null
         }
 
-        updateDirectories(settingsManager.excludedDirs)
+        val dirs =
+            savedInstanceState
+                ?.getStringArrayList(KEY_PENDING_DIRS)
+                ?.mapNotNull(ExcludedDirectory::fromString)
+                ?: settingsManager.excludedDirs
+
+        excludedAdapter.data.submitList(dirs)
+        requireBinding().excludedEmpty.isVisible = dirs.isEmpty()
     }
 
     override fun onSaveInstanceState(outState: Bundle) {
@@ -111,7 +113,8 @@ class ExcludedDialog :
     }
 
     override fun onRemoveDirectory(dir: ExcludedDirectory) {
-        updateDirectories(excludedAdapter.data.currentList.toMutableList().also { it.remove(dir) })
+        excludedAdapter.data.remove(dir)
+        requireBinding().excludedEmpty.isVisible = excludedAdapter.data.currentList.isEmpty()
     }
 
     private fun addDocTreePath(uri: Uri?) {
@@ -123,7 +126,8 @@ class ExcludedDialog :
 
         val dir = parseExcludedUri(uri)
         if (dir != null) {
-            updateDirectories(excludedAdapter.data.currentList.toMutableList().also { it.add(dir) })
+            excludedAdapter.data.add(dir)
+            requireBinding().excludedEmpty.isVisible = false
         } else {
             requireContext().showToast(R.string.err_bad_dir)
         }
@@ -142,11 +146,6 @@ class ExcludedDialog :
         return ExcludedDirectory.fromString(treeUri)
     }
 
-    private fun updateDirectories(dirs: List<ExcludedDirectory>) {
-        excludedAdapter.data.submitList(dirs)
-        requireBinding().excludedEmpty.isVisible = dirs.isEmpty()
-    }
-
     private fun saveAndRestart() {
         settingsManager.excludedDirs = excludedAdapter.data.currentList
 
diff --git a/app/src/main/java/org/oxycblt/auxio/ui/RecyclerFramework.kt b/app/src/main/java/org/oxycblt/auxio/ui/RecyclerFramework.kt
index 315802d87..fbfe17c4c 100644
--- a/app/src/main/java/org/oxycblt/auxio/ui/RecyclerFramework.kt
+++ b/app/src/main/java/org/oxycblt/auxio/ui/RecyclerFramework.kt
@@ -20,6 +20,7 @@ package org.oxycblt.auxio.ui
 import android.content.Context
 import android.view.View
 import android.view.ViewGroup
+import android.widget.Adapter
 import androidx.annotation.StringRes
 import androidx.recyclerview.widget.AsyncListDiffer
 import androidx.recyclerview.widget.DiffUtil
@@ -188,6 +189,7 @@ abstract class BackingData<T> {
  */
 class PrimitiveBackingData<T>(private val adapter: RecyclerView.Adapter<*>) : BackingData<T>() {
     private var _currentList = mutableListOf<T>()
+
     /** The current list backing this adapter. */
     val currentList: List<T>
         get() = _currentList
@@ -196,13 +198,34 @@ class PrimitiveBackingData<T>(private val adapter: RecyclerView.Adapter<*>) : Ba
     override fun getItemCount(): Int = _currentList.size
 
     /**
-     * Update the list with a [newList]. This calls [RecyclerView.Adapter.notifyDataSetChanged]
-     * internally, which is inefficient but also the most reliable update callback.
+     * Update the list with a [newList]. This does a basic animation that removes all items and
+     * replaces them with the new ones.
      */
     @Suppress("NotifyDatasetChanged")
     fun submitList(newList: List<T>) {
+        if (_currentList.isNotEmpty()) {
+            val oldListSize = _currentList.size
+            _currentList.clear()
+            adapter.notifyItemRangeRemoved(0, oldListSize)
+        }
+
         _currentList = newList.toMutableList()
-        adapter.notifyDataSetChanged()
+        adapter.notifyItemRangeInserted(0, _currentList.size)
+    }
+
+    /** Add an item to the list. */
+    fun add(item: T) {
+        _currentList.add(item)
+        adapter.notifyItemInserted(_currentList.lastIndex)
+    }
+
+    /** Remove an item from the list. */
+    fun remove(item: T) {
+        val idx = _currentList.indexOf(item)
+        if (idx != -1) {
+            _currentList.removeAt(idx)
+            adapter.notifyItemRemoved(idx)
+        }
     }
 }