From bbc6067a8fd27975418eb71f271fc9021ee1c2be Mon Sep 17 00:00:00 2001
From: kunfei <gekunfei@live.com>
Date: Sun, 26 Jan 2020 11:28:36 +0800
Subject: [PATCH] up

---
 .../ui/main/bookshelf/GroupManageDialog.kt    | 38 ++++++++++++++++---
 1 file changed, 33 insertions(+), 5 deletions(-)

diff --git a/app/src/main/java/io/legado/app/ui/main/bookshelf/GroupManageDialog.kt b/app/src/main/java/io/legado/app/ui/main/bookshelf/GroupManageDialog.kt
index 0d432e437..1022f4ed9 100644
--- a/app/src/main/java/io/legado/app/ui/main/bookshelf/GroupManageDialog.kt
+++ b/app/src/main/java/io/legado/app/ui/main/bookshelf/GroupManageDialog.kt
@@ -12,10 +12,7 @@ import android.widget.EditText
 import androidx.appcompat.widget.Toolbar
 import androidx.fragment.app.DialogFragment
 import androidx.lifecycle.Observer
-import androidx.recyclerview.widget.DividerItemDecoration
-import androidx.recyclerview.widget.ItemTouchHelper
-import androidx.recyclerview.widget.LinearLayoutManager
-import androidx.recyclerview.widget.RecyclerView
+import androidx.recyclerview.widget.*
 import io.legado.app.App
 import io.legado.app.R
 import io.legado.app.base.adapter.ItemViewHolder
@@ -79,7 +76,10 @@ class GroupManageDialog : DialogFragment(), Toolbar.OnMenuItemClickListener {
         )
         recycler_view.adapter = adapter
         App.db.bookGroupDao().liveDataAll().observe(viewLifecycleOwner, Observer {
-            adapter.setItems(it)
+            val diffResult =
+                DiffUtil.calculateDiff(GroupDiffCallBack(adapter.getItems(), it))
+            adapter.setItems(it, false)
+            diffResult.dispatchUpdatesTo(adapter)
         })
         val itemTouchCallback = ItemTouchCallback()
         itemTouchCallback.onItemTouchCallbackListener = adapter
@@ -145,6 +145,34 @@ class GroupManageDialog : DialogFragment(), Toolbar.OnMenuItemClickListener {
         }.show().applyTint().requestInputMethod()
     }
 
+    private class GroupDiffCallBack(
+        private val oldItems: List<BookGroup>,
+        private val newItems: List<BookGroup>
+    ) :
+        DiffUtil.Callback() {
+        override fun areItemsTheSame(oldItemPosition: Int, newItemPosition: Int): Boolean {
+            val oldItem = oldItems[oldItemPosition]
+            val newItem = newItems[newItemPosition]
+            return oldItem.groupId == newItem.groupId
+        }
+
+        override fun getOldListSize(): Int {
+            return oldItems.size
+        }
+
+        override fun getNewListSize(): Int {
+            return newItems.size
+        }
+
+        override fun areContentsTheSame(oldItemPosition: Int, newItemPosition: Int): Boolean {
+            val oldItem = oldItems[oldItemPosition]
+            val newItem = newItems[newItemPosition]
+            return oldItem.groupName == newItem.groupName
+                    && oldItem.order == newItem.order
+        }
+
+    }
+
     private inner class GroupAdapter(context: Context) :
         SimpleRecyclerAdapter<BookGroup>(context, R.layout.item_group_manage),
         ItemTouchCallback.OnItemTouchCallbackListener {