fixed #579

twidere/src/main/res/drawable/abc_dialog_material_background_dark.xml

@@ -0,0 +1,26 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright (C) 2016 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+-->
+
+<inset xmlns:android="http://schemas.android.com/apk/res/android"
+       android:insetBottom="16dp"
+       android:insetLeft="16dp"
+       android:insetRight="16dp"
+       android:insetTop="16dp">
+    <shape android:shape="rectangle">
+        <corners android:radius="2dp"/>
+        <solid android:color="#444444"/>
+    </shape>
+</inset>

twidere/src/main/res/values/themes.xml

@@ -64,6 +64,9 @@
 
     <style name="Theme.Twidere.Dialog" parent="Theme.AppCompat.Dialog">
 
+        <!-- TODO this is a simple fix for https://github.com/TwidereProject/Twidere-Android/issues/579 -->
+        <item name="android:windowBackground">@drawable/abc_dialog_material_background_dark</item>
+
         <!-- Widget styles -->
         <item name="android:listSeparatorTextViewStyle">@style/Widget.Dark.TextView.ListSeparator
         </item>