Merge branch 'master' into update_readme

README-ZH.md

 ## 使用要求
 
 #### Unity
+
 安装 **Unity 2018.4.10f1(LTS)** 或 **Unity 2019.1.14f1** 及其更高版本。 你可以从[https://unity3d.com/get-unity/download](https://unity3d.com/get-unity/download)下载最新的Unity。
 
 #### UIWidgets包

README.md

 ## Requirements
 
 #### Unity
+
 Install **Unity 2018.4.10f1 (LTS)** or **Unity 2019.1.14f1** and above. You can download the latest Unity on https://unity3d.com/get-unity/download.
 
 #### UIWidgets Package

Runtime/material/bottom_navigation_bar.cs

                     child: text
                 );
             }
-            else if (this.showUnselectedLabels) {
+            else if (!this.showUnselectedLabels) {
                 text = new FadeTransition(
                     opacity: this.animation,
                     child: text
             Color backgroundColor = null;
             switch (this.widget.type) {
                 case BottomNavigationBarType.fix:
+                    backgroundColor = this.widget.backgroundColor;
                     break;
                 case BottomNavigationBarType.shifting:
                     backgroundColor = this._backgroundColor;