BottomNavigationBarItem中添加的四个图标不起作用

Question

我不熟悉，尝试添加四个图标时创建了底部导航栏。图标颜色变为白色。任何人都可以建议我如何实现这一目标。下面是我的代码。任何帮助将不胜感激。

 bottomNavigationBar: new BottomNavigationBar(items: [
    new BottomNavigationBarItem(icon: new Icon(Icons.add), title: new Text("Text")),
    new BottomNavigationBarItem(icon: new Icon(Icons.person), title: new Text("Contact")),
    new BottomNavigationBarItem(icon: new Icon(Icons.accessibility), title: new Text("Acess")),
    new BottomNavigationBarItem(icon: new Icon(Icons.account_balance), title: new Text("Balance"))
  ]),

Answer 1

如果元素多于3个，则需要显式设置 type: BottomNavigationBarType.fixed,

bottomNavigationBar: new BottomNavigationBar(
    type: BottomNavigationBarType.fixed,
    items: [
    new BottomNavigationBarItem(icon: new Icon(Icons.add), title: new Text("Text")),
    new BottomNavigationBarItem(icon: new Icon(Icons.person), title: new Text("Contact")),
    new BottomNavigationBarItem(icon: new Icon(Icons.accessibility), title: new Text("Acess")),
    new BottomNavigationBarItem(icon: new Icon(Icons.account_balance), title: new Text("Balance"))
  ]),

如果提供了3个以上的BottomNavigationBar项目，则类型（如果未指定）将根据https://docs.flutter.io/flutter/material/BottomNavigationBar/BottomNavigationBar.html更改为BottomNavigationBarType.shifting 。