Flutter BottomNavigationBar

class BottomPage extends StatefulWidget{
  @override
  State<StatefulWidget> createState() =>_BottomPage();

}
class _BottomPage extends State<BottomPage>{
  var pageList=[HomePage(),NullPage(),NullPage(),PersonPage()];//要显示的内容
  int currentIndex=3;


  @override
  Widget build(BuildContext context) {
    // TODO: implement build
  return Scaffold(bottomNavigationBar: BottomNavigationBar(items: [
                                                      //bottomNavigationBar的图标
    BottomNavigationBarItem(icon: Icon(Icons.home),label: "房屋"),
    BottomNavigationBarItem(icon: Icon(Icons.movie),label: "场景"),
    BottomNavigationBarItem(icon: Icon(Icons.message),label: "消息"),
    BottomNavigationBarItem(icon: Icon(Icons.person),label: "我的")

  ],
  type: BottomNavigationBarType.fixed,//bottomNavigationBar的显示模式
    currentIndex: currentIndex,//初始按钮选择位置
    onTap: (index){index是点击对应按钮返回的索引值
    currentIndex=index;//自定义的currentIndex获取index的值
    setState(() {

    });
    },

  ),
  body: IndexedStack(index: currentIndex,//初始显示的内容位置
    children: pageList,),//添加内容的集合
  );


  }


}