flutter FloatingActionButton 设置圆形按钮

flutter FloatingActionButton 设置圆形按钮可以通过shape属性实现

FloatingActionButton(
            backgroundColor:_currentIndex==2?Colors.red:Colors.blue,
            shape: const CircleBorder(),   //设置形状
            child: const Icon(Icons.add), 
            onPressed: () {
              setState(() {
                _currentIndex=2;
              });
            }
        ),
      ),

完整代码如下：

import 'package:flutter/material.dart';
import './tabs/home.dart';
import './tabs/category.dart';
import './tabs/message.dart';
import './tabs/setting.dart';
import './tabs/user.dart';

class Tabs extends StatefulWidget {
  const Tabs({super.key});

  @override
  State<Tabs> createState() => _TabsState();
}

class _TabsState extends State<Tabs> {
  int _currentIndex = 0;
  final List<Widget> _pages = const [
    HomePage(),
    CategoryPage(),
    MessagePage(),
    SettingPage(),
    UserPage()
  ];
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text("Flutter App")),
      body: _pages[_currentIndex],
      bottomNavigationBar: BottomNavigationBar(
          fixedColor: Colors.red, //选中的颜色
          // iconSize:35,           //底部菜单大小
          currentIndex: _currentIndex, //第几个菜单选中
          type: BottomNavigationBarType.fixed, //如果底部有4个或者4个以上的菜单的时候就需要配置这个参数
          onTap: (index) {
            //点击菜单触发的方法
            //注意
            setState(() {
              _currentIndex = index;
            });
          },
          items: const [
            BottomNavigationBarItem(icon: Icon(Icons.home), label: "首页"),
            BottomNavigationBarItem(icon: Icon(Icons.category), label: "分类"),
            BottomNavigationBarItem(icon: Icon(Icons.message), label: "消息"),
            BottomNavigationBarItem(icon: Icon(Icons.settings), label: "设置"),
            BottomNavigationBarItem(icon: Icon(Icons.people), label: "用户")
          ]),
      floatingActionButton: Container(               
        height: 60,  //调整FloatingActionButton的大小
        width: 60,
        //圆形        
        padding: const EdgeInsets.all(5),
        margin: const EdgeInsets.only(top: 5),  //调整FloatingActionButton的位置
        decoration: BoxDecoration(
          color: Colors.white,
          borderRadius: BorderRadius.circular(30),
        ),
        child: FloatingActionButton(
            backgroundColor:_currentIndex==2?Colors.red:Colors.blue,
            shape: const CircleBorder(),   //设置形状
            child: const Icon(Icons.add), 
            onPressed: () {
              setState(() {
                _currentIndex=2;
              });
            }
        ),
      ),
      floatingActionButtonLocation:
          FloatingActionButtonLocation.centerDocked, //配置浮动按钮的位置
    );
  }
}