嘿，我试着给予你一个选择：

我没有使用图像或图标，而是将其更改为包含图标和文本的列的容器。也设置这个容器的背景颜色为红色以获得一个唯一的颜色为那个标签.然后设置一个空字符串到这个标签属性以隐藏那个项目的默认标签.

items: [
            BottomNavigationBarItem(
              activeIcon: ImageIcon(AssetImage("assets/images/home-icon.png"), size: 25,),
              label: "Home",
              icon: ImageIcon(AssetImage("assets/images/home-icon.png"), size: 25, color: Color(0xff909090),),
            ),
            BottomNavigationBarItem(
              icon: Container(
                width: 28,
                height: 28,
                child: Column(
                  mainAxisAlignment: MainAxisAlignment.center,
                  children: [
                    Icon(Icons.add, color: Colors.white, size: 20),
                    Text(
                      "Create",
                      style: TextStyle(fontSize: 8, color: Colors.white),
                    ),
                  ],
                ),
                decoration: BoxDecoration(
                  color: Colors.red,
                  borderRadius: BorderRadius.circular(5),
                ),
              ),
              label: "", // Set empty label to hide the default label
            ),
            BottomNavigationBarItem(
              activeIcon: ImageIcon(AssetImage("assets/images/ticket-icon.png"), size: 25, color: Color(0xff3D3D3D),),
              label: "Reminder",
              icon: ImageIcon(AssetImage("assets/images/ticket-icon.png"), size: 25, color: Color(0xff909090),),
            ),
          ],
        ),

您可以尝试使用BottomNavigationBar的selected和unselected color属性：

import 'package:flutter/material.dart'; import 'package:playticket/screens/01.dart';

class CustomNavBar extends StatefulWidget {   CustomNavBar({Key? key}) : super(key: key);

  @override   State<CustomNavBar> createState() =>
_CustomNavBarState(); }

class _CustomNavBarState extends State<CustomNavBar> {   int
_currentIndex = 0;

  @override   Widget build(BuildContext context) {
    List<Widget> _screens = [
     Screen1(),
     Screen1(),
     Screen1(),
    ];
    return Scaffold(
      body: _screens[_currentIndex],
      bottomNavigationBar: SizedBox(
        height: 90,
        child: BottomNavigationBar(

          backgroundColor: Colors.white,
          type: BottomNavigationBarType.fixed,
          selectedLabelStyle: TextStyle(fontSize: 12, fontFamily: "Poppins", fontWeight: FontWeight.w600),
          unselectedLabelStyle: TextStyle(fontSize: 12, fontFamily: "Poppins", fontWeight: FontWeight.w600),
          unselectedItemColor: _currentIndex != 1 ? Color(0xff909090) : Colors.red,
          currentIndex: _currentIndex,
          selectedItemColor: _currentIndex != 1 ? Color(0xff3D3D3D) : Colors.red,
          onTap: (value) {
            setState(() => _currentIndex = value);
          },
          items: [
            BottomNavigationBarItem(
              activeIcon: ImageIcon(AssetImage("assets/images/home-icon.png"), size: 25,),
              label: "Home",
              icon: ImageIcon(AssetImage("assets/images/home-icon.png"), size: 25, color: Color(0xff909090),),
            ),
            BottomNavigationBarItem(
                icon: Image.asset("assets/images/add-box-fill.png", width: 28, height: 28, color: Colors.red),
                label: "Create",
               ),
            BottomNavigationBarItem(
                activeIcon: ImageIcon(AssetImage("assets/images/ticket-icon.png"), size: 25, color: Color(0xff3D3D3D),),
                label: "Reminder",
                icon: ImageIcon(AssetImage("assets/images/ticket-icon.png"), size: 25, color: Color(0xff909090),)
            ),
          ],
        ),
      ),
    );   } }