正如消息已经指出的那样,'title'属性已被弃用,已被'replace with 'label''所取代。
关于所选颜色未更改,您需要添加一个函数调用'onItemTapped'来通过设置状态来更改颜色。
以下是可工作的代码:
import 'package:flutter/material.dart';
void main() => runApp(const MyApp());
class MyApp extends StatelessWidget {
const MyApp({Key key}) : super(key: key);
static const String _title = 'TEST';
@override
Widget build(BuildContext context) {
return const MaterialApp(
title: _title,
home: MyStatefulWidget(),
);
}
}
class MyStatefulWidget extends StatefulWidget {
const MyStatefulWidget({Key key}) : super(key: key);
@override
_MyStatefulWidgetState createState() => _MyStatefulWidgetState();
}
class _MyStatefulWidgetState extends State<MyStatefulWidget> {
int _selectedIndex = 0;
static const TextStyle optionStyle =
TextStyle(fontSize: 30, fontWeight: FontWeight.bold);
static const List<Widget> _widgetOptions = <Widget>[
Text(
'Index 0: First',
style: optionStyle,
),
Text(
'Index 1: Second',
style: optionStyle,
),
];
void _onItemTapped(int index) {
setState(() {
_selectedIndex = index;
});
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: const Text('BottomNavigationBar'),
),
body: Center(
child: _widgetOptions.elementAt(_selectedIndex),
),
bottomNavigationBar: BottomNavigationBar(
items: const <BottomNavigationBarItem>[
BottomNavigationBarItem(
icon: Icon(Icons.home),
label: 'First',
),
BottomNavigationBarItem(
icon: Icon(Icons.exit_to_app),
label: 'Second',
),
],
selectedLabelStyle: TextStyle(fontSize: 22),
selectedItemColor: Colors.red,
onTap: _onItemTapped,
currentIndex: _selectedIndex),
);
}
}
selectedItemColor
部分的原因,因为Flutter可能存在一个bug。(https://github.com/flutter/flutter/issues/67897) - Robert SandbergselectedItemColor: some == expression? Colors.red : Colors.blue
。 - Robert Sandberg