我希望用户能够在我的颤振网络应用程序中使用"Tab"在控件之间跳转。我按照这篇文章抓住了"Tab"键并导航到下一个控件。
当用户按"Tab"时,光标会跳转到下一个文本框,但随后,当用户键入时,文本框中不显示任何字母。
可能出了什么问题?
这是代码:
class _LoginScreenState extends State<LoginScreen> {
FocusNode _passwordFocus;
FocusNode _emailFocus;
@override
void initState() {
super.initState();
_emailFocus = FocusNode();
_passwordFocus = FocusNode();
}
@override
void dispose() {
_emailFocus.dispose();
_passwordFocus.dispose();
super.dispose();
}
@override
Widget build(BuildContext context) {
final TextEditingController emailController =
new TextEditingController(text: this._email);
final TextEditingController passwordController =
new TextEditingController();
return Scaffold(
appBar: AppBar(
title: Text('Sign In'),
),
body: Column(
children: <Widget>[
RawKeyboardListener(
child: TextField(
autofocus: true,
controller: emailController,
decoration: InputDecoration(
labelText: "EMail",
),
),
onKey: (dynamic key) {
if (key.data.keyCode == 9) {
FocusScope.of(context).requestFocus(_passwordFocus);
}
},
focusNode: _emailFocus,
),
TextField(
controller: passwordController,
obscureText: true,
focusNode: _passwordFocus,
decoration: InputDecoration(
labelText: "Password",
),
),
],
),
);
}
}
事实证明,浏览器正在将焦点转移到其他地方。我在方法"build"中添加了对默认浏览器行为的预防:
import 'dart:html';
...
@override
Widget build(BuildContext context) {
document.addEventListener('keydown', (dynamic event) {
if (event.code == 'Tab') {
event.preventDefault();
}
});
...
对我有用的解决方案有点不同。我在颤振 2.0.1 与 Dart 2.12.0 上
import 'dart:html';
import 'package:flutter/foundation.dart';
...
@override
Widget build(BuildContext context) {
if (kIsWeb) {
document.addEventListener('keydown',
(event) => {if (event.type == 'tab') event.preventDefault()});
}
...
}
...