颤动中的 Tab 顺序

TienVD 发表于 Dev

天维达

在我的 Windows 应用程序上（界面如下所示：https : //i.stack.imgur.com/SibAC.png）

当我聚焦到 Input-1 并按下键盘上的 Tab 键时，主要焦点将聚焦到 Input-3。有什么办法可以重新安排我的焦点顺序：Input-1 -> Input-2 -> Input-3 -> Input-4 -> Input-5。

注意：这不是 flutter 文档示例中的 Tab bar/tab controller。

这是我的代码：

3个文件在同一个根目录下

main.dart

import 'package:flutter/material.dart';
import 'tab1.dart';
import 'tab2.dart';

void main() {
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Tab oder',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: const MyHomePage(title: 'Tab order'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  const MyHomePage({Key? key, required this.title}) : super(key: key);

  final String title;

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  final TextEditingController _controller = TextEditingController();
  final FocusNode _focusNode = FocusNode();

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Form(
        key: GlobalKey<FormState>(),
        onChanged: () {
          Form.of(primaryFocus!.context!)!.save();
        },
        child: Row(
          mainAxisAlignment: MainAxisAlignment.center,
          crossAxisAlignment: CrossAxisAlignment.end,
          children: [
            Container(
              constraints: const BoxConstraints.tightFor(width: 200.0, height: 200.0),
              child: TextFormField(
                controller: _controller,
                focusNode: _focusNode,
                decoration: const InputDecoration(
                  filled: true,
                  fillColor: Colors.yellow,
                ),
              ),
            ),
            const SizedBox(width: 150.0),
            Column(
              mainAxisAlignment: MainAxisAlignment.end,
              children: <Widget>[
                Container(
                  constraints: const BoxConstraints.tightFor(width: 200.0, height: 120.0),
                  child: Tab1(),
                ),
                Container(
                  constraints: const BoxConstraints.tightFor(width: 200.0, height: 120.0),
                  child: Tab2(),
                ),
              ],
            ),
          ],
        ),
      ),
    );
  }
}

tab1.dart

import 'package:flutter/material.dart';

class Tab1 extends StatefulWidget {
  @override
  _Tab1State createState() => _Tab1State();
}

class _Tab1State extends State<Tab1> {
  final TextEditingController _controller1 = TextEditingController();
  final TextEditingController _controller2 = TextEditingController();
  final FocusNode _focusNode1 = FocusNode();
  final FocusNode _focusNode2 = FocusNode();

  @override
  build(BuildContext context) {
    return Column(
      children: [
        TextFormField(
          controller: _controller1,
          focusNode: _focusNode1,
          decoration: const InputDecoration(
            filled: true,
            fillColor: Colors.greenAccent,
          ),
        ),
        TextFormField(
          controller: _controller2,
          focusNode: _focusNode2,
          decoration: const InputDecoration(
            filled: true,
            fillColor: Colors.greenAccent,
          ),
        ),
      ],
    );
  }
}

tab2.dart

import 'package:flutter/material.dart';

class Tab2 extends StatefulWidget {
  @override
  _Tab2State createState() => _Tab2State();
}

class _Tab2State extends State<Tab2> {
  final TextEditingController _controller1 = TextEditingController();
  final TextEditingController _controller2 = TextEditingController();
  final FocusNode _focusNode1 = FocusNode();
  final FocusNode _focusNode2 = FocusNode();

  @override
  build(BuildContext context) {
    return Column(
      children: [
        TextFormField(
          controller: _controller1,
          focusNode: _focusNode1,
          decoration: const InputDecoration(
            filled: true,
            fillColor: Colors.greenAccent,
          ),
        ),
        TextFormField(
          controller: _controller2,
          focusNode: _focusNode2,
          decoration: const InputDecoration(
            filled: true,
            fillColor: Colors.greenAccent,
          ),
        ),
      ],
    );
  }
}

croxx5f

您可以通过FocusTraversalGroup实现您想要的行为，使用此小部件可以指定您希望执行遍历的顺序。

这个小部件将遍历策略作为参数，我使用了OrderedTraversalPolicy，但还有其他类似的：

WidgetOrderTraversalPolicy，一种依赖于小部件创建顺序来描述遍历顺序的策略。

ReadingOrderTraversalPolicy，一种将订单描述为当前方向性的自然“阅读顺序”的策略。

NumericFocusOrder，分配数字遍历顺序的焦点顺序。

LexicalFocusOrder分配基于字符串的词法遍历顺序的焦点顺序。

还有一个关于构建自适应应用程序的非常有趣的部分，其中不同平台的焦点和遍历顺序是其中的一部分，您可以在此处查看

class Tab1 extends StatefulWidget {
  @override
  _Tab1State createState() => _Tab1State();
}

class _Tab1State extends State<Tab1> {
  final TextEditingController _controller1 = TextEditingController();
  final TextEditingController _controller2 = TextEditingController();
  final FocusNode _focusNode1 = FocusNode();
  final FocusNode _focusNode2 = FocusNode();

  @override
  build(BuildContext context) {
    return FocusTraversalGroup(
      policy: OrderedTraversalPolicy(),

如果您需要更改其他组（如 tab2）的遍历顺序，只需将它们包装在另一个组中FocusTraversalGroup并指定您希望它们遵循的策略。

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