单独小部件中的 Flutter Textfield onChanged: (value) {if (value.length == 2) focus.requestFocus(nextFocusNode);} 不起作用

Question

我尝试制作一个单独的 TextField 小部件以重复使用。因为有很多代码我会重复

，而且我想让光标在 onchanged 中有 2 个数字时跳转到下一个 TextField。所以我使用该值来查看是否已经输入了 2 个数字。我使用上下文来关注下一个焦点节点。

如果我将它放在同一个小部件中，但当我提取该小部件时，它会起作用。这是行不通的。

请你帮助我好吗？

是否可以？

import 'package:flutter/material.dart';
import 'package:careapp/widgets/layout/time_input.dart';

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

  @override
  _newInputState createState() => _newInputState();
}

class _newInputState extends State<newInput> {
  final hoursController = TextEditingController();
  final minutesController = TextEditingController();

  final nextFocusNode = FocusNode();

  @override
  void dispose() {
    hoursController.dispose();
    minutesController.dispose();
    nextFocusNode.dispose();
    super.dispose();
  }


  @override
  Widget build(BuildContext context) {
    final focus = FocusScope.of(context);
    return Scaffold(
      appBar: AppBar(
        title: Text('Add input'),
        actions: [
          IconButton(
            onPressed: _addEvent,
            icon: Icon(Icons.save),
          ),
        ],
      ),
      body: Card(
        elevation: 6,
        child: Container(
          padding: EdgeInsets.only(top: 15),
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              Container(
                //height: 100,
                padding: EdgeInsets.symmetric(
                  horizontal: 15,
                  vertical: 20,
                ),
                child: Row(
                  children: [
                    Container(
                      child: Text('Time:'),
                    ),
                    timeInput(
                      labelText: 'Hour',
                      onSubmitted: () {},
                      controller: hoursController,
                      onChanged: (value) {
                        if (value.length == 2)
                          focus.requestFocus(nextFocusNode);
                      },
                      //textInputAction: TextInputAction.next,
                      // onEditingComplete: () => focus.nextFocus(),
                    ),
                    Container(
                      child: Text(
                        ':',
                        style: TextStyle(
                          fontSize: 20,
                          //fontWeight: FontWeight.bold,
                        ),
                      ),
                    ),
                    timeInput(
                      labelText: 'Min',
                      onSubmitted: () {},
                      controller: minutesController,
                      focusNode: nextFocusNode,
                    ),
              Row(
                mainAxisAlignment: MainAxisAlignment.end,
                children: [
                  ElevatedButton(
                    onPressed: () {},
                    child: Text('Add Event'),
                  ),
                ],
              )
            ],
          ),
        ),
      ),
    );
  }
}

import 'package:flutter/material.dart';

class timeInput extends StatelessWidget {
  final String labelText;
  final VoidCallback onSubmitted;
  final Function? onChanged;
  final VoidCallback? onEditingComplete;
  FocusNode? focusNode;
  final TextInputAction textInputAction;
  final TextEditingController controller;
  // final String lastname;
  // final String birthday;
  // final String id;

  timeInput(
      {required this.labelText,
      required this.onSubmitted,
      this.focusNode,
      this.textInputAction = TextInputAction.done,
      this.onChanged,
      this.onEditingComplete = _onEditingComplete,
      required this.controller});

  static _onEditingComplete() {}

  @override
  Widget build(BuildContext context) {
    return Flexible(
      child: Container(
        padding: EdgeInsets.all(10),
        height: 50,
        width: 70,
        child: TextField(
          // onChanged: (_) => onChanged!(),
          onChanged: (_) => onChanged!(),
          textInputAction: textInputAction,
          // onEditingComplete: onEditingComplete,
          maxLength: 2,
          //style: ,
          decoration: InputDecoration(
            //labelText: 'Uur',
            labelText: labelText,
            border: OutlineInputBorder(),
            counterText: '',
          ),
          controller: controller,
          keyboardType: TextInputType.numberWithOptions(decimal: false),
          onSubmitted: (_) =>
              onSubmitted(), //You must add an input but underscore indicates that you are not using it
          // onChanged: (val) => amountInput = val,
        ),
      ),
    );
  }
}

Answer 1

请尝试这个

import 'package:flutter/material.dart';
import 'package:careapp/widgets/layout/time_input.dart';

const Color darkBlue = Color.fromARGB(255, 18, 32, 47);

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

  @override
  _newInputState createState() => _newInputState();
}

class _newInputState extends State<newInput> {
  final hoursController = TextEditingController();
  final minutesController = TextEditingController();

  final nextFocusNode = FocusNode();

  @override
  void dispose() {
    hoursController.dispose();
    minutesController.dispose();
    nextFocusNode.dispose();
    super.dispose();
  }


  @override
  Widget build(BuildContext context) {
    final focus = FocusScope.of(context);

    return Scaffold(
        appBar: AppBar(
          title: Text('Add input'),
          actions: [
            IconButton(
              onPressed: (){
              },
              icon: Icon(Icons.save),
            ),
          ],
        ),
        body: Card(
            elevation: 6,
            child: Container(
              padding: EdgeInsets.only(top: 15),
              child: Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: [
                    Container(
                      //height: 100,
                      padding: EdgeInsets.symmetric(
                        horizontal: 15,
                        vertical: 20,
                      ),
                      child: Row(
                        children: [
                          Container(
                            child: Text('Time:'),
                          ),
                          timeInput(
                            labelText: 'Hour',
                            onSubmitted: () {},
                            controller: hoursController,
                            onChanged: (v) {
                              if (v.length == 2){
                                print("ok");
                                FocusScope.of(context).nextFocus();
                              }
                              //focus.requestFocus(nextFocusNode);
                            },
                            //textInputAction: TextInputAction.next,
                          ),
                          Container(
                            child: Text(':',
                              style: TextStyle(
                                fontSize: 20,
                                //fontWeight: FontWeight.bold,
                              ),
                            ),
                          ),
                          timeInput(
                            labelText: 'Min',
                            onSubmitted: () {},
                            controller: minutesController,
                            focusNode: nextFocusNode,
                          ),
                          Row(
                            mainAxisAlignment: MainAxisAlignment.end,
                            children: [
                              ElevatedButton(
                                onPressed: () {},
                                child: Text('Add Event'),
                              ),
                            ],
                          )
                        ],
                      ),
                    ),
                  ]),
            )
        )
    );
  }
}

---

class timeInput extends StatelessWidget {
  final String labelText;
  final VoidCallback onSubmitted;
  final  Function? onChanged;
  final VoidCallback? onEditingComplete;
  FocusNode? focusNode;
  final TextInputAction textInputAction;
  final TextEditingController controller;
  // final String lastname;
  // final String birthday;
  // final String id;

  timeInput(
      {required this.labelText,
        required this.onSubmitted,
        this.focusNode,
        this.textInputAction = TextInputAction.done,
        this.onChanged,
        this.onEditingComplete = _onEditingComplete,
        required this.controller});

  static _onEditingComplete() {}


  @override
  Widget build(BuildContext context) {
    return Flexible(
      child: Container(
        padding: EdgeInsets.all(10),
        height: 50,
        width: 70,
        child: TextField(
          // onChanged: (_) => onChanged!(),
          onChanged: (v)=>onChanged!(v),
          textInputAction: textInputAction,
          // onEditingComplete: onEditingComplete,
          maxLength: 2,
          //style: ,
          decoration: InputDecoration(
            //labelText: 'Uur',
            labelText: labelText,
            border: OutlineInputBorder(),
            counterText: '',
          ),
          controller: controller,
          keyboardType: TextInputType.numberWithOptions(decimal: false),
          onSubmitted: (_) =>
              onSubmitted(), //You must add an input but underscore indicates that you are not using it
          // onChanged: (val) => amountInput = val,
        ),
      ),
    );
  }
}