Flutter TextFormField：键盘出现，瞬间消失

Question

当我单击TextFormField 时，键盘出现，然后立即消失，就像闪烁一样。不知是不是因为少了一些参数？还是其他一些问题？谢谢。这是我的相关代码。

final _formKey = GlobalKey<FormState>();
String? _account;
Widget _showAccountInput() {
    return Padding(
      padding: const EdgeInsets.fromLTRB(15.0, 10.0, 0.0, 0.0),
      child: new TextFormField(
        maxLines: 1,
        obscureText: true,
        autofocus: false,
        style: TextStyle(fontSize: 15),
        decoration: new InputDecoration(
            border: InputBorder.none,
            hintText: 'input',
            icon: new Icon(
              Icons.lock,
              color: Colors.grey,
            )),
        onSaved: (value) => _account = value?.trim(),
      ),
    );
  }
  Widget build(BuildContext context) {
    // TODO: implement build
    return Scaffold(
      appBar: new AppBar(
        title: new Text("Second Screen"),
      ),
      body: Form(
        key: _formKey,
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: <Widget>[
            _showAccountInput()


          ],
        ),
      ),
    );
  }
}

Answer 1

如果您的构建方法在 StatelessWidget 中，请尝试将其更改为 StatefulWidget

Answer 2

我修改了你的一些代码，键盘工作正常。也许您可以尝试一下或与您的代码进行比较，以便找到原因。这是完整的代码

import 'package:flutter/material.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: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: const MyHomePage(),
    );
  }
}

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

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

class _MyHomePageState extends State<MyHomePage> {
  final _formKey = GlobalKey<FormState>();
  String? _account;
  Widget _showAccountInput() {
    return Padding(
      padding: const EdgeInsets.fromLTRB(15.0, 10.0, 0.0, 0.0),
      child: TextFormField(
        maxLines: 1,
        obscureText: true,
        autofocus: false,
        style: const TextStyle(fontSize: 15),
        decoration: const InputDecoration(
            border: InputBorder.none,
            hintText: 'input',
            icon: Icon(
              Icons.lock,
              color: Colors.grey,
            )),
        onSaved: (value) => _account = value?.trim(),
      ),
    );
  }

  // @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text("Second Screen"),
      ),
      body: Form(
        key: _formKey,
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: <Widget>[_showAccountInput()],
        ),
      ),
    );
  }
}

Answer 3

不需要使用有状态的小部件，因为小部件的状态不会改变。
完成该示例的最简单方法是先创建文本字段小部件，然后提取方法并使其成为可重用小部件。


class Test extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Column(
        crossAxisAlignment: CrossAxisAlignment.center,
        mainAxisAlignment: MainAxisAlignment.center,
        children: [ShowAccountInput()],
      ),
    );
  }
}

class ShowAccountInput extends StatelessWidget {
  String? account;

  ShowAccountInput({
    this.account,
    Key? key,
  }) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return Padding(
      padding: const EdgeInsets.fromLTRB(15.0, 10.0, 0.0, 0.0),
      child: TextFormField(
        maxLines: 1,
        obscureText: true,
        decoration: const InputDecoration(
            hintText: 'input',
            border: InputBorder.none,
            icon: Icon(
              Icons.lock,
              color: Colors.grey,
            )),
        onSaved: (value) => account = value?.trim(),
      ),
    );
  }
}

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