"Flutter TextFormField：键盘出现又瞬间消失"

Question

当我单击 TextFormField 时，键盘出现，然后它立即消失，就像闪烁一样。 我想知道是否是因为缺少一些参数？ 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<\/strong>中，请尝试将其更改为StatefulWidget<\/strong>

"

Answer 2

我修改了一些代码，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

1. 无需使用 statefull 小部件，因为小部件的状态没有改变。<\/li>
2. 执行该示例的最简单方法是首先创建文本字段小部件，然后提取该方法并使其可重用小部件。<\/li><\/ol>

    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(), ), ); } }<\/code><\/pre>"