下面是Android上实际的手机键盘代码:

按键部分:keyboardType: TextInputType.phone，

  TextFormField(
    style: TextStyle(
      fontSize: 24
    ),
    controller: _phoneNumberController,
    keyboardType: TextInputType.phone,
    decoration: InputDecoration(
      prefixText: "+1 ",
      labelText: 'Phone number'),
    validator: (String value) {
      if (value.isEmpty) {
        return 'Phone number (+x xxx-xxx-xxxx)';
      }
      return null;
    },
  ),

对于那些正在寻找使TextField或TextFormField只接受数字作为输入的人，尝试以下代码块:

用于flutter 1.20或更新版本

TextFormField(
  controller: _controller,
  keyboardType: TextInputType.number,
  inputFormatters: <TextInputFormatter>[
   // for below version 2 use this
 FilteringTextInputFormatter.allow(RegExp(r'[0-9]')), 
// for version 2 and greater youcan also use this
 FilteringTextInputFormatter.digitsOnly

  ],
  decoration: InputDecoration(
    labelText: "whatever you want",
    hintText: "whatever you want",
    icon: Icon(Icons.phone_iphone)
  )
)

对于1.20的早期版本

TextFormField(
    controller: _controller,
    keyboardType: TextInputType.number,
    inputFormatters: <TextInputFormatter>[
        WhitelistingTextInputFormatter.digitsOnly
    ],
    decoration: InputDecoration(
        labelText:"whatever you want", 
        hintText: "whatever you want",
        icon: Icon(Icons.phone_iphone)
    )
)

以下是Flutter中实际手机键盘的代码:

     //Mobile
            const TextField(
              keyboardType: TextInputType.number,
              decoration: InputDecoration(
                  prefixIcon: Icon(Icons.phone), hintText: 'Mobile'),
            ),

下面是Android上实际的手机键盘代码:

按键部分:keyboardType: TextInputType.phone，

  TextFormField(
    style: TextStyle(
      fontSize: 24
    ),
    controller: _phoneNumberController,
    keyboardType: TextInputType.phone,
    decoration: InputDecoration(
      prefixText: "+1 ",
      labelText: 'Phone number'),
    validator: (String value) {
      if (value.isEmpty) {
        return 'Phone number (+x xxx-xxx-xxxx)';
      }
      return null;
    },
  ),

U可以安装intl_phone_number_input包

dependencies:
  intl_phone_number_input: ^0.5.2+2

试试下面的代码:

import 'package:flutter/material.dart';
import 'package:intl_phone_number_input/intl_phone_number_input.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    var darkTheme = ThemeData.dark().copyWith(primaryColor: Colors.blue);

    return MaterialApp(
      title: 'Demo',
      themeMode: ThemeMode.dark,
      darkTheme: darkTheme,
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: Scaffold(
        appBar: AppBar(title: Text('Demo')),
        body: MyHomePage(),
      ),
    );
  }
}

class MyHomePage extends StatefulWidget {
  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  final GlobalKey<FormState> formKey = GlobalKey<FormState>();

  final TextEditingController controller = TextEditingController();
  String initialCountry = 'NG';
  PhoneNumber number = PhoneNumber(isoCode: 'NG');

  @override
  Widget build(BuildContext context) {
    return Form(
      key: formKey,
      child: Container(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            InternationalPhoneNumberInput(
              onInputChanged: (PhoneNumber number) {
                print(number.phoneNumber);
              },
              onInputValidated: (bool value) {
                print(value);
              },
              selectorConfig: SelectorConfig(
                selectorType: PhoneInputSelectorType.BOTTOM_SHEET,
                backgroundColor: Colors.black,
              ),
              ignoreBlank: false,
              autoValidateMode: AutovalidateMode.disabled,
              selectorTextStyle: TextStyle(color: Colors.black),
              initialValue: number,
              textFieldController: controller,
              inputBorder: OutlineInputBorder(),
            ),
            RaisedButton(
              onPressed: () {
                formKey.currentState.validate();
              },
              child: Text('Validate'),
            ),
            RaisedButton(
              onPressed: () {
                getPhoneNumber('+15417543010');
              },
              child: Text('Update'),
            ),
          ],
        ),
      ),
    );
  }

  void getPhoneNumber(String phoneNumber) async {
    PhoneNumber number =
        await PhoneNumber.getRegionInfoFromPhoneNumber(phoneNumber, 'US');

    setState(() {
      this.number = number;
    });
  }

  @override
  void dispose() {
    controller?.dispose();
    super.dispose();
  }
}

通过这个选项，你可以严格限制另一个字符的数字。

 inputFormatters: [WhitelistingTextInputFormatter.digitsOnly],
 keyboardType: TextInputType.number,

使用上述选项，您必须导入此

import 'package:flutter/services.dart';

使用这种选项，用户不能在文本框中粘贴字符