只需将此添加到您的TextFormField

  keyboardType: TextInputType.number,
  inputFormatters: <TextInputFormatter>[
  FilteringTextInputFormatter.allow(RegExp(r'[0-9]')), ],

的例子,

TextFormField(
        controller: textController,
        onChanged: (value) {
         print(value);
        },
        keyboardType: TextInputType.number,
        inputFormatters: <TextInputFormatter>[
          FilteringTextInputFormatter.allow(RegExp(r'[0-9]')),
        ],
      ),

设置键盘和验证器

String numberValidator(String value) {
  if(value == null) {
    return null;
  }
  final n = num.tryParse(value);
  if(n == null) {
    return '"$value" is not a valid number';
  }
  return null;
}

new TextFormField(
    keyboardType: TextInputType.number, 
    validator: numberValidator, 
    textAlign: TextAlign.right
    ...

https://docs.flutter.io/flutter/material/TextFormField/TextFormField.html https://docs.flutter.io/flutter/services/TextInputType-class.html

你可以指定数字为keyboardType的TextField使用:

keyboardType: TextInputType.number

检查一下我的总管。飞镖文件

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

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    // TODO: implement build
    return new MaterialApp(
      home: new HomePage(),
      theme: new ThemeData(primarySwatch: Colors.blue),
    );
  }
}

class HomePage extends StatefulWidget {
  @override
  State<StatefulWidget> createState() {
    return new HomePageState();
  }
}

class HomePageState extends State<HomePage> {
  @override
  Widget build(BuildContext context) {
    return new Scaffold(
      backgroundColor: Colors.white,
      body: new Container(
          padding: const EdgeInsets.all(40.0),
          child: new Column(
        mainAxisAlignment: MainAxisAlignment.center,
        children: <Widget>[
          new TextField(
            decoration: new InputDecoration(labelText: "Enter your number"),
            keyboardType: TextInputType.number,
            inputFormatters: <TextInputFormatter>[
    FilteringTextInputFormatter.digitsOnly
], // Only numbers can be entered
          ),
        ],
      )),
    );
  }
}

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'),
            ),

设置你的keyboardType为TextInputType.number，

例如:keyboardType: TextInputType.number，

         TextFormField(
            controller: yourcontroller,
            keyboardType: TextInputType.number,
            decoration: const InputDecoration(
              labelText: 'Mobile',
              suffixIcon: Padding(
                padding: EdgeInsets.only(),
                child:
                Icon(Icons.phone_outlined, color: Color(0xffff4876)),
              ),
            ),
            validator: (text) {
              if (text == null || text.isEmpty) {
                return 'Please enter your Mobile No.';
              }
              return null;
            },
          ),

为避免粘贴的不是数字值，添加后

keyboardType: TextInputType.number

这段代码:

inputFormatters: [FilteringTextInputFormatter.digitsOnly] 

从https://api.flutter.dev/flutter/services/FilteringTextInputFormatter-class.html