你需要加一条线

keyboardType: TextInputType.phone,

在块“TextFormField”。在下面的例子:

TextField(
  controller: _controller,
  keyboardType: TextInputType.phone,
),

它应该是这样的:

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
          ),
        ],
      )),
    );
  }
}

这里是关于如何添加数字键盘，如何进行验证，如何添加样式，以及dart/flutter中的其他内容的所有细节。 我希望它能帮助你更好地学习。

Padding(
            padding: const EdgeInsets.all(3.0),
            child: TextFormField(
              maxLength: 10,
              keyboardType: TextInputType.number,
              validator: (value) {
                if (value.isEmpty) {
                  return 'Enter Number Please';
                }
                
                return null;
              },
              decoration: InputDecoration(
                prefixIcon: Icon(Icons.smartphone),
                prefixText: '+92',
                labelText: 'Enter Phone Number',
                contentPadding: EdgeInsets.zero,
                enabledBorder: OutlineInputBorder(),
                focusedBorder: OutlineInputBorder(
                    borderSide: BorderSide(
                      width: 2, color: Theme
                        .of(context)
                        .primaryColor,
                    )
                ),
                focusColor: Theme
                    .of(context)
                    .primaryColor,
              ),
            ),
          ),

TextField小部件需要设置keyboardType: 和inputFormatters: <TextInputFormatter>[FilteringTextInputFormatter。digitsOnly]只接受数字作为输入。

     TextField(
            keyboardType: TextInputType.number,
            inputFormatters: <TextInputFormatter>[
              FilteringTextInputFormatter.digitsOnly
            ], // Only numbers can be entered
          ),

在DartPad中的例子

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

    void main() => runApp(new MyApp());
    
    class MyApp extends StatelessWidget {
      @override
      Widget build(BuildContext context) {
        return MaterialApp(
          home: HomePage(),
          theme: ThemeData(primarySwatch: Colors.blue),
        );
      }
    }
    
    class HomePage extends StatefulWidget {
      @override
      State<StatefulWidget> createState() {
        return HomePageState();
      }
    }
    
    class HomePageState extends State<HomePage> {
      @override
      Widget build(BuildContext context) {
        return Scaffold(
          backgroundColor: Colors.white,
          body: Container(
              padding: const EdgeInsets.all(40.0),
              child: Column(
                mainAxisAlignment: MainAxisAlignment.center,
                children: <Widget>[
                  Text("This Input accepts Numbers only"),
                  SizedBox(height: 20),
                  TextField(
                    decoration: InputDecoration(
                      focusedBorder: OutlineInputBorder(
                        borderSide:
                            BorderSide(color: Colors.greenAccent, width: 5.0),
                      ),
                      enabledBorder: OutlineInputBorder(
                        borderSide: BorderSide(color: Colors.red, width: 5.0),
                      ),
                      hintText: 'Mobile Number',
                    ),
                    keyboardType: TextInputType.number,
                    inputFormatters: <TextInputFormatter>[
                      FilteringTextInputFormatter.digitsOnly
                    ], // Only numbers can be entered
                  ),
                  SizedBox(height: 20),
                  Text("You can test be Typing"),
                ],
              )),
        );
      }
    }

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

我需要en IntegerFormField与最小/最大的控制。最大的问题是当焦点改变时，oneditingcomplete没有被调用。以下是我的解决方案:

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

class IntegerFormField extends StatefulWidget {
  final int value, min, max;
  final InputDecoration decoration;
  final ValueChanged<TextEditingController> onEditingComplete;
  IntegerFormField({@required this.value, InputDecoration decoration, onEditingComplete, int min, int max})
      : min = min ?? 0,
        max = max ?? maxIntValue,
        onEditingComplete = onEditingComplete ?? ((_) {}),
        decoration = decoration ?? InputDecoration()
  ;

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

class _State extends State<IntegerFormField> {
  final TextEditingController controller = TextEditingController();

  @override
  void initState() {
    super.initState();
    controller.text = widget.value.toString();
  }

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

  void onEditingComplete() {
    {
      try {
        if (int.parse(controller.text) < widget.min)
          controller.text = widget.min.toString();
        else if (int.parse(controller.text) > widget.max)
          controller.text = widget.max.toString();
        else
          FocusScope.of(context).unfocus();
      } catch (e) {
        controller.text = widget.value.toString();
      }
      widget.onEditingComplete(controller);
    }
  }

  @override
  Widget build(BuildContext context) {
    return Focus(
      child: TextFormField(
        controller: controller,
        inputFormatters: [FilteringTextInputFormatter.digitsOnly],
        keyboardType: TextInputType.number,
        decoration: widget.decoration,
      ),
      onFocusChange: (value) {
        if (value)
          controller.selection = TextSelection(baseOffset: 0, extentOffset: controller.value.text.length);
        else
          onEditingComplete();
      },
    );
  }
}