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]')),
        ],
      ),

keyboardType: TextInputType。number会在焦点上打开一个num pad，当用户输入/经过任何其他内容时，我将清除文本字段。

keyboardType: TextInputType.number,
onChanged: (String newVal) {
    if(!isNumber(newVal)) {
        editingController.clear();
    }
}

// Function to validate the number
bool isNumber(String value) {
    if(value == null) {
        return true;
    }
    final n = num.tryParse(value);
    return n!= null;
}

如果需要使用双位数:

keyboardType: TextInputType.numberWithOptions(decimal: true),
inputFormatters: [FilteringTextInputFormatter.allow(RegExp('[0-9.,]')),],
onChanged: (value) => doubleVar = double.parse(value),

RegExp('[0-9.，]')允许0到9之间的数字，也允许逗号和点。

double.parse()将字符串转换为double。

别忘了你需要: 导入的包:颤振/ services.dart ';

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();
      },
    );
  }
}

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
          ),
        ],
      )),
    );
  }
}

对于数字输入或数字键盘，您可以使用keyboardType: TextInputType.number

TextFormField(
  decoration: InputDecoration(labelText:'Amount'),
    controller: TextEditingController(
  ),
  validator: (value) {
    if (value.isEmpty) {
      return 'Enter Amount';
    }
  },
  keyboardType: TextInputType.number
)