How to create number input field in Flutter?

Question

I'm unable to find a way to create an input field in Flutter that would open up a numeric keyboard and should take numeric input only. Is this possible with Flutter material widgets? Some GitHub discussions seem to indicate this is a supported feature but I'm unable to find any documentation about it.

Answer 1

You can specify the number as keyboardType for the TextField using:

keyboardType: TextInputType.number

Check my main.dart file

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
          ),
        ],
      )),
    );
  }
}

Answer 2

For those who are looking for making TextField or TextFormField accept only numbers as input, try this code block :

for flutter 1.20 or newer versions

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)
  )
)

for earlier versions of 1.20

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)
    )
)

Answer 3

Through this option you can strictly restricted another char with out number.

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

For using above option you have to import this

import 'package:flutter/services.dart';

using this kind of option user can not paste char in a textfield

Answer 4

Set the keyboard and a validator

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

Answer 5

For those who need to work with money format in the text fields:

To use only: , (comma) and . (period)

and block the symbol: - (hyphen, minus or dash)

as well as the: ⌴ (blank space)

In your TextField, just set the following code:

keyboardType: TextInputType.numberWithOptions(decimal: true),
inputFormatters: [BlacklistingTextInputFormatter(new RegExp('[\\-|\\ ]'))],

The simbols hyphen and space will still appear in the keyboard, but will become blocked.

Answer 6

To avoid paste not digit value, add after

keyboardType: TextInputType.number,

this code :

inputFormatters: [FilteringTextInputFormatter.digitsOnly] 

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

Answer 7

If you need to use a double number:

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

RegExp('[0-9.,]') allows for digits between 0 and 9, also comma and dot.

double.parse() converts from string to double.

Don't forget you need: import 'package:flutter/services.dart';

Answer 8

The TextField widget is required to set keyboardType: TextInputType.number, and inputFormatters: <TextInputFormatter>[FilteringTextInputFormatter.digitsOnly] to accept numbers only as input.

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

Example in DartPad

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"),
                ],
              )),
        );
      }
    }

Answer 9

You can use this two attributes together with TextFormField

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

It's allow to put only numbers, no thing else ..

https://api.flutter.dev/flutter/services/TextInputFormatter-class.html

Answer 10

As the accepted answer states, specifying keyboardType triggers a numeric keyboard:

keyboardType: TextInputType.number

Other good answers have pointed out that a simple regex-based formatter can be used to allow only whole numbers to be typed:

inputFormatters: [
  FilteringTextInputFormatter.allow(RegExp(r'[0-9]')),
],

The problem with this is that the regex only matches one symbol at a time, so limiting the number of decimal points (e.g.) cannot be achieved this way.

Also, others have also shown that if one wants validation for a decimal number, it can be achieved by using a TextFormField and it's validator parameter:

new TextFormField(
    keyboardType: TextInputType.number, 
    validator: (v) => num.tryParse(v) == null ? "invalid number" : null, 
    ...

The problem with this is that it cannot be achieved interactively, but only at form submission time.

---

I wanted to allow only decimal numbers to be typed, rather than validated later. My solution is to write a custom formatter leveraging int.tryParse:

/// Allows only decimal numbers to be input.
class DecimalNumberFormatter extends TextInputFormatter {
  @override
  TextEditingValue formatEditUpdate(
      TextEditingValue oldValue, TextEditingValue newValue) {
    // Allow empty input and delegate formatting decision to `num.tryParse`.
    return newValue.text != '' && num.tryParse(newValue.text) == null
        ? oldValue
        : newValue;
  }
}

Alternatively, one can use a regex for the custom formatter, which would apply to the whole input, not just a single symbol:

/// Allows only decimal numbers to be input. Limits decimal plates to 3.
class DecimalNumberFormatter extends TextInputFormatter {
  @override
  TextEditingValue formatEditUpdate(
      TextEditingValue oldValue, TextEditingValue newValue) {
    // Allow empty input.
    if (newValue.text == '') return newValue;

    // Regex: can start with zero or more digits, maybe followed by a decimal
    // point, followed by zero, one, two, or three digits.
    return RegExp('^\\d*\\.?\\d?\\d?\\d?\$').hasMatch(newValue.text)
        ? newValue
        : oldValue;
  }
}

This way, I can also limit the number of decimal plates to 3.

Answer 11

Number type only

keyboardType: TextInputType.number

And more option with number pad

keyboardType: TextInputType.numberWithOptions(decimal: true,signed: false)

Answer 12

You can try this:

TextFormField(
     keyboardType: TextInputType.number,
     decoration: InputDecoration(
              prefixIcon: Text("Enter your number: ")
     ),
     initialValue: "5",
     onSaved: (input) => _value = num.tryParse(input),
),

Answer 13

Here is code for actual Phone keyboard on Android:

Key part: 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;
    },
  ),

Answer 14

For number input or numeric keyboard you can use keyboardType: TextInputType.number

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

Answer 15

You can add input format with keyboard type, like this

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

Answer 16

You can Easily change the Input Type using the keyboardType Parameter and you have a lot of possibilities check the documentation TextInputType so you can use the number or phone value

 new TextField(keyboardType: TextInputType.number)

Answer 17

keyboardType: TextInputType.number would open a num pad on focus, I would clear the text field when the user enters/past anything else.

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;
}

Answer 18

Set your keyboardType to TextInputType.number,

Eg: 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;
            },
          ),

Answer 19

Just add this to your TextFormField

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

Example,

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