CODEWITHSUNDEEP
regexflutterdartregex-group
Dhaval Kansara
Dhaval Kansara

Reputation: 3884

Regex for Decimal number not working in flutter TextFormField inputFormatters

The requirement for Regex:

I have tried to generate regex for the same on RegExr and it satisfied my requirements but when I applied the same for the flutter form TextFormField it not working.

Regex: ^[[0-9]{0,8}(\.[0-9]{1,4})?$|^[[0-9]{0,9}(\.[0-9]{1,3})?$|^[[0-9]{0,10}(\.[0-9]{1,2})?$|^[[0-9]{0,11}(\.[0-9]{1})?$|^[0-9]{0,12}

Flutter TextFieldCode: 

TextFormField(
   controller: _textEditingController,
   keyboardType:TextInputType.numberWithOptions(decimal: true),
   inputFormatters: <TextInputFormatter>[
          WhitelistingTextInputFormatter(RegExp(r'^[[0-9]{0,8}(\.[0-9]{1,4})?$|^[[0-9]{0,9}(\.[0-9]{1,3})?$|^[[0-9]{0,10}(\.[0-9]{1,2})?$|^[[0-9]{0,11}(\.[0-9]{1})?$|^[0-9]{0,12}')),
   ],
),

Using the above code I am not able to type dot(.) inside the TextFormField.

Note: Users should not be able to enter the number more than one decimal point in the TextFormField.

Upvotes: 2

Views: 6433

Answers (2)

Ajith
Ajith

Reputation: 393

Worked for me!

inputFormaters:[FilteringTextInputFormater.allow(RegEx("[0-9.]"))]

Upvotes: 1

Wiktor Stribiżew
Wiktor Stribiżew

Reputation: 626738

Note that if you want to validate the whole input sequence you need to define a validator: validateMyInput and then implement the function:

String validateMyInput(String value) {
    RegExp regex = new RegExp(r'^(?=\D*(?:\d\D*){1,12}$)\d+(?:\.\d{1,4})?$');
    if (!regex.hasMatch(value))
      return 'Enter Valid Number';
    else
      return null;
  }

See more details at Form Validation in Flutter.

The regex is 

^(?=\D*(?:\d\D*){1,12}$)\d+(?:\.\d{1,4})?$

See its demo. Details

  • ^ - start of string
  • (?=\D*(?:\d\D*){1,12}$) - one to twelve digits required in the string
  • \d+ - 1 or more digits
  • (?:\.\d{1,4})? - an optional sequence of a . and then 1, 2, 3 or 4 digits
  • $ - end of string.

Upvotes: 6

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