min static method

FormFieldValidator<String> min(double min, String errorMessage)

Validator that requires the field's value to be greater than or equal to the provided number.

Validate against a minimum of 5

          TextFormField(
           keyboardType: TextInputType.numberWithOptions(
             decimal: true,
             signed: true,
           ),
           decoration: InputDecoration(
             labelText: 'Minimum 5',
           ),
           validator: Validators.min(5, 'Value less than 5 not allowed'),
         ),

Implementation

static FormFieldValidator<String> min(double min, String errorMessage) {
  return (value) {
    if (value == null) {
      value = '';
    }
    if (value.trim().isEmpty)
      return null;
    else {
      final dValue = _toDouble(value);
      if (dValue < min)
        return errorMessage;
      else
        return null;
    }
  };
}