How to make sure that my text field doesn't have only numbers, it should have letters in flutte-CodePudding

how to validate that my text fields has characters [a-z]?

TextFormField(
                    maxLines: 20,
                    maxLength: 200,
                    controller: _descriptionController2,
                    decoration: InputDecoration(
                      contentPadding:
                          EdgeInsets.only(left: 10.0, top: 16.0),
                      hintText: "What do you think about the place?",
                      border: OutlineInputBorder(
                          borderRadius: BorderRadius.circular(16.0)),
                    ),
                  ),

CodePudding user response：

You can use regex on TextFormField validator:

TextFormField(
    validator: (value) {
      final RegExp regex = RegExp('[a-zA-Z]');
      if (value == null || value.isEmpty || !regex.hasMatch(value)) {
        return 'Must have letters';
      }    
      return null;
    },
),

This regex will check if have at least one letter on your string.

CodePudding user response：

    TextFormField(
                        maxLines: 20,
                        maxLength: 200,
                        controller: _descriptionController2,
    valdator: (value) {
    RegExp regEx = RegExp(r'^[A-Za-z0-9_.] $');
    
                                  if(!regEx.hasMatch(value)){
return "Must have alphabets"
    }

                                  if (value!.isEmpty) {
                                    return "Field cannot be empty";
                                  }
                                  
                                },
                        decoration: InputDecoration(
                          contentPadding:
                              EdgeInsets.only(left: 10.0, top: 16.0),
                          hintText: "What do you think about the place?",
                          border: OutlineInputBorder(
                              borderRadius: BorderRadius.circular(16.0)),
                        ),
                      ),