How to validate that a text field doesn't contain a whitespace in flutter? I'm trying to show it on a dialogue

if (_descriptionController2.text.isEmpty) { EasyLoading.showError('Please write a review!');

like this one but i don't know what should i write in the if statement.

CodePudding user response：

try validator work for me here is my code

validator: (value) {
                    if (value == null || value.isEmpty) {
                      return '*Required';
                    }
                    return null;
                  },

here is another one only letters

 validator: (value) {
                              if (value == null || value.isEmpty) {
                                return 'Please enter your first name';
                              } else if (!isAlpha(value)) {
                                return 'Only Letters Please';
                              }
                              return null;

CodePudding user response：

Add the following to check for whitespace

if (RegExp(r"\s").hasMatch(_descriptionController2.text)) {
      EasyLoading.showError('Text contains whitespace!')
    }