How to know when user delete the input in VerificationCodeInput Flutter

Question

I want to make a verification code input in my app. I'm using this widget to do that. But I don't know how to detect if the user delete the number that he/she inputted after he fully input in the widget so I can disable my submit button. I did the following. How can I know whether the user delete the number he/she inputted after he/she fully input in the field? Thanks!

VerificationCodeInput(
 keyboardType: TextInputType.number,
 length: 4,
 onCompleted: (String value) {
  setState(() {
   full = true;
  });
 },
),

Answer 1

You can go to the source https://github.com/tiny-express/flutter_verification_code_input and see in code developers made - logic that you want is not provided.

So, you have possibility to fork this package and implement what you need by yourself.

Just an example I made the fork https://github.com/awaik/flutter_verification_code where implemented one more check for editing.

It works like on attached screen.

For implementing it in your code you should change your pubspec.yaml with this new package

dependencies:
  flutter:
    sdk: flutter
  flutter_verification_code: ^0.1.4

And in code you can use it like this

  body: Column(
    children: <Widget>[
      Padding(
        padding: const EdgeInsets.all(8.0),
        child: Center(
          child: Text(
            'Enter your code',
            style: TextStyle(fontSize: 20.0),
          ),
        ),
      ),
      VerificationCodeInput(
        keyboardType: TextInputType.number,
        length: 4,
        autofocus: false,
        onCompleted: (String value) {
          print(value);
          setState(() {
            _code = value;
          });
        },
        onEditing: (bool value) {
          setState(() {
            _onEditing = value;
          });
        },
      ),
      (_onEditing != true)
          ? Padding(
              padding: const EdgeInsets.all(8.0),
              child: Center(
                child: Text(
                  'Your code: $_code',
                ),
              ),
            )
          : Container(
              child: Text(
                'Please enter full code',
              ),
            ),
    ],

Full example here https://pub.dev/packages/flutter_verification_code

(and of course great thanks for original developers)