How to disable a button in flutter untill all Text feilds are filled

I have a registration form with multiple text feilds and a Radio button and a birthdate picker. I want to disable the submit button untill the user key in all the required feilds. I managed to do something but it only validates one text feild.

 bool activateTheButton =false;

@override
 initState(){
   super.initState();
    nameController = TextEditingController();

    nameController.addListener(() {
      final activateTheButton = nameController.text.isNotEmpty;
      setState(() => this.activateTheButton = activateTheButton);

   ......................
ElevatedButton( onPressed: activateTheButton
             ? (){

         }: null,

 }

How can I make it so that all the textfeilds along with the radio button and date of birth must have data first then activate button?

your help is highly appreciated.

Have a variable that enables/disables the button:

bool _disabled = true;

Use IgnorePointer and Opacity for the button:

IgnorePointer(
  ignoring: _disabled;
  child: Opacity(
    opacity: _disabled ? 0.5 : 1.0,
    child: YourButton(...),
  )
)

You are going to have controllers for each TextFields;

TextEditingController _controllerOne;
TextEditingController _controllerTwo;

Use the TextField's onChanged: (value) {} to call a method that handles the _disabled variable:

TextField(
  controller: _controllerOne,
  onChanged: (text) {
    _setDisabled();
  },
),

_setDisabled() {
   if (_controllerOne.text != "" && _controllerTwo.text != "") {
      setState(() {_disabled = false;});
   } else {
      setState(() {_disabled = true;});
   }
}