Dispose isn't called when the widgets removed from the window - Flutter

Question

I am using the same stateful widget in 2 different views. It's using a list of TextEditingController that I send as a delegate through

this is the list of TextControllers :

var textfieldControllersEx = [
  TextEditingController(),
  TextEditingController(),
  TextEditingController(),
  TextEditingController(),
];

the Extracted widget is used twice in 2 different views:

ExpiryDateTextField(
  controllers: textfieldControllersEx,
  onChangeF: (String value, int i) {
    setState(() {
        _addValuesToAr(value, i);
    });
  },
),

on every view I call a dispose and a dispose in the ExpiryDateTextField Function as well with a print to see if it's being disposed:

It doesn't even call the dispose on either pages

@override
  void dispose() {
    Print.yellow('DISPOSED');
    textfieldControllersEx[0].dispose();
    textfieldControllersEx[1].dispose();
    textfieldControllersEx[2].dispose();
    textfieldControllersEx[3].dispose();
    textfieldControllersEx[0].text = null;
    textfieldControllersEx[1].text = null;
    textfieldControllersEx[2].text = null;
    textfieldControllersEx[3].text = null;
    // TODO: implement dispose
    super.dispose();
  }

this is the function :

var focusNodes = [
  FocusNode(),
  FocusNode(),
  FocusNode(),
  FocusNode(),
];
class ExpiryDateTextField extends StatefulWidget {
  final List<TextEditingController> controllers;
  final Function onChangeF;
  ExpiryDateTextField({this.controllers, this.onChangeF});
  @override
  _ExpiryDateTextFieldState createState() => _ExpiryDateTextFieldState();
}
class _ExpiryDateTextFieldState extends State<ExpiryDateTextField> {
  @override
  void dispose() {
    // TODO: implement dispose
    super.dispose();
  }
  @override
  Widget build(BuildContext context) {
    bool onSwitchChanged(value, context, index) {
      // print(index++);
      if (index == 4) {
        //if it is on the last text box, do nothing
      } else {
        if (widget.controllers[index].text.length > 0) {
          index++;
          FocusScope.of(context).requestFocus(focusNodes[index]);
          widget.controllers[index].selection = TextSelection(
            baseOffset: 0,
            extentOffset: widget.controllers[index].text.length
          );
          // FocusScope.of(context).focus
        }
      }
      return true;
    }
    return Row(
      children: <Widget>[
        Expanded(
          flex: 1,
          child: SingleDigitTextField(
            onChangedF: (value) {
              widget.onChangeF(value, 0);
              print(this.toString(minLevel: DiagnosticLevel.debug));
              onSwitchChanged(value, context, 0);
            },
            fNode: focusNodes[0],
            cController: widget.controllers[0]
          ),
        ),
        Expanded(
          flex: 1,
          child: SingleDigitTextField(
            onChangedF: (value) {
              widget.onChangeF(value, 1);
              onSwitchChanged(value, context, 1);
            },
            fNode: focusNodes[1],
            cController: widget.controllers[1]
          ),
        ),
        Expanded(
          flex: 1,
          child: Text("/",
            textAlign: TextAlign.center,
            style: Theme.of(context).textTheme.display2
          ),
        ),
        Expanded(
          flex: 1,
          child: SingleDigitTextField(
            onChangedF: (value) {
              widget.onChangeF(value, 2);
              onSwitchChanged(value, context, 2);
            },
            fNode: focusNodes[2],
            cController: widget.controllers[2]
          ),
        ),
        Expanded(
          flex: 1,
          child: SingleDigitTextField(
            onChangedF: (value) {
              widget.onChangeF(value, 3);
              onSwitchChanged(value, context, 3);
            },
            fNode: focusNodes[3],
            cController: widget.controllers[3]
          ),
        ),
      ],
    );
  }
}

this is the error given :

I/flutter (24293): Another exception was thrown: dependOnInheritedWidgetOfExactType<_ModalScopeStatus>() or dependOnInheritedElement() was called before _ViewState.initState() completed.

I saw this example but it didn't work because if a value is changed it disposes of the TextControllers immediately :

@override
  void didChangeDependencies() {
    textfieldControllersEx[0].dispose();
    textfieldControllersEx[1].dispose();
    textfieldControllersEx[2].dispose();
    textfieldControllersEx[3].dispose();
    // TODO: implement didChangeDependencies
    super.didChangeDependencies();
  }

this is how I Navigate :

Navigator.of(context).pushNamed("/PlaidPage");

Help would be kindly appreciated

Solution

The reason why dispose() isn't called is because the Screen is still on the Navigation stack. You can remove the current screen by either using Navigator.pop() or Navigator.of(context).pushNamedAndRemoveUntil() - to remove till the specified page and navigate to the next page.

Comments

[Manuel]

I'm not quite sure, but don't you need a Navigator.of(context).pushNamedAndRemoveUntil("/PlaidPage"); Otherwise the view is still on "behind" on the push/pop stack and the widgets are not disposed

[Michel Feinstein]

Could you simplify your question with a smaller example? Try creating a new project and just place there the minimum amount of code to reproduce the issue.

[Dohan Smit]

Thanks, @Manuel... I just needed to insert a Navigator.pop(context); before I use Navigator.of(context).pushNamed"/PlaidPage");

[morgwai]

there's an ongoing discussion regarding this on github. Please voice your support if you think it should be fixed in flutter