Failed assertion: line 742 pos 12: 'attached': is not true.

[easazade]

the error and the stack trace

'package:flutter/src/services/text_input.dart': Failed assertion: line 742 pos 12: 'attached': is not true.

The following assertion was thrown building TxtBuildEditable(state: _TxtBuildEditableState#e1377):
'package:flutter/src/services/text_input.dart': Failed assertion: line 742 pos 12: 'attached': is not true.

Either the assertion indicates an error in the framework itself, or we should provide substantially more information in this error message to help you determine and fix the underlying cause.
In either case, please report this assertion by filing a bug on GitHub:
https://github.com/flutter/flutter/issues/new?template=BUG.md

The relevant error-causing widget was:
Txt file:///C:/workspace/flutter/smart_school/lib/widgets/app_text_field.dart:25:14
When the exception was thrown, this was the stack:
#2 TextInputConnection.setStyle (package:flutter/src/services/text_input.dart:742:12)
#3 EditableTextState.didUpdateWidget (package:flutter/src/widgets/editable_text.dart:1162:29)
#4 StatefulElement.update (package:flutter/src/widgets/framework.dart:4396:58)
#5 Element.updateChild (package:flutter/src/widgets/framework.dart:2977:15)
#6 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243:16)

here is the code i use as a textField widget in my app. now it works fine but i get this error when i'm using multiple instances of this widget in a page. when i tap first field keyboard pops up and the i tap on another field suddenly error happens. and that only happens if the first field (or any other ) still has the focus.

class AppTextField extends StatefulWidget {
  final StringCallback onChange;
  final String hint;
  final TextInputType inputType;

  AppTextField(this.onChange, {this.hint,this.inputType});

  @override
  State<StatefulWidget> createState() => _AppTextField();
}

class _AppTextField extends State<AppTextField> {
  String value = '';

  @override
  Widget build(BuildContext context) {
    return Container(
      decoration: BoxDecoration(color: AppColors.THEME_GREY, borderRadius: BorderRadius.circular(6)),
      child: Txt(
        '',
        style: TxtStyle()
          ..fontSize(14)
          ..fontFamily(Fonts.SAMIM)
          ..padding(horizontal: 10,vertical: 5)
          ..editable(
            placeholder: widget.hint,
            maxLines: 1,
            onChange: widget.onChange,
            keyboardType: widget.inputType ?? TextInputType.text
          ),
      ),
    );
  }
}