textfield onChanged() {setstate} doesn't work in flutter

Question

I wanna change color of button when user type at least one character on textfield also wanna change color when textfield is empty

so I tryed to flag(boolean) to make it

onChanged: (value) {
    if (value.length == 0) {
      setState(() {
        _isTimeFilled = false;
      });
    } else {
      setState(() {
        _isTimeFilled = true;
      });
    }
},

...

_isFilled ? Colors.grey : Colors.green

but it only change color when textfield unfocused

i tryed provider too but it's same. how can i fix this?

here's my code

    void _changeButtonColor(int value) {✅✅✅✅
    if (value == 0) {
      setState(() => _isTimeFilled = false);
    } else {
      setState(() => _isTimeFilled = true);
    }
  }
  
    TextFormField TimeTextFormField() {
    return TextFormField(
      focusNode: timeFocusNode,
      autofocus: true,
      keyboardType: TextInputType.number,
      textInputAction: TextInputAction.next,
      onChanged: (value) {
        _changeButtonColor(value.length);✅✅✅✅
      },
      
      
      RaisedButton(
            focusColor: Colors.white,
            splashColor: Colors.white,
            shape: RoundedRectangleBorder(
              borderRadius: BorderRadius.circular(6.0),
            ),
            onPressed: () {},
            color: _isTimeFilled ? Colors.greenAccent : Colors.grey, ✅✅✅✅
            textColor: Colors.white,
            child: Padding(
              padding: const EdgeInsets.all(8.0),
              child: SizedBox(
                  width: double.infinity, child: Icon(Icons.check)),
            ),
          ),
        ),

Check your variable _isTimeFilled must be above @override build. — Raine Dale Holgado
– Raine Dale Holgado, Commented Oct 11, 2020 at 3:13

Dan Gerchcovich · Accepted Answer · 2020-10-11 02:48:14Z

6

Do this:

onChanged: (value) {
    _isTimeFilled = (value != 0);
    setState(() { });
},

answered Oct 11, 2020 at 2:48

Dan Gerchcovich

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Comments

Yuu Woods · Accepted Answer · 2020-10-11 02:53:07Z

1

The onChanged of a TextField is a string as an argument. And, _isFilled and _isTimeFilled need to be unified.

So,

onChanged: (value) {
  if (value.length <= 0) {
    setState(() {
      _isFilled = false;
    });
  } else {
    setState(() {
      _isFilled = true;
    });
  }
},

answered Oct 11, 2020 at 2:53

Yuu Woods

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Comments

SILENMUS · Accepted Answer · 2021-12-25 15:52:24Z

0

Found solution but don't know exactly the cause. Just managed to make it.

solution: make a stateful widget and call it.

floatingActionButton: FloatingActionButton(
        onPressed: () {
          showCupertinoModalBottomSheet(
            context: context,
            builder: (context, scrollController) => inputForms(),
          );
        },

inputForms is method which return form fields.

solution: make form fields stateful widget and import it

floatingActionButton: FloatingActionButton(
    onPressed: () {
        showCupertinoModalBottomSheet(
        context: context,
        builder: (context, scrollController) => StatefulFormFields(),
    );
},

edited Dec 25, 2021 at 15:52

user17242583

answered Oct 11, 2020 at 5:30

SILENMUS

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