Invalid constant value on Textformfield

Question

I try to do show and hide password but it says Invalid constant value on the _togglePasswordView, And _isHidden I wonder what I did wrong If someone know plz help

bool _isHidden = true;

 void _togglePasswordView() {
 setState(() {
  _isHidden = !_isHidden;
  });
}

TextFormField(
          obscureText: _isHidden,
          decoration: const InputDecoration(
            hintText: 'Password',
            suffix: InkWell(
              onTap: _togglePasswordView,
              child: Icon(
                _isHidden ? Icons.visibility : Icons.visibility_off,
              ),
            ),
          ),
        ),

score 1 · Answer 1 · answered May 03 '22 at 10:30

So lets make it clear about const keyword. When you use const keyword - you define a value constant from compile-time. It means - its value must be defined before the program even runs. So you may not but any run-time (created at some time when program is running) variables or conditions into constant constructors. Just remove the constant keyword.

score 0 · Answer 2 · answered May 03 '22 at 07:29

0

You're using something dynamic (here onTap function), inside a const constructor call

JUST REMOVE const KEYWORD and you'll be fine

answered May 03 '22 at 07:29

Shanu

311
2
16

score 0 · Answer 3 · answered May 04 '22 at 20:27

const Keyword means your variable will not change at application run-time.

what you're doing is saying to the complier that make TextFormField constant it will not change. while you changing the icon through run-time.

Just remove const and you well be fine

Invalid constant value on Textformfield

3 Answers3