I have an alert dialog in my flutter web application:

  Widget _text() {
    return TextFormField(
      decoration: InputDecoration(
        contentPadding: const EdgeInsets.all(15),
        counterText: "$textLength",
      ),
      maxLength: maxLength,
      onChanged: (value) {
        controller.text = value;
        textLength = value.length;
        print("text length: $textLength");
        print("controller text length: ${controller.text.length}");
        setState(() {});
      },
    );
  }

and the entire alert dialog:

  showMyDialog() async {
    return showDialog(
      context: context,
      barrierDismissible: false,
      builder: (BuildContext context) {
        return AlertDialog(
          title: const Text(
            'Share your thoughts!',
            style: TextStyle(
              color: Colors.black,
              fontWeight: FontWeight.bold,
            ),
          ),
          content: SizedBox(
                _text(),
              ],
            ),
          ),
        );
      },
    );
  }

problem is the counter text is not updating. Can anyone point out why my counter text is not updating?

CodePudding user response：

Wrap AlertDialog with StatefulBuilder and use its setState.

 showMyDialog() async {
    return showDialog(
      context: context,
      barrierDismissible: false,
      builder: (BuildContext context) {
        return StatefulBuilder(
            builder: (context, setState) => AlertDialog(
                title: const Text(
                  'Share your thoughts!',
                  style: TextStyle(
                    color: Colors.black,
                    fontWeight: FontWeight.bold,
                  ),
                ),
                content: _text(setState)));
      },
    );
  }

And get the setState on _text method.

  Widget _text(setState) {
    return TextFormField(...);
  }