在 Flutter 中制作自定义小部件时，onPress 不起作用

Question

i have some issue don't know what happanning when make custom widget class and pass onpress function its not working.

RoundButton dart file

class RoundedButton extends StatelessWidget {
  final String text;
  final Function press;
  final Color color, textColor;

  const RoundedButton({
    Key? key,
    required this.text,
    required this.press,
    this.color = primaryColor,
    this.textColor = Colors.white,
  }) : super(key: key);

  @override
  Widget build(BuildContext context) {
    Size size = MediaQuery.of(context).size;
    return Container(
      margin: EdgeInsets.symmetric(vertical: 8),
      width: size.width * 0.8,
      child: ClipRRect(
        borderRadius: BorderRadius.circular(30),
        child: TextButton(
          onPressed: press(),
          child: Text(text),
          style: TextButton.styleFrom(
              backgroundColor: color,
              primary: textColor,
              padding: EdgeInsets.symmetric(vertical: 16, horizontal: 40)),
        ),
      ),
    );
  }
}

Where I call that widget.

RoundedButton(
          text: "LOGIN",
          press: () {
            Navigator.push(
              context,
              MaterialPageRoute(
                builder: (context) {
                  return LoginScreen();
                },
              ),
            );
          },
        )

I tried like but not working

onPressed: press()

onPressed: (){press;}

onPressed: () =>press

But when I add the Navigation function directly at the RoundButton widget.

press: () {
        Navigator.push(
          context,
          MaterialPageRoute(
            builder: (context) {
              return LoginScreen();
            },
          ),
        )

It worked.

But don't know why custom function not working.

Answer 1

the only we need to do is add.call() to the end of the function to be void. onPressed: ()=>onPressed to onPressed: ()=>onPressed.call()

Answer 2

@override
  Widget build(BuildContext context) {
    Size size = MediaQuery.of(context).size;
    return Container(
      margin: EdgeInsets.symmetric(vertical: 8),
      width: size.width * 0.8,
      child: ClipRRect(
        borderRadius: BorderRadius.circular(30),
        child: TextButton(
          onPressed: press(),   // call just press ,here u r calling the func // right after the widget is rendered. Its worked fine for me in versions b4 //null safety.

 child: Text(text),
          style: TextButton.styleFrom(
              backgroundColor: color,
              primary: textColor,
              padding: EdgeInsets.symmetric(vertical: 16, horizontal: 40)),
        ),
      ),
    );
  }
}