how to inject function to other class in flutter - function

Question

I want to print 'test' when clicking MyButton
I made constructs with a function in my class but didn't work
please help me
here is my code
Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Text(
'bla bla bla',
),
MyButton((){print('test');}, 'my button')
],
),
I'm made a StatefulWidget class I called it MyButton
import 'package:flutter/material.dart';
class MyButton extends StatefulWidget {
Function buttonFunction;
String buttonName;
MyButton(this.buttonFunction,this.buttonName);
#override
_MyButtonState createState() => _MyButtonState();
}
class _MyButtonState extends State<MyButton> {
#override
Widget build(BuildContext context) {
String name=widget.buttonName;
return Container(
width: 200,
child: RaisedButton(
color: Colors.red,
onPressed: () {
widget.buttonFunction;
print('clicked $name');
},
textColor: Colors.white,
child: Text("$name",
style: TextStyle(fontSize: 18,),
),
),
);
}
}

Answer 1

You are missing the parenthesis "()" to call the function, instead you are just referencing it.
You are also setting a variable inside the build method which is the wrong place to declare variables, as it will re-run many times and be re-declared unnecessarily and become expensive. If you want to access the property of a value inside a String you just have to use `"String ${widget.myStringVariable}.".
I've modified your code to reflect these changes:
class _MyButtonState extends State<MyButton> {
#override
Widget build(BuildContext context) {
return Container(
width: 200,
child: RaisedButton(
color: Colors.red,
onPressed: () {
widget.buttonFunction();
print('clicked $name');
},
textColor: Colors.white,
child: Text("${widget.buttonName}",
style: TextStyle(fontSize: 18,),
),
),
);
}
}