如何在 Dart 中为单个变量分配两种不同的方法？

Question

Minimal reproducible code:

Future<void> foo(int i) async => print(i);
Future<void> bar(double d, bool b) async => print(b);

@override
Widget build(BuildContext context) {
  var flag = true;
  var onPressed = flag ? foo(1) : bar(0.0, true);
  return Scaffold(
    body: RaisedButton(
      onPressed: () => onPressed,
      child: Text('Button'),
    ),
  );
}

Problem:

The method gets called during build process because I'm åctually calling foo(1) . How to resolve this issue? I only want to get it done using one variable as shown above.

Answer 1

It seems like there is no way to do this. The closest thing that can be done is to change my variable to a method.

So,

Instead of

var onPressed = flag ? foo(1) : bar(0.0, true);

Use

void onPressed () => flag ? foo(1) : bar(0.0, true);