How to strongly type a method in Dart?-CodePudding

I am passing a method to another Class and storing it in a variable, how do I strongly type it?

...
  Class2(someMethod);
...
void someMethod();

Class2 {
  final dynamic thatMethod;
  Class2(this.thatMethod);
}

Checking the runtimeType returns () => void,

CodePudding user response：

According to https://dart.dev/guides/language/effective-dart/design#prefer-signatures-in-function-type-annotations

you can do Class2(returnTypeOfFn Function(inputArgType) fn)

eg Class(void Function() fn) to accept only ()=>void functions

runnable example

void main() {
  acceptFunction(() => print('hi there'));
  acceptFunction((String trd) => print('this is invalid'));
  acceptFunction(()=>return "Still invalid");
}

acceptFunction(void Function() func) {
  func.call();
}

first line is valid