Question

I want to do something like the following:

void handleClick(){
    //do stuff
}

void addHandlerToButton(){
    window.document.query('#somebutton').on.click.add(handleClick);
}

Dart editor’s static checking reports '() -> void' is not assignable to 'EventListener'

I have a feeling I’m missing something really obvious.

Answer 1

Click handlers gets the click event passed as a argument (so you for example can get the screen coordiantes, target element etc.). So your handler method signature must be

void handleClick(Event event){
    // do stuff with event
}

The error you are reciving is actually telling you that (although in a cryptic way):

‘() -> void’ is not assignable to ‘EventListener’

Here EventListener is basically any function type with signature void handle(Event event) so the function you add with on.click.add must match this signature.