How to pass a type to the initial state?

[H36615]

Hi. This might not be fully related to iced but figured this is the best place to ask this.

I'm trying to make this MVC-based model with iced being the UI layer. I'm trying to call a controller method after a button press, but not sure how I'm able to pass the controller to the state. I have the following reduced example in more-or-less pseudo code.

struct View {
    controller: &'static Controller,
}

impl View {
    fn new(&self, controller: &'static Controller) {
        self.controller = controller;

        // Btw any way to do this here properly? ("unused `std::result::Result` that must be used")
        // The `main()` file can not have any `iced` libraries.
        View::run(Settings::default());
    }
}

impl Sandbox for View {
    // ...

    // Error since no default for `controller` which I don't even want, but the passed controller instead.
    fn new() -> Self {
        Self::default()
    }

    fn update(&mut self, message: Message) {
        match message {
            Message::ButtonPressed => {
                // how to 'controller.do_something()'?
            }
        }
    }

    // ...
}

So after a button press I need to call controller.do_something() but cannot figure out how to do that since the controller is not in the same scope. How can I pass the controller to the View state and call its method in the event?

If you can find any more noob mistakes feel free to point them out.

[hecrj]

You can provide initial state by implementing the Application trait instead and leveraging the Flags associated type:

pub fn main() -> iced::Result {
    let controller = Controller::new();

    View::run(Settings::with_flags(Flags { controller }))
}

struct View {
    controller: Controller,
}

struct Flags {
    controller: Controller,
}

impl Application for View {
    type Flags = Flags;
    // ...

    fn new(flags: Flags) -> (Self, Command<Message>) {
        (Self { controller: flags.controller }, Command::none())
    }

    fn update(&mut self, message: Message) -> Command<Message> {
        match message {
            Message::ButtonPressed => {
                self.controller.do_something();
            }
        }

        Command::none()
    }

    // ...
}

[H36615]

This was exactly what I wanted. Thanks for the quick and to the point answer. Got it working now :)