counter4/
counter4.rs

1use fltk::{app, button::Button, frame::Frame, group::Flex, prelude::*, window::Window};
2use std::cell::RefCell;
3use std::rc::Rc;
4
5pub struct MyEvent;
6
7impl MyEvent {
8    const CHANGED: i32 = 40;
9}
10
11#[derive(Clone)]
12pub struct Counter {
13    count: Rc<RefCell<i32>>,
14}
15
16impl Counter {
17    #[must_use]
18    pub fn new(val: i32) -> Self {
19        Counter {
20            count: Rc::from(RefCell::from(val)),
21        }
22    }
23
24    pub fn increment(&mut self) {
25        *self.count.borrow_mut() += 1;
26        app::handle_main(MyEvent::CHANGED).unwrap();
27    }
28
29    pub fn decrement(&mut self) {
30        *self.count.borrow_mut() -= 1;
31        app::handle_main(MyEvent::CHANGED).unwrap();
32    }
33
34    #[must_use]
35    pub fn value(&self) -> i32 {
36        *self.count.borrow()
37    }
38}
39
40fn main() -> Result<(), Box<dyn std::error::Error>> {
41    let app = app::App::default();
42    let counter = Counter::new(0);
43    let mut wind = Window::default().with_size(160, 200).with_label("Counter");
44    let mut flex = Flex::default_fill().column();
45    flex.set_margins(30, 40, 30, 40);
46    flex.set_pad(10);
47    let mut but_inc = Button::default().with_label("+");
48    let mut frame = Frame::default().with_label(&counter.value().to_string());
49    let mut but_dec = Button::default().with_label("-");
50    flex.end();
51    wind.end();
52    wind.show();
53
54    but_inc.set_callback({
55        let mut c = counter.clone();
56        move |_| c.increment()
57    });
58
59    but_dec.set_callback({
60        let mut c = counter.clone();
61        move |_| c.decrement()
62    });
63
64    frame.handle(move |f, ev| {
65        if ev == MyEvent::CHANGED.into() {
66            f.set_label(&counter.clone().value().to_string());
67            true
68        } else {
69            false
70        }
71    });
72
73    Ok(app.run()?)
74}
counter4/counter4.rs

counter4/
counter4.rs
