Struct fltk::app::GlobalState

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pub struct GlobalState<T: Send + Sync> { /* private fields */ }

Expand description

Represents global state

Implementations

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impl<T: Sync + Send + 'static> GlobalState<T>

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pub fn new(val: T) -> Self

Creates a new global state

Examples found in repository ?

examples/widget_id.rs (line 94)

fn main() {
    let counter = Counter { count: 0 };
    let _state = app::GlobalState::new(counter);
    let app = app::App::default().with_scheme(app::Scheme::Gtk);
    let mut wind = window::Window::default()
        .with_size(160, 200)
        .with_label("Counter");
    let col = group::Flex::default_fill().column();
    button::Button::default()
        .with_label("+")
        .on_trigger(increment); // passed by function object
    frame::Frame::default().with_label("0").with_id("my_frame"); // pass id here
    button::Button::default()
        .with_label("-")
        .on_trigger(|_| increment_by(-1)); // called in closure
    col.end();
    wind.make_resizable(true);
    wind.end();
    wind.show();

    app.run().unwrap();
}

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pub fn with<V: Clone, F: 'static + Fn(&mut T) -> V>(&self, cb: F) -> V

Modifies the global state by acquiring a mutable reference

Panics

Panics on state downcast errors

Examples found in repository ?

examples/widget_id.rs (lines 74-77)

fn increment_by(step: i32) {
    let mut frame: frame::Frame = from_id("my_frame").unwrap();
    let state = app::GlobalState::<Counter>::get();
    let count = state.with(move |c| {
        c.count += step;
        c.count
    });
    frame.set_label(&count.to_string());
}

// To pass a function object directly!
fn increment(_w: &mut impl WidgetExt) {
    let mut frame: frame::Frame = from_id("my_frame").unwrap();
    let state = app::GlobalState::<Counter>::get();
    let count = state.with(|c| {
        c.count += 1;
        c.count
    });
    frame.set_label(&count.to_string());
}

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pub fn get() -> Self

Gets the already initialized global state

Examples found in repository ?

examples/widget_id.rs (line 73)

fn increment_by(step: i32) {
    let mut frame: frame::Frame = from_id("my_frame").unwrap();
    let state = app::GlobalState::<Counter>::get();
    let count = state.with(move |c| {
        c.count += step;
        c.count
    });
    frame.set_label(&count.to_string());
}

// To pass a function object directly!
fn increment(_w: &mut impl WidgetExt) {
    let mut frame: frame::Frame = from_id("my_frame").unwrap();
    let state = app::GlobalState::<Counter>::get();
    let count = state.with(|c| {
        c.count += 1;
        c.count
    });
    frame.set_label(&count.to_string());
}