winit-sonoma-fix/examples/handling_close.rs
Francesca Frangipane eadd9a19b2
Replace Closed event with CloseRequested and Destroyed (#476)
* Replace Closed event with CloseRequested and Destroyed

Implements #434

The existing Closed event had ambiguous meaning, both in name and in
cross-platform behavior. Closed is now split into two more precise events:

* CloseRequested - the window has been requested to close, most commonly by
having clicked the window's close button. Whether or not you respond by
closing the window is up to you.

* Destroyed - the window has been destroyed, and can no longer be safely
used.

Most notably, now you can reliably implement classic patterns like
prompting the user to save their work before closing, and have the
opportunity to perform any necessary cleanup.

Migrating to the new API is straightforward. In most cases, you can simply
replace all existing usages of Closed with CloseRequested. For more
information, see the example programs, particularly handling_close and
multiwindow.

iOS applications must replace all usages of Closed with Destroyed, and
require no other changes.
2018-04-24 16:20:40 -04:00

75 lines
3.1 KiB
Rust

extern crate winit;
fn main() {
let mut events_loop = winit::EventsLoop::new();
let _window = winit::WindowBuilder::new()
.with_title("Your faithful window")
.build(&events_loop)
.unwrap();
let mut close_requested = false;
events_loop.run_forever(|event| {
use winit::WindowEvent::*;
use winit::ElementState::Released;
use winit::VirtualKeyCode::{N, Y};
match event {
winit::Event::WindowEvent { event, .. } => match event {
CloseRequested => {
// `CloseRequested` is sent when the close button on the window is pressed (or
// through whatever other mechanisms the window manager provides for closing a
// window). If you don't handle this event, the close button won't actually do
// anything.
// A common thing to do here is prompt the user if they have unsaved work.
// Creating a proper dialog box for that is far beyond the scope of this
// example, so here we'll just respond to the Y and N keys.
println!("Are you ready to bid your window farewell? [Y/N]");
close_requested = true;
// In applications where you can safely close the window without further
// action from the user, this is generally where you'd handle cleanup before
// closing the window. How to close the window is detailed in the handler for
// the Y key.
}
KeyboardInput {
input:
winit::KeyboardInput {
virtual_keycode: Some(virtual_code),
state: Released,
..
},
..
} => match virtual_code {
Y => {
if close_requested {
// This is where you'll want to do any cleanup you need.
println!("Buh-bye!");
// For a single-window application like this, you'd normally just
// break out of the event loop here. If you wanted to keep running the
// event loop (i.e. if it's a multi-window application), you need to
// drop the window. That closes it, and results in `Destroyed` being
// sent.
return winit::ControlFlow::Break;
}
}
N => {
if close_requested {
println!("Your window will continue to stay by your side.");
close_requested = false;
}
}
_ => (),
},
_ => (),
},
_ => (),
}
winit::ControlFlow::Continue
});
}