How to request window focus in Bevy 0.19

[QueenOfSquiggles]

Is there some kind of function available to have the window "request focus"? I'm honestly remembering back to time in Java where I would need to call that at window initialization. Is there anything I can do like that in Bevy? I was referencing the Window Settings example on the website, so I liked the delayed visibility of the window but I would also like to have the window request focus once it becomes visible.

[ryux1]

Yes. In Bevy 0.19, changing Window::focused from false to true makes bevy_winit call winit's focus_window().

There are two details worth handling in the delayed-visibility example:

1. focused defaults to true, so setting it to true later would not be a change and would not issue a new request.
2. Bevy propagates the focus change before the visibility change. Requesting both in the same update can therefore ask the backend to focus a window that is still hidden.

Start the window unfocused, show it, then request focus on the next update:

primary_window: Some(Window {
    visible: false,
    focused: false,
    ..default()
}),

fn make_visible_and_focus(
    mut window: Single<&mut Window>,
    frames: Res<FrameCount>,
) {
    match frames.0 {
        3 => window.visible = true,
        4 => window.focused = true,
        _ => {}
    }
}

If the platform focuses the window automatically when it becomes visible, the focus event may already have changed the component to true; assigning true again is harmless.

This is platform-dependent rather than guaranteed everywhere. Bevy 0.19 documents post-creation focus as unsupported on iOS, Android, Web, and Wayland. On supported desktop backends, it is still a request and the window manager may apply its own focus-stealing policy.

References in the 0.19 source: Window::focused and its platform notes, and the focus_window() call in bevy_winit.