bevy/examples/ui/button.rs
Carter Anderson b6a647cc01 default() shorthand (#4071)
Adds a `default()` shorthand for `Default::default()` ... because life is too short to constantly type `Default::default()`.

```rust
use bevy::prelude::*;

#[derive(Default)]
struct Foo {
  bar: usize,
  baz: usize,
}

// Normally you would do this:
let foo = Foo {
  bar: 10,
  ..Default::default()
};

// But now you can do this:
let foo = Foo {
  bar: 10,
  ..default()
};
```

The examples have been adapted to use `..default()`. I've left internal crates as-is for now because they don't pull in the bevy prelude, and the ergonomics of each case should be considered individually.
2022-03-01 20:52:09 +00:00

76 lines
2.5 KiB
Rust

use bevy::prelude::*;
/// This example illustrates how to create a button that changes color and text based on its
/// interaction state.
fn main() {
App::new()
.add_plugins(DefaultPlugins)
.add_startup_system(setup)
.add_system(button_system)
.run();
}
const NORMAL_BUTTON: Color = Color::rgb(0.15, 0.15, 0.15);
const HOVERED_BUTTON: Color = Color::rgb(0.25, 0.25, 0.25);
const PRESSED_BUTTON: Color = Color::rgb(0.35, 0.75, 0.35);
fn button_system(
mut interaction_query: Query<
(&Interaction, &mut UiColor, &Children),
(Changed<Interaction>, With<Button>),
>,
mut text_query: Query<&mut Text>,
) {
for (interaction, mut color, children) in interaction_query.iter_mut() {
let mut text = text_query.get_mut(children[0]).unwrap();
match *interaction {
Interaction::Clicked => {
text.sections[0].value = "Press".to_string();
*color = PRESSED_BUTTON.into();
}
Interaction::Hovered => {
text.sections[0].value = "Hover".to_string();
*color = HOVERED_BUTTON.into();
}
Interaction::None => {
text.sections[0].value = "Button".to_string();
*color = NORMAL_BUTTON.into();
}
}
}
}
fn setup(mut commands: Commands, asset_server: Res<AssetServer>) {
// ui camera
commands.spawn_bundle(UiCameraBundle::default());
commands
.spawn_bundle(ButtonBundle {
style: Style {
size: Size::new(Val::Px(150.0), Val::Px(65.0)),
// center button
margin: Rect::all(Val::Auto),
// horizontally center child text
justify_content: JustifyContent::Center,
// vertically center child text
align_items: AlignItems::Center,
..default()
},
color: NORMAL_BUTTON.into(),
..default()
})
.with_children(|parent| {
parent.spawn_bundle(TextBundle {
text: Text::with_section(
"Button",
TextStyle {
font: asset_server.load("fonts/FiraSans-Bold.ttf"),
font_size: 40.0,
color: Color::rgb(0.9, 0.9, 0.9),
},
Default::default(),
),
..default()
});
});
}