Fix window close in example cause panic (#17533)

# Objective

Fixes #17532 

## Solution

- check window valide

examples/2d/2d_viewport_to_world.rs

@@ -12,9 +12,13 @@ fn main() {
 
 fn draw_cursor(
     camera_query: Single<(&Camera, &GlobalTransform)>,
-    window: Single<&Window>,
+    window: Query<&Window>,
     mut gizmos: Gizmos,
 ) {
+    let Ok(window) = window.get_single() else {
+        return;
+    };
+
     let (camera, camera_transform) = *camera_query;
 
     let Some(cursor_position) = window.cursor_position() else {

examples/3d/3d_viewport_to_world.rs

@@ -13,9 +13,13 @@ fn main() {
 fn draw_cursor(
     camera_query: Single<(&Camera, &GlobalTransform)>,
     ground: Single<&GlobalTransform, With<Ground>>,
-    windows: Single<&Window>,
+    windows: Query<&Window>,
     mut gizmos: Gizmos,
 ) {
+    let Ok(windows) = windows.get_single() else {
+        return;
+    };
+
     let (camera, camera_transform) = *camera_query;
 
     let Some(cursor_position) = windows.cursor_position() else {

examples/ecs/observers.rs

@@ -172,9 +172,13 @@ fn draw_shapes(mut gizmos: Gizmos, mines: Query<&Mine>) {
 fn handle_click(
     mouse_button_input: Res<ButtonInput<MouseButton>>,
     camera: Single<(&Camera, &GlobalTransform)>,
-    windows: Single<&Window>,
+    windows: Query<&Window>,
     mut commands: Commands,
 ) {
+    let Ok(windows) = windows.get_single() else {
+        return;
+    };
+
     let (camera, camera_transform) = *camera;
     if let Some(pos) = windows
         .cursor_position()

examples/ecs/parallel_query.rs

@@ -42,7 +42,10 @@ fn move_system(mut sprites: Query<(&mut Transform, &Velocity)>) {
 }
 
 // Bounce sprites outside the window
-fn bounce_system(window: Single<&Window>, mut sprites: Query<(&Transform, &mut Velocity)>) {
+fn bounce_system(window: Query<&Window>, mut sprites: Query<(&Transform, &mut Velocity)>) {
+    let Ok(window) = window.get_single() else {
+        return;
+    };
     let width = window.width();
     let height = window.height();
     let left = width / -2.0;

examples/games/contributors.rs

@@ -252,10 +252,14 @@ fn gravity(time: Res<Time>, mut velocity_query: Query<&mut Velocity>) {
 /// velocity. On collision with the ground it applies an upwards
 /// force.
 fn collisions(
-    window: Single<&Window>,
+    window: Query<&Window>,
     mut query: Query<(&mut Velocity, &mut Transform), With<Contributor>>,
     mut rng: ResMut<SharedRng>,
 ) {
+    let Ok(window) = window.get_single() else {
+        return;
+    };
+
     let window_size = window.size();
 
     let collision_area = Aabb2d::new(Vec2::ZERO, (window_size - SPRITE_SIZE) / 2.);

examples/mobile/src/lib.rs

@@ -46,12 +46,16 @@ fn main() {
 }
 
 fn touch_camera(
-    window: Single<&Window>,
+    window: Query<&Window>,
     mut touches: EventReader<TouchInput>,
     mut camera_transform: Single<&mut Transform, With<Camera3d>>,
     mut last_position: Local<Option<Vec2>>,
     mut rotations: EventReader<RotationGesture>,
 ) {
+    let Ok(window) = window.get_single() else {
+        return;
+    };
+
     for touch in touches.read() {
         if touch.phase == TouchPhase::Started {
             *last_position = None;

examples/stress_tests/bevymark.rs

@@ -327,12 +327,16 @@ fn mouse_handler(
     args: Res<Args>,
     time: Res<Time>,
     mouse_button_input: Res<ButtonInput<MouseButton>>,
-    window: Single<&Window>,
+    window: Query<&Window>,
     bird_resources: ResMut<BirdResources>,
     mut counter: ResMut<BevyCounter>,
     mut rng: Local<Option<ChaCha8Rng>>,
     mut wave: Local<usize>,
 ) {
+    let Ok(window) = window.get_single() else {
+        return;
+    };
+
     if rng.is_none() {
         // We're seeding the PRNG here to make this example deterministic for testing purposes.
         // This isn't strictly required in practical use unless you need your app to be deterministic.
@@ -529,7 +533,11 @@ fn handle_collision(half_extents: Vec2, translation: &Vec3, velocity: &mut Vec3)
         velocity.y = 0.0;
     }
 }
-fn collision_system(window: Single<&Window>, mut bird_query: Query<(&mut Bird, &Transform)>) {
+fn collision_system(window: Query<&Window>, mut bird_query: Query<(&mut Bird, &Transform)>) {
+    let Ok(window) = window.get_single() else {
+        return;
+    };
+
     let half_extents = 0.5 * window.size();
 
     for (mut bird, transform) in &mut bird_query {