android: add ActiveEventLoopExtAndroid::android_app

This type comes from the user and stored for the entire lifetime, so
no need to hide it from them after they've passed it to winit.

Fixes #3818.

src/changelog/unreleased.md

@@ -54,6 +54,7 @@ changelog entry.
   `ActiveEventLoop::request_detailed_monitor_permission()`, access to all monitors and their
   information is available. This "detailed monitors" can be used in `Window::set_fullscreen()` as
   well.
+- On Android, add `ActiveEventLoopExtAndroid::android_app` to access the app used to create the loop.
 
 ### Changed
 

src/platform/android.rs

@@ -80,7 +80,10 @@ pub trait EventLoopExtAndroid {}
 impl EventLoopExtAndroid for EventLoop {}
 
 /// Additional methods on [`ActiveEventLoop`] that are specific to Android.
-pub trait ActiveEventLoopExtAndroid {}
+pub trait ActiveEventLoopExtAndroid {
+    /// Get the `AndroidApp` which was used to create an event loop.
+    fn android_app(&self) -> &AndroidApp;
+}
 
 /// Additional methods on [`Window`] that are specific to Android.
 pub trait WindowExtAndroid {
@@ -99,7 +102,11 @@ impl WindowExtAndroid for Window {
     }
 }
 
-impl ActiveEventLoopExtAndroid for ActiveEventLoop {}
+impl ActiveEventLoopExtAndroid for ActiveEventLoop {
+    fn android_app(&self) -> &AndroidApp {
+        &self.p.app
+    }
+}
 
 /// Additional methods on [`WindowAttributes`] that are specific to Android.
 pub trait WindowAttributesExtAndroid {}

src/platform_impl/android/mod.rs

@@ -98,7 +98,7 @@ impl RedrawRequester {
 pub struct KeyEventExtra {}
 
 pub struct EventLoop {
-    android_app: AndroidApp,
+    pub(crate) android_app: AndroidApp,
     window_target: event_loop::ActiveEventLoop,
     redraw_flag: SharedFlag,
     loop_running: bool, // Dispatched `NewEvents<Init>`
@@ -575,7 +575,7 @@ impl EventLoopProxy {
 }
 
 pub struct ActiveEventLoop {
-    app: AndroidApp,
+    pub(crate) app: AndroidApp,
     control_flow: Cell<ControlFlow>,
     exit: Cell<bool>,
     redraw_requester: RedrawRequester,