feat(mobile): add multi window support

.changes/android-breaking-changes.md

@@ -0,0 +1,16 @@
+---
+"tao": minor
+---
+
+**Breaking change:** The Android activity should now reference and call the following external functions:
+
+```
+private external fun onActivityCreate(activity)
+private external fun start()
+private external fun resume()
+private external fun pause()
+private external fun stop()
+private external fun onActivitySaveInstanceState()
+private external fun onActivityDestroy(activity)
+private external fun onActivityLowMemory()
+```

.changes/multi-window-mobile.md

@@ -0,0 +1,18 @@
+---
+"tao": minor
+---
+
+Added multi-window support for iOS and Android.
+
+Leverages [scenes](https://developer.apple.com/documentation/uikit/scenes) on iOS and [Activity embedding](https://developer.android.com/develop/ui/views/layout/activity-embedding) on Android.
+
+iOS:
+
+- Added Event::SceneRequested (on iPad the user can request a new window to be open - e.g. by long pressing the app icon and selecting "New window")
+- Request new scene to be created on Window::new (if needed, main scene is detected automatically) and assign the window instance later when it gets connected
+
+Android:
+
+- Create new activity on Window::new (if needed, main activity is detected automatically)
+- Added builder methods to determine the activity to be created
+- System determines what to do with the activity (new stack, next to another one.. based on the embedding rules)

Cargo.toml

@@ -4,48 +4,52 @@ version = "0.34.5"
 description = "Cross-platform window manager library."
 authors = [
   "Tauri Programme within The Commons Conservancy",
-  "The winit contributors"
+  "The winit contributors",
 ]
 edition = "2021"
 rust-version = "1.74"
-keywords = [ "windowing" ]
+keywords = ["windowing"]
 license = "Apache-2.0"
 readme = "README.md"
 repository = "https://github.com/tauri-apps/tao"
 documentation = "https://docs.rs/tao"
-categories = [ "gui" ]
+categories = ["gui"]
 include = ["/README.md", "src/**/*.rs", "examples/**/*.rs", "LICENSE*"]
 
 [package.metadata.docs.rs]
-features = [ "rwh_04", "rwh_05", "rwh_06", "serde", "x11" ]
+features = ["rwh_04", "rwh_05", "rwh_06", "serde", "x11"]
 default-target = "x86_64-unknown-linux-gnu"
 targets = [
   "i686-pc-windows-msvc",
   "x86_64-pc-windows-msvc",
   "i686-unknown-linux-gnu",
   "x86_64-unknown-linux-gnu",
-  "x86_64-apple-darwin"
+  "x86_64-apple-darwin",
 ]
 
 [features]
-default = [ "rwh_06", "x11" ]
-serde = [ "dep:serde", "dpi/serde" ]
-rwh_04 = [ "dep:rwh_04" ]
-rwh_05 = [ "dep:rwh_05" ]
-rwh_06 = [ "dep:rwh_06" ]
-x11 = [ "dep:gdkx11-sys", "dep:x11-dl" ]
+default = ["rwh_06", "x11"]
+serde = ["dep:serde", "dpi/serde"]
+rwh_04 = ["dep:rwh_04"]
+rwh_05 = ["dep:rwh_05"]
+rwh_06 = ["dep:rwh_06"]
+x11 = ["dep:gdkx11-sys", "dep:x11-dl"]
 
 [workspace]
-members = [ "tao-macros" ]
+members = ["tao-macros"]
 
 [dependencies]
 lazy_static = "1"
 libc = "0.2"
 log = "0.4"
-serde = { version = "1", optional = true, features = [ "serde_derive" ] }
+serde = { version = "1", optional = true, features = ["serde_derive"] }
 rwh_04 = { package = "raw-window-handle", version = "0.4", optional = true }
-rwh_05 = { package = "raw-window-handle", version = "0.5", features = [ "std" ], optional = true }
-rwh_06 = { package = "raw-window-handle", version = "0.6", features = [ "std" ], optional = true }
+rwh_05 = { package = "raw-window-handle", version = "0.5", features = [
+  "std",
+], optional = true }
+rwh_06 = { package = "raw-window-handle", version = "0.6", features = [
+  "std",
+], optional = true }
 bitflags = "2"
 crossbeam-channel = "0.5"
 url = "2"
@@ -64,9 +68,9 @@ unicode-segmentation = "1.11"
 windows-version = "0.1"
 windows-core = "0.61"
 
-  [target."cfg(target_os = \"windows\")".dependencies.windows]
-  version = "0.61"
-  features = [
+[target."cfg(target_os = \"windows\")".dependencies.windows]
+version = "0.61"
+features = [
   "Win32_Devices_HumanInterfaceDevice",
   "Win32_Foundation",
   "Win32_Globalization",
@@ -92,7 +96,7 @@ windows-core = "0.61"
   "Win32_UI_Input_Touch",
   "Win32_UI_Shell",
   "Win32_UI_TextServices",
-  "Win32_UI_WindowsAndMessaging"
+  "Win32_UI_WindowsAndMessaging",
 ]
 
 [target."cfg(any(target_os = \"android\", target_os = \"windows\"))".dependencies]
@@ -102,7 +106,6 @@ once_cell = "1"
 jni = "0.21"
 ndk = "0.9"
 ndk-sys = "0.6"
-ndk-context = "0.1"
 tao-macros = { version = "0.1.0", path = "./tao-macros" }
 
 [target."cfg(any(target_os = \"ios\", target_os = \"macos\"))".dependencies]
@@ -142,13 +145,22 @@ objc2-app-kit = { version = "0.3", default-features = false, features = [
   "NSScreen",
   "NSView",
   "NSWindow",
-  "NSUserActivity"
+  "NSUserActivity",
 ] }
 core-foundation = "0.10"
 core-graphics = "0.24"
 dispatch = "0.2"
 scopeguard = "1.2"
 
+[target."cfg(target_os = \"ios\")".dependencies]
+objc2-ui-kit = { version = "0.3", features = [
+  "UIResponder",
+  "UIScene",
+  "UISceneOptions",
+  "UIOpenURLContext",
+] }
+objc2-foundation = { version = "0.3", default-features = false }
+
 [target."cfg(any(target_os = \"linux\", target_os = \"dragonfly\", target_os = \"freebsd\", target_os = \"openbsd\", target_os = \"netbsd\"))".dependencies]
 gtk = "0.18"
 gdkx11-sys = { version = "0.18", optional = true }

src/event.rs

@@ -142,6 +142,21 @@ pub enum Event<'a, T: 'static> {
   /// - **Other**: Unsupported.
   #[non_exhaustive]
   Reopen { has_visible_windows: bool },
+
+  /// Emitted when a scene is requested by the system.
+  ///
+  /// This event is emitted when a scene is requested by the system.
+  /// Scenes created by tao's window builder are not emitted with this event.
+  /// It is also not emitted for the main scene.
+  #[cfg(target_os = "ios")]
+  SceneRequested {
+    /// Scene that was requested by the system.
+    scene: objc2::rc::Retained<objc2_ui_kit::UIScene>,
+    /// Options that were used to request the scene.
+    ///
+    /// This lets you determine why the scene was requested.
+    options: objc2::rc::Retained<objc2_ui_kit::UISceneConnectionOptions>,
+  },
 }
 
 impl<T: Clone> Clone for Event<'static, T> {
@@ -170,6 +185,11 @@ impl<T: Clone> Clone for Event<'static, T> {
       } => Reopen {
         has_visible_windows: *has_visible_windows,
       },
+      #[cfg(target_os = "ios")]
+      SceneRequested { scene, options } => SceneRequested {
+        scene: scene.clone(),
+        options: options.clone(),
+      },
     }
   }
 }
@@ -194,6 +214,8 @@ impl<'a, T> Event<'a, T> {
       } => Ok(Reopen {
         has_visible_windows,
       }),
+      #[cfg(target_os = "ios")]
+      SceneRequested { scene, options } => Ok(SceneRequested { scene, options }),
     }
   }
 
@@ -220,6 +242,8 @@ impl<'a, T> Event<'a, T> {
       } => Some(Reopen {
         has_visible_windows,
       }),
+      #[cfg(target_os = "ios")]
+      SceneRequested { scene, options } => Some(SceneRequested { scene, options }),
     }
   }
 }