ContextMenuArea: Intercept long press on Android

api/cpp/cbindgen.rs

@@ -235,7 +235,9 @@ fn default_config() -> cbindgen::Config {
     config.defines = [
         ("target_pointer_width = 64".into(), "SLINT_TARGET_64".into()),
         ("target_pointer_width = 32".into(), "SLINT_TARGET_32".into()),
-        ("target_arch = wasm32".into(), "SLINT_TARGET_WASM".into()), // Disable any wasm guarded code in C++, too - so that there are no gaps in enums.
+        // Disable any wasm guarded code in C++, too - so that there are no gaps in enums.
+        ("target_arch = wasm32".into(), "SLINT_TARGET_WASM".into()),
+        ("target_os = android".into(), "__ANDROID__".into()),
     ]
     .iter()
     .cloned()

docs/astro/src/content/docs/reference/window/contextmenuarea.mdx

@@ -10,6 +10,7 @@ Use the non-visual `ContextMenuArea` element to declare an area where the user c
 
 The context menu is shown if the user right-clicks on the area covered by the `ContextMenuArea` element,
 or if the user presses the "Menu" key on their keyboard while a `FocusScope` within the `ContextMenuArea` has focus.
+On Android, the menu is shown with a long press.
 Call the `show()` function on the `ContextMenuArea` element to programmatically show the context menu.
 
 One of the children of the `ContextMenuArea` must be a `Menu` element, which defines the menu to be shown.

internal/backends/android-activity/lib.rs

@@ -18,6 +18,7 @@ pub use android_activity::AndroidApp;
 use android_activity::PollEvent;
 use androidwindowadapter::AndroidWindowAdapter;
 use core::ops::ControlFlow;
+use core::time::Duration;
 use i_slint_core::api::{EventLoopError, PlatformError};
 use i_slint_core::platform::{Clipboard, WindowAdapter};
 use i_slint_renderer_skia::SkiaRendererExt;
@@ -100,7 +101,7 @@ impl i_slint_core::platform::Platform for AndroidPlatform {
             let mut timeout = i_slint_core::platform::duration_until_next_timer_update();
             if self.window.window.has_active_animations() {
                 // FIXME: we should not hardcode a value here
-                let frame_duration = std::time::Duration::from_millis(10);
+                let frame_duration = Duration::from_millis(10);
                 timeout = Some(match timeout {
                     Some(x) => x.min(frame_duration),
                     None => frame_duration,
@@ -152,6 +153,10 @@ impl i_slint_core::platform::Platform for AndroidPlatform {
             None
         }
     }
+
+    fn long_press_interval(&self, _: i_slint_core::InternalToken) -> Duration {
+        self.window.java_helper.long_press_timeout().unwrap_or(Duration::from_millis(500))
+    }
 }
 
 enum Event {

internal/core/items.rs

@@ -1216,6 +1216,8 @@ pub struct ContextMenu {
     pub show: Callback<PointArg>,
     pub cached_rendering_data: CachedRenderingData,
     pub popup_id: Cell<Option<NonZeroU32>>,
+    #[cfg(target_os = "android")]
+    long_press_timer: Cell<Option<crate::timers::Timer>>,
 }
 
 impl Item for ContextMenu {
@@ -1244,11 +1246,40 @@ impl Item for ContextMenu {
         _window_adapter: &Rc<dyn WindowAdapter>,
         _self_rc: &ItemRc,
     ) -> InputEventResult {
-        if let MouseEvent::Pressed { position, button: PointerEventButton::Right, .. } = event {
-            self.show.call(&(crate::api::LogicalPosition::from_euclid(position),));
-            InputEventResult::EventAccepted
-        } else {
-            InputEventResult::EventIgnored
+        match event {
+            MouseEvent::Pressed { position, button: PointerEventButton::Right, .. } => {
+                self.show.call(&(crate::api::LogicalPosition::from_euclid(position),));
+                InputEventResult::EventAccepted
+            }
+            #[cfg(target_os = "android")]
+            MouseEvent::Pressed { position, button: PointerEventButton::Left, .. } => {
+                let timer = crate::timers::Timer::default();
+                let self_weak = _self_rc.downgrade();
+                timer.start(
+                    crate::timers::TimerMode::SingleShot,
+                    WindowInner::from_pub(_window_adapter.window())
+                        .ctx
+                        .platform()
+                        .long_press_interval(crate::InternalToken),
+                    move || {
+                        let Some(self_rc) = self_weak.upgrade() else { return };
+                        let Some(self_) = self_rc.downcast::<ContextMenu>() else { return };
+                        self_.show.call(&(crate::api::LogicalPosition::from_euclid(position),));
+                    },
+                );
+                self.long_press_timer.set(Some(timer));
+                InputEventResult::GrabMouse
+            }
+            #[cfg(target_os = "android")]
+            MouseEvent::Released { .. } | MouseEvent::Exit => {
+                if let Some(timer) = self.long_press_timer.take() {
+                    timer.stop();
+                }
+                InputEventResult::EventIgnored
+            }
+            #[cfg(target_os = "android")]
+            MouseEvent::Moved { .. } => InputEventResult::EventAccepted,
+            _ => InputEventResult::EventIgnored,
         }
     }
 

internal/core/platform.rs

@@ -126,6 +126,13 @@ pub trait Platform {
     fn debug_log(&self, _arguments: core::fmt::Arguments) {
         crate::tests::default_debug_log(_arguments);
     }
+
+    #[cfg(target_os = "android")]
+    #[doc(hidden)]
+    /// The long press interval before showing a context menu
+    fn long_press_interval(&self, _: crate::InternalToken) -> core::time::Duration {
+        core::time::Duration::from_millis(500)
+    }
 }
 
 /// The clip board, used in [`Platform::clipboard_text`] and [Platform::set_clipboard_text`]