Add android ime support

src/event.rs

@@ -888,6 +888,19 @@ pub enum Ime {
     /// Right before this event winit will send empty [`Self::Preedit`] event.
     Commit(String),
 
+    /// Notifies when the complete text should be replaced.
+    /// This event should be used in combination with
+    /// [`Window::set_ime_surrounding_text`] to set the initial text of the
+    /// currently selected input field.
+    ///
+    /// ## Platform-specific
+    /// This will only be fired on **Android**.
+    Replace {
+        text: String,
+        selection: (usize, usize),
+        compose_region: Option<(usize, usize)>,
+    },
+
     /// Notifies when the IME was disabled.
     ///
     /// After receiving this event you won't get any more [`Preedit`](Self::Preedit) or

src/platform_impl/android/mod.rs

@@ -469,6 +469,24 @@ impl<T: 'static> EventLoop<T> {
                         }
                     }
                 }
+                InputEvent::TextEvent(ime_state) => {
+                    let event = event::Event::WindowEvent {
+                        window_id: window::WindowId(WindowId),
+                        event: event::WindowEvent::Ime(
+                            event::Ime::Replace {
+                                text: ime_state.text.to_string(),
+                                selection: (ime_state.selection.start, ime_state.selection.end),
+                                compose_region: ime_state.compose_region.map(|region| (region.start, region.end))
+                            }
+                        )
+                    };
+                    sticky_exit_callback(
+                        event,
+                        self.window_target(),
+                        control_flow,
+                        callback
+                    );
+                }
                 _ => {
                     warn!("Unknown android_activity input event {event:?}")
                 }
@@ -901,10 +919,28 @@ impl Window {
 
     pub fn set_ime_cursor_area(&self, _position: Position, _size: Size) {}
 
-    pub fn set_ime_allowed(&self, _allowed: bool) {}
+    pub fn set_ime_allowed(&self, allowed: bool) {
+        if allowed {
+            self.app.show_soft_input(true);
+        } else {
+            self.app.hide_soft_input(true);
+        }
+    }
 
     pub fn set_ime_purpose(&self, _purpose: ImePurpose) {}
 
+    pub fn set_ime_surrounding_text(&self, text: String, selection: (usize, usize)) {
+        self.app
+            .set_text_input_state(android_activity::input::TextInputState {
+                text,
+                selection: android_activity::input::TextSpan {
+                    start: selection.0,
+                    end: selection.1,
+                },
+                compose_region: None,
+            });
+    }
+
     pub fn focus_window(&self) {}
 
     pub fn request_user_attention(&self, _request_type: Option<window::UserAttentionType>) {}
@@ -987,6 +1023,7 @@ impl Window {
 pub struct OsError;
 
 use std::fmt::{self, Display, Formatter};
+
 impl Display for OsError {
     fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), fmt::Error> {
         write!(fmt, "Android OS Error")

src/platform_impl/ios/window.rs

@@ -306,6 +306,10 @@ impl Inner {
         warn!("`Window::set_ime_allowed` is ignored on iOS")
     }
 
+    pub fn set_ime_surrounding_text(&self, _text: String, _selection: (usize, usize)) {
+        warn!("`Window::set_ime_surrounding_text` is ignored on iOS")
+    }
+
     pub fn focus_window(&self) {
         warn!("`Window::set_focus` is ignored on iOS")
     }

src/platform_impl/linux/mod.rs

@@ -545,6 +545,9 @@ impl Window {
         x11_or_wayland!(match self; Window(w) => w.set_ime_purpose(purpose))
     }
 
+    #[inline]
+    pub fn set_ime_surrounding_text(&self, _text: String, _selection: (usize, usize)) {}
+
     #[inline]
     pub fn focus_window(&self) {
         match self {

src/platform_impl/macos/window.rs

@@ -1199,6 +1199,9 @@ impl WinitWindow {
     #[inline]
     pub fn set_ime_purpose(&self, _purpose: ImePurpose) {}
 
+    #[inline]
+    pub fn set_ime_surrounding_text(&self, _text: String, _selection: (usize, usize)) {}
+
     #[inline]
     pub fn focus_window(&self) {
         let is_minimized = self.isMiniaturized();

src/platform_impl/orbital/window.rs

@@ -333,6 +333,9 @@ impl Window {
     #[inline]
     pub fn set_ime_purpose(&self, _purpose: ImePurpose) {}
 
+    #[inline]
+    pub fn set_ime_surrounding_text(&self, _text: String, _selection: (usize, usize)) {}
+
     #[inline]
     pub fn focus_window(&self) {}
 

src/platform_impl/web/window.rs

@@ -366,6 +366,9 @@ impl Window {
         // Currently not implemented
     }
 
+    #[inline]
+    pub fn set_ime_surrounding_text(&self, _text: String, _selection: (usize, usize)) {}
+
     #[inline]
     pub fn focus_window(&self) {
         self.inner.dispatch(|inner| {

src/platform_impl/windows/window.rs

@@ -761,6 +761,9 @@ impl Window {
     #[inline]
     pub fn set_ime_purpose(&self, _purpose: ImePurpose) {}
 
+    #[inline]
+    pub fn set_ime_surrounding_text(&self, _text: String, _selection: (usize, usize)) {}
+
     #[inline]
     pub fn request_user_attention(&self, request_type: Option<UserAttentionType>) {
         let window = self.window.clone();

src/window.rs

@@ -1111,6 +1111,16 @@ impl Window {
         self.window.set_ime_purpose(purpose);
     }
 
+    /// Sets the surrounding text for IME.
+    ///
+    /// ## Platform-specific
+    /// - **Android**: should be set when a textfield is focused, so the keyboard has context
+    /// for autocomplete. If this is not set, the text will be cleared when the user starts typing.
+    /// - **iOS / Web / Windows / X11 / macOS / Orbital:** Unsupported.
+    pub fn set_ime_surrounding_text(&self, text: String, selection: (usize, usize)) {
+        self.window.set_ime_surrounding_text(text, selection);
+    }
+
     /// Brings the window to the front and sets input focus. Has no effect if the window is
     /// already in focus, minimized, or not visible.
     ///