Use android-activity's show_soft_input to summon the keyboard.

src/changelog/unreleased.md

@@ -59,6 +59,7 @@ changelog entry.
 - Implement `Clone`, `Copy`, `Debug`, `Deserialize`, `Eq`, `Hash`, `Ord`, `PartialEq`, `PartialOrd`
   and `Serialize` on many types.
 - Add `MonitorHandle::current_video_mode()`.
+- On Android, the soft keyboard can now be shown using `Window::set_ime_allowed`.
 - Add basic iOS IME support. The soft keyboard can now be shown using `Window::set_ime_allowed`.
 - Add `ApplicationHandlerExtMacOS` trait, and a `macos_handler` method to `ApplicationHandler` which returns a `dyn ApplicationHandlerExtMacOS` which allows for macOS specific extensions to winit.
 - Add a `standard_key_binding` method to the `ApplicationHandlerExtMacOS` trait. This allows handling of standard keybindings such as "go to end of line" on macOS.

src/platform_impl/android/mod.rs

@@ -925,7 +925,13 @@ impl CoreWindow for Window {
 
     fn set_ime_cursor_area(&self, _position: Position, _size: Size) {}
 
-    fn set_ime_allowed(&self, _allowed: bool) {}
+    fn set_ime_allowed(&self, allowed: bool) {
+        if allowed {
+            self.app.show_soft_input(true);
+        } else {
+            self.app.hide_soft_input(true);
+        }
+    }
 
     fn set_ime_purpose(&self, _purpose: ImePurpose) {}