Backends: SDL2: restore SDL_StartTextInput()/SDL_StopTextInput() calls on Android (#7636, #9474)

backends/imgui_impl_sdl2.cpp

@@ -21,6 +21,7 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
+//  2026-07-15: Inputs: restore SDL_StartTextInput()/SDL_StopTextInput() in IME handler for on-screen keyboard support on Android/mobile. (#7636, #9474)
 //  2026-04-16: Made ImGui_ImplSDL2_GetContentScaleForWindow(), ImGui_ImplSDL2_GetContentScaleForDisplay() helpers return a minimum of 1.0f, as some Linux setup seems to report <1.0f value and this breaks scaling border size. (#9369)
 //  2026-02-13: Inputs: systems other than X11 are back to starting mouse capture on mouse down (reverts 2025-02-26 change). Only X11 requires waiting for a drag by default (not ideal, but a better default for X11 users). Added ImGui_ImplSDL2_SetMouseCaptureMode() for X11 debugger users. (#3650, #6410, #9235)
 //  2026-01-15: Changed GetClipboardText() handler to return nullptr on error aka clipboard contents is not text. Consistent with other backends. (#9168)
@@ -205,6 +206,18 @@ static void ImGui_ImplSDL2_PlatformSetImeData(ImGuiContext*, ImGuiViewport*, ImG
         r.w = 1;
         r.h = (int)data->InputLineHeight;
         SDL_SetTextInputRect(&r);
+
+#ifdef __ANDROID__
+        // SDL_StartTextInput() is needed on Android (and some other platforms) to show the on-screen keyboard. (#7636, #9474, #6306)
+        // It was removed in a7703fe6 due to concerns about its relation to desktop IME, but is required on mobile.
+        SDL_StartTextInput();
+#endif
+    }
+    else
+    {
+#ifdef __ANDROID__
+        SDL_StopTextInput();
+#endif
     }
 }