diff --git a/src/anbox/platform/sdl/platform.cpp b/src/anbox/platform/sdl/platform.cpp
index 05128a171ea0d35c4dad3a0c742f9655e8cced5f..9594935035566c27de80f0bbcdd550b9fe2b3e2c 100644
--- a/src/anbox/platform/sdl/platform.cpp
+++ b/src/anbox/platform/sdl/platform.cpp
@@ -391,6 +391,12 @@ void Platform::process_input_event(const SDL_Event &event) {
         input_key_event(SDL_SCANCODE_AC_BACK, 0);
         break;
       }
+      if (code == KEY_CAPSLOCK) {
+        key_mod_ ^= KMOD_CAPS;
+      }
+      if (code == KEY_NUMLOCK) {
+        key_mod_ ^= KMOD_NUM;
+      }
       keyboard_events.push_back({EV_KEY, code, 0});
       break;
     }
@@ -574,7 +580,23 @@ void Platform::window_deleted(const Window::Id &id) {
 
 void Platform::window_wants_focus(const Window::Id &id) {
   auto w = windows_.find(id);
-  if (w == windows_.end()) return;
+  if (w == windows_.end()) {
+    return;
+  }
+
+  // if window's modstate is not the same as android, send
+  // capslock or numlock message to android to change it.
+  auto mod_state = SDL_GetModState();
+  if ((key_mod_ & KMOD_NUM) != (mod_state & KMOD_NUM)) {
+    input_key_event(SDL_SCANCODE_NUMLOCKCLEAR, 1);
+    input_key_event(SDL_SCANCODE_NUMLOCKCLEAR, 0);
+    key_mod_ ^= KMOD_NUM;
+  }
+  if ((key_mod_ & KMOD_CAPS) != (mod_state & KMOD_CAPS)) {
+    input_key_event(SDL_SCANCODE_CAPSLOCK, 1);
+    input_key_event(SDL_SCANCODE_CAPSLOCK, 0);
+    key_mod_ ^= KMOD_CAPS;
+  }
 
   if (auto window = w->second.lock()) {
     focused_sdl_window_id_ = window->window_id();
diff --git a/src/anbox/platform/sdl/platform.h b/src/anbox/platform/sdl/platform.h
index 6294d59021df2c1c0cea4f17887aa6adeff79eed..9b8af4cd7e1f709b86993da74b891598e5992f67 100644
--- a/src/anbox/platform/sdl/platform.h
+++ b/src/anbox/platform/sdl/platform.h
@@ -125,6 +125,7 @@ class Platform : public std::enable_shared_from_this<Platform>,
   void push_finger_motion(int x, int y, int finger_id, std::vector<input::Event> &touch_events);
 
   int user_window_event = 0;
+  std::uint32_t key_mod_{ KMOD_NONE };
 };
 } // namespace sdl
 } // namespace platform
diff --git a/src/anbox/platform/sdl/window.cpp b/src/anbox/platform/sdl/window.cpp
index e945faa36659dd34092778e3fdd20d1912819be1..0ade5a63b491a2dc5fc172c5939cd078e281d4fa 100755
--- a/src/anbox/platform/sdl/window.cpp
+++ b/src/anbox/platform/sdl/window.cpp
@@ -57,7 +57,7 @@ const std::map<std::string, Window::mini_size>Window::custom_window_map = {
   {"微信", {WX_MINI_WIDTH, MINI_HEIGHT}}
 };
 
-Window::Id Window::Invalid{-1};
+Window::Id Window::Invalid{ -1 };
 
 Window::Observer::~Observer() {}
 
@@ -294,7 +294,9 @@ void Window::switch_window_state() {
 void Window::process_event(const SDL_Event &event) {
   switch (event.window.event) {
     case SDL_WINDOWEVENT_FOCUS_GAINED:
-      if (observer_) observer_->window_wants_focus(id_);
+      if (observer_) {
+        observer_->window_wants_focus(id_);
+      }
       break;
     case SDL_WINDOWEVENT_FOCUS_LOST:
       break;