Add Android window lifecycle support by Solessfir · Pull Request #108 · Try/Tempest

Solessfir · 2026-09-19T10:55:18Z

Adds the first Android runtime layer on top of the existing APK packaging helper.

Changes:

Add a SystemApi backend using NativeActivity, ANativeWindow and android_native_app_glue.
Forward window creation, destruction, resize, focus, pause and resume through Tempest events.
Stop rendering while the activity is inactive or has no native window.
Replace the stored native window handle when Android recreates the surface.
Convert the Android example to a normal Tempest Application and Window.

Vulkan surfaces, input, audio and other platform services are intentionally left for separate PRs.

Validated with:

ARM64 Android native build.
Debug APK assembly and Android lint.
APK inspection for lib/arm64-v8a/libtempest-example.so and the NativeActivity manifest.
Windows Debug build of Tempest.
Cold launch and background/resume on a Galaxy S24 (SM-S921B) running Android 16.

Try

Commented general stuff for now. Probably we would also need to refactor window initialization a bit

Try · 2026-09-19T15:15:37Z

+void AndroidApi::implSetWindowTitle(SystemApi::Window*, const char*) {
+  }
+
+int main(int argc, const char** argv);


You dont need to relay on static linking here.
dlopen(nullptr) + dlsym(..., "main") will get you function pointer to the main. And you allowed to always assume int(int, char** signature, since it's c-call.

Removed the static main declaration and switched to dlsym. On Android 16, dlopen(nullptr) cannot see the locally loaded NativeActivity library, so this locates the library containing android_main with dladdr and opens that before resolving main.

Try · 2026-09-19T15:44:07Z

+
+SystemApi::Window* createAndroidWindow(Tempest::Window* owner) {
+  if(mainWindow==nullptr)
+    mainWindow = new AndroidWindow();


SystemApi::Window* is expected to be something usable directly to swapchain. Similar to HWND on windows.
In case if android that would be ANativeWindow*.

Removed the wrapper. SystemApi::Window* is currently the ANativeWindow* itself. Replacing that pointer on surface recreation conflicts with the persistent Window::id contract, so that part remains unresolved in the later discussion: #108 (comment)

Try · 2026-09-19T15:45:47Z

+int AndroidApi::implExec(AppCallBack& cb) {
+  running = true;
+  while(running) {
+    pollAndroid(active && hasWindow ? 0 : -1);


pollAndroid is already part of implProcessEvents

Removed the duplicate polling from implExec. implProcessEvents owns normal event-loop polling. Initial window creation and activity shutdown also pump native events while waiting. In Solessfir@82fd004, an overlapping replacement activity pumps its own callbacks while waiting for the previous native session to finish, so Android's UI thread is not blocked.

Try · 2026-09-19T20:45:23Z

+
+class AndroidApi final : SystemApi {
+  public:
+    using SystemApi::dispatchClose;


Should not be public.

I've noticed, that you are using it from free-standing function onAppCmd. You can move onAppCmd -> AndroidApi::onAppCmd(void*, int32_t) instead. Similar to how windowProc is implemented, on windows.

Moved onAppCmd, focus and resize handling into private AndroidApi methods and removed the public dispatch aliases. A typed lambda bridges the native-app-glue callback to onAppCmd(void*, int32_t).

Try · 2026-09-19T20:54:24Z

+    return;
+
+  auto window = reinterpret_cast<SystemApi::Window*>(app->window);
+  AndroidApi::setWindowHandle(*mainWindow,window);


Window::id is expected to be persistent, and hot swapping should not be used.

I know, that this is general android issue, but engine has to have clean workaround and emulate same windowing as on any other platform.

I think, one option can be to spin-loop events in createAndroidWindow, unit APP_CMD_INIT_WINDOW or APP_CMD_DESTROY is met. APP_CMD_INIT_WINDOW = window created, all good. APP_CMD_DESTROY - exiting while creating window - return null (will be propagated to exception).

Correct me, if I'm wrong, but if AndroidManifest.xml (or activity) configured right way, then android wont sporadically kill the window, until the exit?

Moved the initial wait into createAndroidWindow.

Android can still destroy and recreate the drawing surface when switching apps. Could we keep a stable Tempest window handle and replace only the ANativeWindow stored inside it?

Vulkan would handle the surface change internally, so Window::id stays unchanged.

Try · 2026-09-19T20:55:42Z

+    }
+  }
+
+void pollAndroid(int timeout) {


no need to use namespace. For helper functions static is enough. static will hide your functions from linker.

Removed the anonymous namespace and made the file-local functions and state static.

Try · 2026-09-19T20:58:35Z

+  }
+
+SystemApi::Window* createAndroidWindow(Tempest::Window* owner) {
+  mainWindow = owner;


It looks like a general contract: only one window allowed at a time, on android. In this case, it's right to return null, if mainWindow is already initialized.

Added the guard: attempting to create a second window returns nullptr without changing the existing owner.

Try · 2026-09-19T21:00:51Z

+  }
+
+int AndroidApi::implExec(AppCallBack& cb) {
+  running.store(true);


nit:

int WindowsApi::implExec(AppCallBack& cb) { // main message loop while (!isExit.load()) { implProcessEvents(cb); } return 0; }

Swap running -> isExit would be nice for consistency.
Timers can be handled inside implProcessEvents

Changed running to atomic isExit and moved timer handling into implProcessEvents. Exit also wakes the looper, and event processing checks the exit flag before rendering or running timers.

Try · 2026-09-19T21:06:20Z

+
+  Dl_info module = {};
+  void* self = nullptr;
+  if(dladdr(reinterpret_cast<void*>(&android_main),&module)!=0)


probably this can be refactored away into separated function, and rewritten more clean with fail-fast approach (instead if multiple if-else)

Extracted entry-point lookup and invocation into runMain with early returns. android_main now handles exceptions and activity shutdown.

Added Android window lifecycle support

7d8c056

Try reviewed Sep 19, 2026

View reviewed changes

Addressed Android window review

2ee338f

Try reviewed Sep 19, 2026

View reviewed changes

Solessfir added 2 commits September 20, 2026 09:35

Simplified Android callbacks and window startup

beae5b2

Handle Android activity reopening

82fd004

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Solessfir commented Sep 19, 2026 •

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