IssueTracker

For starters, there is a bug in android_native_app_glue.c.

In android_main, when calling GameActivity_finish(pAndroidApp->activity) the game correctly exits. However, when resuming the game, we end up in the onPause callback even though android_app->destroyed is set:

static void android_app_set_activity_state(struct android_app* android_app,
                                           int8_t cmd) {
    pthread_mutex_lock(&android_app->mutex);
    android_app_write_cmd(android_app, cmd);
    while (android_app->activityState != cmd) {
        pthread_cond_wait(&android_app->cond, &android_app->mutex); // Deadlock? Waits forever...
    }
    pthread_mutex_unlock(&android_app->mutex);
}

When we get here, the android_app struct contains these relevant values:

onAppCmd       NULL
msgread        115
msgwrite       116
activityState  12
running        1
destroyed      1

Additional notes. In GameActivity class, the GameActivity_finish() call makes us hang in onPause():

protected void onPause() {
    super.onPause();
    this.onPauseNative(this.mNativeHandle); // Hangs here!
}

So we try to finish the activity, but it resumes and then pauses. Really odd! The docs tell us otherwise:

Its finish() method will be called, causing it to be stopped and destroyed.

Apparently, some integrations out there have patched this locally. E.g. See this PR: https://github.com/rust-mobile/android-activity/pull/94

Most of us are using prefab though, so we cannot patch the glue code...

I created a sample project demonstrating the deadlock. Just run it from Android Studio, and it will immediately hang in GameActivity.OnPause().

If you check your Google Play logs, you will probably find some million crashes related to this. It's easy to reproduce, and I have observed similar crashes in many popular games out there. I.e. You leave the game, you return to it many hours later, it crashes after a second or so, you restart it and it works.

Many engines out there are adopting GameActivity. Please provide a fix or workaround.