androidandroid-ndknative-activity

APP_CMD_WINDOW_RESIZED is not called but native window is resized


I've native app, which is configured to not destroy activity on device orientation change.

<activity android:name="android.app.NativeActivity"
    ...
    android:configChanges="orientation|screenSize"
    ...
    >

When the devices orientation changes only following Native life-cycle command is triggered.

/**
 * Command from main thread: the current device configuration has changed.
 */
APP_CMD_CONFIG_CHANGED

In the command handler I can see that the window size has been changed with ANativeWindow_getHeight function.

(I know that ANativeWindow_getHeight function is not the best idea to use in config change handler to get the window size, I just only need to check if the window has been resized.)

If the native windows is resized I suppose following native command should be triggered ?

/**
 * Command from main thread: the current ANativeWindow has been resized.
 * Please redraw with its new size.
 */
APP_CMD_WINDOW_RESIZED

Why it has been blocked ?


Solution

  • Figured out the reason myself,

    The android native app glue does not have a code for firing APP_CMD_WINDOW_RESIZED command. But only has the definition for it.

    The reason for that, is because app glue code does not register the native callback onNativeWindowResized

    void ANativeActivity_onCreate(ANativeActivity* activity, 
                                 void* savedState, size_t savedStateSize) {
        LOGV("Creating: %p\n", activity);
        activity->callbacks->onDestroy = onDestroy;
        activity->callbacks->onStart = onStart;
        activity->callbacks->onResume = onResume;
        activity->callbacks->onSaveInstanceState = onSaveInstanceState;
        activity->callbacks->onPause = onPause;
        activity->callbacks->onStop = onStop;
        activity->callbacks->onConfigurationChanged = onConfigurationChanged;
        activity->callbacks->onLowMemory = onLowMemory;
        activity->callbacks->onWindowFocusChanged = onWindowFocusChanged;
        activity->callbacks->onNativeWindowCreated = onNativeWindowCreated;
        activity->callbacks->onNativeWindowDestroyed = onNativeWindowDestroyed;
        activity->callbacks->onInputQueueCreated = onInputQueueCreated;
        activity->callbacks->onInputQueueDestroyed = onInputQueueDestroyed;
        activity->instance = android_app_create(activity, savedState, savedStateSize); 
    }
    

    And finally the reason why it does not register for it is an android bug described here

    The documentation of native callbacks is here