Run code before unity initialization in Android

I want to run some code before unity initialization in Android to check for internet connectivity. If no internet connection is available, I want unity not to get initialized. I can't do that by extending UnityPlayerNativeActivity, because I have no way to stop onCreate from calling. I therefore tried to create my one launch activity, which then initiates UnityPlayerProxyActivity. Is this the right way to go? Will it break anything, if I replace the launch activity?