Since you cleared your onCreate () and assigned your initialization tasks to the workflow, the fact that your screen still remains dark for a while after starting your application is probably due to the complexity of the graphics in your initial (and not your initialization code, which is probably related to the model, not related to viewing).
The solution that you think worked for you is to use the visible background as the theme. I am glad that you found this adequate, but for some purposes a more specific (for example, application logo / name) screensaver (which quickly displays because it uses much simpler graphics) would be more desirable.
Please see the answer below for a detailed description (with sample code) of how to quickly display the splash screen:
Create a real screensaver
This also discusses the approach you took above.
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