This is the best post I've seen on splash screens: http://saulmm.github.io/avoding-android-cold-starts
Saúl Molinero goes into two different options for splash screens: Taking advantage of the window background to animate into your initial screen and displaying placeholder UI (which is a popular choice that Google uses for most of their apps these days).
I refer to this post every time I need to consider cold start time and avoiding user dropoff due to long startup times.
Hope this helps!
