Having a splash screen is redundant, and should be avoided unless maybe it’s the first run of the app. Users like to open the app and start using it right away.
Only really heavy apps (mostly games ) need to load a lot of things, but even there, there are plenty of optimizations to make it short (just load what it needs in the near future, for example).
Anyway, for the progress bar, just create a layout with a progress bar view in the middle, use “setContentView” on it, and that’s it…
You can also customize the progress bar by yourself, for example using this post.