App UI Layout as Splash Screen
Adam Navarro
The Splash Screen API should allow developers to use complex configs such as an Interface Builder file so that a splash screen can look like a skeleton of the app's main UI (as seen with Instagram). Related github issue: https://github.com/expo/expo/issues/822
Chrıs Seelus
Yeah, that’s what the Human Interface Guidelines recommend, so opening or switching to a suspended app feels like the interface is rendered instantaneously.
Afaik this can only be done with an Interface Builder file to cater to all the different screen sizes.