Android Question XUI App

there are 2 learning videos about XUI
https://www.b4x.com/etp.html

simple explained xui is a replacement for accessing the native ui at different supported platforms.
if u see a library with B4X then it support more than one platform.

if you have more than one project you can share your class files.

xui or multi platform development have pros and cons, you will see.

You may have a look at the B4X XUI Booklet.

Be aware that you need one project for each platform.
Use as much as possible B4X Views which are wrappers above the original views.
You need the XUI libraries which are shiped with the products.
Use XUI Views, these are in the XUI Views B4XLibrary.
As already said, you can share modules between the projects, one file in one project and the other projects point to this file.

One cons, you may loose some platform specific views.
iOS and Android users may expect different interface layouts.

Truth is that there is no such thing as a XUI app. XUI is just a thin layer above the native views (and some other stuff) that provides cross platform APIs. Use XUI APIs when you can and use platform specific code when it is needed.