Very easy to reproduce.
1. Start from a new B4A and SDK installation.
2. Install B4A and install the standard checked items in the SDK manager from B4A.
3. Install Amir_Recyclerview and Amir_itempicker
4. Run the itempicker demo (in Amir_RecyclerView_FullPackage_1.0.5\Plugins\Amir_RVItemPicker\Sample 1)
You will get the following message:
java.lang.IndexOutOfBoundsException: Invalid item position 0(0). Item count:0 com.aghajari.rv.RecyclerView{28abdee3 VFED.... ......I. 0,0-0,0}, adapter:com.aghajari.rvplugins.Amir_RVItemPicker$Amir_RVItemPickerAdapter@35a940e0, layout:com.aghajari.rvplugins.PickerLayoutManager@38150f99, context:b4a.example.main@350e725e
If you look in Google, this seems to be a pretty common error linked to recent versions of the support library.
5. Delete the EXTRAS folder in the SDK, download the ZIP file at
https://www.dropbox.com/s/z8m46ak17i04rgq/Android_Support_SDK_ARV.rar?dl=0 and paste the contents in the EXTRAS folder. This ZIP contains an older version of the support library.
6. Run the example... it works!