This is a sample project to demonstrate how to expand or collapse the calendar and at the same time adjust a listview below it.
www.b4x.com
Make sure you have V2.07
[B4X] [XUI] AS CalendarAdvanced 📅 - OneRow/FiveRow Calendar - Expand and Collapse [Payware]
Hey all, after almost a week of work and much frustration, I am proud to share with you a calendar view. The view is inspired on the calendar view in the outlook app. This library is not free, because, it cost a lot of time and gray hair to create such views. Donations from 8€ are valid. (You...

Make sure you have V2.07
B4X:
Private Sub ASCalendarAdvanced1_HeightChanged(Height As Float)
'xpnl_main is a panel under the calendar with a xCLV in it
'same top a the calendar height
xpnl_main.Top = Height
xpnl_main.Height = Root.Height - Height
'height resize the xCLV
If xclv_main.AsView <> Null And xclv_main.AsView.IsInitialized = True Then
xclv_main.AsView.Height = xpnl_main.Height
xclv_main.Base_Resize(Root.Width,xpnl_main.Height)
End If
End Sub