Disable element of list picker for the next user

MIT App Inventor Help
1

Hello, I'm currently doing a simple reservation system. I have a list picker with elements of Slot 1 and Slot 2. A user is required to register and login to the system in order to make a reservation. For instance, if User A is already reserve Slot 1, is it possible to disable Slot 1 selection for User B? Meaning to say that User B cannot make a reservation on Slot 1 at the same time as User A. If possible, how can I do that?

Thanks in advance.

2

Hello Zuzu

  1. You could simply remove the reserved slots from the List.
  2. Or you could have a Static Blocks List of reserved slots, which the App can check before approving a reservation
  3. Or you could use an HTML List and have the reserved slots disabled (and shown in grey for example) - That requires a little bit of skill with HTML, CSS and Javascript.
4

As luck would have it, there is sample code on my website:

https://www.professorcad.co.uk/appinventorsnippets#DelListViewItems

5

A reservation system needs more than slot numbers to work.
It needs:

  • A calendar of time slots (e.e. 20200902) to define the time slot(s) of reservations
  • A list of reservable things (i.e. cars) identified uniquely (say by VIN or license number)
  • A list of possible reservers ("free"/ABG/Zuzu_N/...)
  • A data base of possible reservation statuses for key = combination time slot/thing, value = reserver

Setting up your database with this tag structure gives you direct access to the reservation status of each thing at each time.