Obtain the project bucket for the valor

I have a question, is posible to obtain the project bucket for one valor in my data base?

I have this structure on my firebase DB and in App Inventor i have a variable with the value "run", so, i need to know for what user in my DB is saved this valor.

Actually i have a list of project bucket for do a list of the tags in likes:

  • datos/user1/likes
  • datos/user2/likes

The list of likes for all the list of project bucket results in:

  • run
  • eat
  • study

The second list is in a list view and on this, i need that when i choose any element in the list, this save the project bucket or the user for obtain this valor.

For example, if i select the element "run" in the listview, then It should show as response, the project bucket "datos/user1/likes" or the user "User1".

You have a choice:

  1. Call back all the data for a user, then extract the values for "run" in your app:

  2. Call back the values for "run" for a specific user

Thanks, but if i understand, in both situations I'll obtain values for an specific user that i choose. How can i get the user by the app?

Call back a taglist for "datos", this should give you a list of users: [user1,user2,user3]