Android Question Assign List2 = List1 Links Them Forever?

[mmieher]

This surprised me. Is the Universe supposed to behave this way?

Log output:
** Activity (main) Create, isFirst = true **
List1.Size = 3
List2.Size = 3
AFTER List1.Clear then List2.Size = 0
** Activity (main) Resume **

Sub Activity_Create(FirstTime As Boolean)
    
    Dim List1 As List
    List1.Initialize
    
    List1.Add("Tom")
    List1.Add("Dick")
    List1.Add("Harry")
    Log("List1.Size = " & List1.Size)
    
    Dim List2 As List = List1
    Log("List2.Size = " & List2.Size)
    
    List1.Clear
    Log("AFTER List1.Clear then List2.Size = " & List2.Size)
    
End Sub

 

[Erel]

Yes.
Objects are passed by reference. This means that with this code both variables point to the same object.

If you want to duplicate the list:

Dim list2 As List
list2.Initialize
list2.AddAll(list1)

There are other more generic ways to duplicate (some types) of objects.

 

[LucaMs]

If you want to duplicate the list:

If I'm not mistaken, using AddAll the filled List becomes "invariable" (a sort of Array).


P.S.
No, I remembered badly.
That happens if you write something like:

List2 = Array As Int (1, 2, 3)

 

[Erel]

You are mistaken.

The case where you get a non-dynamic list is when you create a list that wraps an array:

Dim list1 As List = Array(1, 2, 3)
list1.Add(4) 'error
'note that List.Initialize2 behaves exactly the same as the above code

 

[LucaMs]

You are mistaken.

The case where you get a non-dynamic list is when you create a list that wraps an array:

Dim list1 As List = Array(1, 2, 3)
list1.Add(4) 'error
'note that List.Initialize2 behaves exactly the same as the above code

Yes, I had already corrected