Tags with Arrays

[OldVic]

:sign0085:When I attempt to change a tag in one object it changes ALL the tags in the card array -

Sub Globals
'These global variables will be redeclared each time the activity is created.
'These variables can only be accessed from this module.
Dim c0,c1,c2,c3 As ImageView
Dim CardViews() As ImageView
Dim Comments As Label
Type TagData(Who As Int,Where As String)
Dim MyTag As TagData
End Sub

Sub Activity_Create(FirstTime As Boolean)
Dim i,j As Int
Dim q As String
'Dim MyTag As TagData
activity.LoadLayout("test4")
CardViews=Array As ImageView(c0,c1,c2,c3)
For i=0 To 3 'Sets all lower arrays in addition to current one!!!
q="KK"
MyTag.Who=i
MyTag.Where=q
CardViews(i).Tag=MyTag
j=i
Next
Comments.Text=Comments.Text & "1="
Printit

MyTag=CardViews(2).Tag 'makes all tags the same!!!
MyTag.Who=5
CardViews(2).Tag=MyTag
Comments.Text=Comments.Text & " 2="
Printit

' For i=0 To 3
' j=5+i
' MyTag=CardViews(i).Tag
' MyTag.Who=j
' MyTag.Where="NN"
' CardViews(i).Tag=MyTag 'Stops here when assembling
' Next i
' Comments.Text=Comments.Text & " 2="
' Printit
' For i=3 To 0 Step -1
' j=5+1
' MyTag.Who=i
' MyTag.Where=q
' CardViews(i).Tag=MyTag
' Next i
' Comments.Text=Comments.Text & " 2="
' Printit
End Sub
Sub Printit
Dim i As Int
' Dim MyTag As TagData
For i=0 To 3
MyTag =CardViews(i).tag
Comments.Text=Comments.Text & " Who=" &MyTag.Who
Next
End Sub

The first change prints "3 3 3 3" instead of "0 1 2 3" and the second change prints "5 5 5 5".
Also, the commented-out block won't assemble. It stops on line 42. What's going on?

 

[Erel]

You are adding the same object multiple times to the array. See this tutorial: http://www.b4x.com/forum/basic4andr...als/8385-variables-objects-basic4android.html
This issue is discussed there.

 

[OldVic]

Tags and arrays

Thanks, but I still don't see where I'm adding another tag to each object. Redimensioning before each change doesn't work. As soon as I do "CardViews(2).Tag=MyTag" all objects in the array get the same tag. What is the correct code to use?

 

[Erel]

The problem with your code is that you are creating a single MyTag object and then add it multiple times. You are actually adding a reference to the same object again and again.
To fix it you should declare MyTag as a local variable and Dim it inside the loop. Then you will get a new object every iteration.