What does RemoveView(at) Do?

[SeaCay]

Hello All,

I was wondering what does RemoveView or RemoveViewAt actually do.

The wiki says
"Removes this view from its parent."

I am aware that the nominated view disappears. But it crossed my mind at to whether the views are deleted from memory or can the views be-instantiated?

Further thoughts were if the view was only hidden, and I no longer need the view, do I need to perform any memory management/garbage collection to prevent memory leaks or is there no concern of this nature at all?

Thanks for your help on this question

regards

SeaCay

 

[Theera]

Hi,
Try this code below
Sub RemoveAllViews
Dim I As Int
For I = Activity.NumberOfViews - 1 To 0 Step -1
Activity.RemoveViewAt(I)
Next
End Sub
Best Regards
Theera

 

[margret]

If you use RemoveView:

The Views are removed and sent to the collector. The OS will clear the memory when needed.

You do not need to perform anything further. If you wish to use the view again you will have to redefine the view, creating a new view.

 

[agraham]

That's not entirely true. RemoveView removes a View from the ViewGroup of its parent and that is all. The View is only collected by the GC if no further references to it exist. You can keep a reference to a removed View in a variable and add it back to another (or the same) Panel or Activity without having to reinstantiate it.

 

[warwound]

You can keep a reference to a removed View in a variable and add it back to another (or the same) Panel or Activity without having to reinstantiate it.

You cant' keep a reference to a View and use the same instance of that View in another Activity i thought?

Aren't Views created with the Context of the Activity that calls their constructor?

Martin.

 

[agraham]

and add it back to another (or the same) Panel or <clarify>the same </clarify>Activity without having to reinstantiate it.

 

[margret]

If you have the code below. Once you click Button1, what else is required for the collector to recover the memory used by this Panel?

Sub Globals
   Dim ab As Panel
   ab.Initialize("ab")
   Activity.AddView(ab, 10, 10, 1000, 500)
   ab.Color = Colors.Red
End Sub

Sub Button1_Click
   ab.RemoveView
End Sub

 

[agraham]

ab = null

 

[margret]

@agraham,

I ran a test on this and just like you said, you can add it back to another panel, etc.

Awesome, thanks for the information and clarification on this subject. It's great to learn something new!!

 

[SeaCay]

Thanks everyone.

I appreciate your replies.

regards

SeaCay

 

[EduardoElias]

I am using an example i got in the forum to implement a grid, adding labels to a scrollview.

I fill the scrollview with rows that are labels. That works fine.

When i need to save my list, i go thru all the labels to create a list to save. I do not keep references to this labels or data in a separated list.

After saving I go over the list to delete it using this code:

'Clears the table
For i = svList.Panel.NumberOfViews -1 To 0 Step -1
svList.Panel.RemoveViewAt(i)
Next

however I found that besides the view disappears (the labels are gone from the scrollview) next time that i recreate the grid list with other items, when is the moment to save again, i go thru the list and i get the current labels, and all past ones.

That means that besides RemoveViewAt remove the label it is being kept on the list and are accessible on the panel list of views.

What is happening? Maybe i am not understanding something else.

Thanks,

 

[Erel]

RemoveViewAt removes the view from the panel. If there are other references to that view (from a different list for example) then those references will still be valid.

I recommend you to use CustomListView class or CheckList class instead of implementing a similar solution.