Android Question dynamic array?

vecino · Nov 19, 2014

Hi, is it possible to do something like this?

B4X:

Sub aaaaa
  Dim aNumbers() As int
End Sub

Sub bbbbb
  Dim iAmount as int = DBconex.ExecQuerySingleResult("select count(id) from tbSome")
   
  aNumbers.SetLength( iAmount )        ' <--- Can you do something similar?
   
End Sub

JTmartins · Nov 19, 2014

Do you mean SetLenght as in Delphi ?

In that case you better use a List type, as it grows dinamicaly when you add itens to it and you do not need to care with array dimensions.

However, if your intention is just to use an array of fixed dimension, you can do something like

B4X:

Dim iAmount as int=DBconex.ExecQuerySingleResult("select count(id) from tbSome")

  Dim aNumbers( iAmount )

but ensure that iAmount is a valid value...You probably do not want to dimension an array with 0 elements

vecino · Nov 19, 2014

Thanks for your answer.

JTmartins said:
Do you mean SetLenght as in Delphi ?

Yes, exactly

JTmartins said:
In that case you better use a List type, as it grows dinamicaly when you add itens to it and you do not need to care with array dimensions.
However, if your intention is just to use an array of fixed dimension, you can do something like
but ensure that iAmount is a valid value...You probably do not want to dimension an array with 0 elements

The problem is that "aNumbers" is a public variable in another activity.

klaus · Nov 19, 2014

vecino said:
The problem is that "aNumbers" is a public variable in another activity.

Try Dim Main.aNumbers(iAmount) As Int

vecino · Nov 19, 2014

Sorry, is not another "activity", is a "code module"

LucaMs · Nov 19, 2014

Same.

~~MyModule.aNumbers(iAmount)~~

aNumbers should be declared as Public!

[P.S. no, it does not work.
You could use a List o a Map (better solution) or:

MyModule:

B4X:

Sub Process_Globals
    'These global variables will be declared once when the application starts.
    'These variables can be accessed from all modules.

    Public aNumbers() As Int
End Sub

Public Sub SetNumbersCount(N As Int)
    Dim aNumbers(N) As Int
End Sub

Elsewhere (activity):

B4X:

MyModule.SetNumbersCount(9)
MyModule.aNumbers(1) = 234
Log(MyModule.aNumbers(1))

vecino · Nov 19, 2014

Does that work?
I think it does not work
I made a test:

LucaMs · Nov 19, 2014

I think so too ^

LucaMs · Nov 19, 2014

The method I described works, but I strongly urge you to use a List instead of an array.

vecino · Nov 19, 2014

LucaMs said:

MyModule:

B4X:

Sub Process_Globals
    'These global variables will be declared once when the application starts.
    'These variables can be accessed from all modules.

    Public aNumbers() As Int
End Sub

Public Sub SetNumbersCount(N As Int)
    Dim aNumbers(N) As Int
End Sub

But in that code "aNumbers" are different variables, one public and one private.

DonManfred · Nov 19, 2014

You need to declare the variables in your globales-module. As public.
THEN you can use them in other modules or activities.
You can NOT dim new variables in globales from your activity... The dim must be in your module

LucaMs · Nov 19, 2014

vecino said:
But in that code "aNumbers" are different variables, one public and one private.

Try, it works.

But you should use a List or a Map (I prefer Maps; you can consider them as a kind of matrix, two-dimensional arrays, with the advantage of being able to identify each element by a name (or an object!), in addition to what I write below).

Using a List instead of an array of Int, you can:

B4X:

  Public lstNumbers As List : lstNumbers.Initialize

   ' "resize" the List automatically
   lstNumbers.Add(123)

   ' Insert a List (or array) inside the List
   Dim InsertAt As Int = 2
   lstNumbers.AddAllAt(InsertAt, Array As Int(1,2,3))

   ' Search for a value in the List (value can be an object)
   Dim IndexOf5 As Int = lstNumbers.IndexOf(5)

   ' Remove an element
   lstNumbers.RemoveAt(3)

   ' Set a value for an element
   lstNumbers.Set(2, 567)

   ' Sort the List
   lstNumbers.Sort(True)

Can you do all this with arrays?

vecino · Nov 20, 2014

Good idea, thank you very much

Android Question dynamic array?

vecino

Well-Known Member

JTmartins

Active Member

vecino

Well-Known Member

klaus

Expert

vecino

Well-Known Member

LucaMs

Expert

vecino

Well-Known Member

LucaMs

Expert

LucaMs

Expert

vecino

Well-Known Member

DonManfred

Expert

LucaMs

Expert

vecino

Well-Known Member

Similar Threads

Android Question dynamic array?

Well-Known Member

Active Member

Well-Known Member

Expert

Well-Known Member

Expert

Well-Known Member

Expert

Expert

Well-Known Member

Expert

Expert

Well-Known Member

Similar Threads

Privacy & Transparency

Privacy & Transparency