Android Question Need help with for loop

For i = 0 to (items.Size/20)-1
    For j = 0 to 19
         Stuff(items.Get(i*20+j))
    Next
Next

    Dim k As Int
    Dim n As Int = items.Size - 1
    For i = 0 To n Step 20       ' step each 20
        k = i + 19
       
        ' check if we're nearing the end to prevent out of bounds errors
        If k >= n Then k = n - i
       
        For j = 0 To k
            Stuff(items.Get(i + j)
        Next
    Next

lv.Clear
    Dim pm As PackageManager
    Dim packages As List
    packages = pm.GetInstalledPackages
   
   Dim k As Int
  Dim n As Int = packages.Size- 1
  For i = 0 To n Step 20  ' step each 20
  k = i + 19
   
  ' check if we're nearing the end to prevent out of bounds errors
   
  If k >= n Then k = n - i
  For j = 0 To k
    Dim p As String = packages.Get(i)
        Dim bdw As BitmapDrawable = pm.GetApplicationIcon(p)
        lv.AddTwoLinesAndBitmap(pm.GetApplicationLabel(p),packages.Get(i),bdw.Bitmap)

    Next
Next

Dim p as String = packages.Get(i)
...
lv.AddTwoLinesAndBitmap(pm.GetApplicationLabel(p),packages.Get(i),bdw.Bitmap)

Dim p as String = packages.Get(i+j)
...
lv.AddTwoLinesAndBitmap(pm.GetApplicationLabel(p),packages.Get(i+j),bdw.Bitmap)

k = i + 19

k = 19

If k >= n then k = n - i

If k+i >= n then k = n - i