Android Question Looking for fast way to identify Folders only

[GuyBooth]

I have a ListView where I list all the subfolders in a folder. First I create a list, and before loading them into the ListView I test to determine whether each entry is a Folder rather than a file. In most cases this works fine, but occasionally I hit a folder that has several thousand files in it. When this happens, the testing takes a long long time, because it has to test all the entries!
I can limit the total number of entries searched, as shown here, but it is possible that no folders would show up at all.

lstAllArray = File.ListFiles(edtPath.text)
' Sort the list
lstAllArray.Sort(True)
' Create a "real" lists. Limit the number of items counted to 75
' to avoid long periods with no apparent activity.
For i = 0 To Min(lstAllArray.Size - 1, 75)
     ' Create a proper list of just Folders
     If File.IsDirectory("", edtPath.text & "/" & lstAllArray.Get(i)) Then
            lstFolders.Add(lstAllArray.Get(i))
     End If       
Next

Would appreciate it if anyone can show me a way to list just the folders quickly, even in a folder that contains hundreds of files.

 

[DonManfred]

Use a thread to determine the folders if your code running to long

 

[GuyBooth]

Use a thread to determine the folders if your code running to long

Perhaps I need to clarify ...
This isn't a background task. The search starts when the user clicks on a button. He/she will be sitting waiting for the result.
Or have I misinterpreted your suggestion?

 

[DonManfred]

No.
There is no faster way... Checking a folder which contains a lot of files DO NEED some time

If you can strip it down a bit then maybe it´s faster.
Try to not use the check; instead only use folders without extension and only files WITH extension.
You then can check just the filenames coming from

File.ListFiles(edtPath.text)

instead of the need to look into the folder

 If File.IsDirectory(