Function which can be called to Prompt the user for a sub-folder, for example where asking for a folder within the Media folder, it can either be picked from the list or the Add button pressed to create a new folder within the selected one.

Requires: lfs

Code

function folderSelection(dir_path,sTreeTitle) local sDir = '' local function get_dir (dir_path)   local files = {}   local dirs = {}   for f in lfs.dir(dir_path) do     if f ~= '.' and f ~= '..' then       if lfs.attributes(dir_path..'\\'..f,'mode') == 'file' then         else         table.insert(dirs,f)       end     end   end   return files,dirs end       local tree = iup.tree {} tree.name = sTreeTitle tree.addexpanded = "NO"   local lbl_selected = iup.text { value = "\\", expand="HORIZONTAL",PADDING='5x5' }   local btn_ok = iup.button{ title = "OK",expand="HORIZONTAL", size='20x20',action=function() sDir=lbl_selected.value return iup.CLOSE end}    local function btn_add_action()     sFolder = lbl_selected.value     sPrompt = "Please select new Sub folder name for "..sFolder.."%t\nNew Sub Folder: %s\n"       ret, sName = iup.GetParam("Please select new Sub folder name for "..sFolder,     param_action,     sPrompt,     '',     0)	 print(ret)     if ret then	local sNewFolder = dir_path..sFolder..'\\'..sName     	lfs.mkdir(sNewFolder)	return true     end end   local btn_add = iup.button{ title = 'Add New Folder in "'..sTreeTitle..'" and select',expand="HORIZONTAL", size='20x20',action=function () if btn_add_action() then return iup.CLOSE end end} local function set (id,value,attrib)   iup.TreeSetUserId(tree,id,{value,attrib}) end   local function get(id)   return iup.TreeGetUserId(tree,id) end   local function fill (dir_path,id)   local files,dirs = get_dir(dir_path)   id = id + 1   local state = "STATE"..id     for i = #dirs,1,-1 do     tree.addbranch = dirs[i]     set(id,dir_path..'\\'..dirs[i],'dir')     tree['addleaf'..id] = "dummy" -- add a dummy node so branchopen_cb can be called   end end   function tree:selection_cb(id)	local t=get(id)  	if t then	  lbl_selected.value = t[1]:sub(dir_path:len() + 2)	btn_add.title = 'Add New Folder in "'..lbl_selected.value..'" and select'	else	  lbl_selected.value = '\\'	btn_add.title = 'Add New Folder in "'..sTreeTitle..'" and select'  	end end function tree:branchopen_cb(id)   tree.value = id   print(id)   local t = get(id)     if t and t[2] == 'dir' then     tree['delnode'..id+1] = 'selected' -- remove dummy     fill(t[1],id)     set(id,t[1],'xdir') -- mark branch as filled   end end     local dlg = iup.dialog{iup.vbox{	tree,	   iup.label({title='Please select the folder above and click OK',PADDING='5x5'}),	lbl_selected,	btn_ok,	iup.label({title='or use the button below to use a new sub folder',PADDING='5x5'}),	btn_add;MARGIN='5x5'	}; title = sTreeTitle.." Folder Selection";size='400x300'}   iup.SetHandle("main", dlg) dlg:map() fill(dir_path,0)   tree.STATE0 = 'EXPANDED' dlg:show()   if (iup.MainLoopLevel()==0) then iup.MainLoop() end	dlg:destroy()	return sDir end 

Can be called as follows:
Parameter 1: String the base folder
Parameter 2: String the short name for the folder selected, used as the tree title.

-- Require File system management require 'lfs'   local sFolder = folderSelection(fhGetContextInfo('CI_PROJECT_DATA_FOLDER')..'\\Media\\','Media') if sFolder   print(sFolder) else   print('aborted') end