PYsimpleGUI create a listbox of folders - user-interface

Question

I am trying to modify the demoprogram from PYsimpleGUI (Browser_START_HERE_Demo_program_Browser.py) to:
manually select a main folder
list all the subfolders in that folder (but not the files inside them)
make it possible to select a few of those folders, and list them as an output.
I thought I'd do so by editting the code for getting the file list dic, but everything I tried, just makes it
Any ideas? I attached it:
'''def get_file_list_dict():
"""
Returns dictionary of files
Key is short filename
Value is the full filename and path
:return: Dictionary of demo files
:rtype: Dict[str:str]
"""
demo_path = get_demo_path()
demo_files_dict = {}
for dirname, dirnames, filenames in os.walk(demo_path):
for filename in filenames:
if filename.endswith('.py') or filename.endswith('.pyw'):
fname_full = os.path.join(dirname, filename)
if filename not in demo_files_dict.keys():
demo_files_dict[filename] = fname_full
else:
# Allow up to 100 dupicated names. After that, give up
for i in range(1, 100):
new_filename = f'{filename}_{i}'
if new_filename not in demo_files_dict:
demo_files_dict[new_filename] = fname_full
break
return demo_files_dict'''

Answer 1

It's much difficult for me to modify code of Browser_START_HERE_Demo_program_Browser.py to my requirements.
Assume the target is
Select a main directory by a button to call function sg.popup_get_folder
List all subdirectories under main directory in one sg.Listbox
Subdirectories selected shown in another sg.Listbox as output when click Add button
Example Code
from pathlib import Path
import PySimpleGUI as sg
font = ("Courier New", 11)
sg.theme("Dark")
sg.set_options(font=font)
subfolders = []
selected = []
frame_subholders = [[sg.Listbox(subfolders, size=(80, 10), key='Subfolders',
select_mode=sg.LISTBOX_SELECT_MODE_EXTENDED, enable_events=True,
highlight_background_color='blue', highlight_text_color='white')]]
frame_selected = [[sg.Listbox(selected, size=(80, 10), key='Selected')]]
layout = [
[sg.Input(readonly=True, expand_x=True, key='Main',
disabled_readonly_background_color=sg.theme_input_background_color()),
sg.Button("Main Folder")],
[sg.Frame("Subholder", frame_subholders)],
[sg.Frame("Selected subholder", frame_selected)],
[sg.Button('Add')],
]
window = sg.Window('Title', layout, finalize=True)
entry = window['Main'].Widget
input_size = entry.winfo_width()//sg.Text.char_width_in_pixels(font)
print(input_size)
while True:
event, values = window.read()
if event == sg.WINDOW_CLOSED:
break
elif event == 'Main Folder':
main_folder = sg.popup_get_folder("", no_window=True)
if main_folder and Path(main_folder).is_dir():
main_folder = main_folder.replace("/", '\\') # For Windows
half = input_size//2
text = main_folder if len(main_folder) <= input_size else main_folder[:half-3]+"..."+main_folder[-half:]
window['Main'].update(text)
subfolders = sorted([str(f) for f in Path(main_folder).iterdir() if f.is_dir()])
window['Subfolders'].update(values=subfolders)
selected = []
window['Selected'].update(values=selected)
elif event == 'Add':
selected = sorted([path for path in values['Subfolders']])
window['Selected'].update(values=selected)
window.close()