Initial settings demo program check-in

DemoPrograms/Demo_Settings_Save_Load.py

@@ -0,0 +1,98 @@
+import PySimpleGUI as sg
+from json import (load as jsonload, dump as jsondump)
+from os import path
+
+"""
+    A simple "settings" implementation.  Load/Edit/Save settings for your programs
+    Uses json file format which makes it trivial to integrate into a Python program.  If you can
+    put your data into a dictionary, you can save it as a settings file.
+    
+    Note that it attempts to use a lookup dictionary to convert from the settings file to keys used in 
+    your settings window.  Some element's "update" methods may not work correctly for some elements.
+    
+    Copyright 2020 PySimpleGUI.com
+    Licensed under LGPL-3
+"""
+
+SETTINGS_FILE = path.join(path.dirname(__file__), r'settings_file.cfg')
+DEFAULT_SETTINGS = {'max_users': 10, 'user_data_folder': None , 'theme': sg.theme(), 'zipcode' : '94102'}
+# "Map" from the settings dictionary keys to the window's element keys
+SETTINGS_KEYS_TO_ELEMENT_KEYS = {'max_users': '-MAX USERS-', 'user_data_folder': '-USER FOLDER-' , 'theme': '-THEME-', 'zipcode' : '-ZIPCODE-'}
+
+########################################## Load/Save Settings File ##########################################
+def load_settings(settings_file, default_settings):
+    try:
+        with open(settings_file, 'r') as f:
+            settings = jsonload(f)
+    except Exception as e:
+        sg.popup_quick_message(f'exception {e}', 'No settings file found... will create one for you', keep_on_top=True, background_color='red', text_color='white')
+        settings = default_settings
+        save_settings(settings_file, settings, None)
+    return settings
+
+
+def save_settings(settings_file, settings, values):
+    if values:      # if there are stuff specified by another window, fill in those values
+        for key in SETTINGS_KEYS_TO_ELEMENT_KEYS:  # update window with the values read from settings file
+            try:
+                settings[key] = values[SETTINGS_KEYS_TO_ELEMENT_KEYS[key]]
+            except Exception as e:
+                print(f'Problem updating settings from window values. Key = {key}')
+
+    with open(settings_file, 'w') as f:
+        jsondump(settings, f)
+
+    sg.popup('Settings saved')
+
+########################################## Make a settings window ##########################################
+def create_settings_window(settings):
+    sg.theme(settings['theme'])
+
+    def TextLabel(text): return sg.Text(text+':', justification='r', size=(15,1))
+
+    layout = [  [sg.Text('Settings', font='Any 15')],
+                [TextLabel('Max Users'), sg.Input(key='-MAX USERS-')],
+                [TextLabel('User Folder'),sg.Input(key='-USER FOLDER-'), sg.FolderBrowse(target='-USER FOLDER-')],
+                [TextLabel('Zipcode'),sg.Input(key='-ZIPCODE-')],
+                [TextLabel('Theme'),sg.Combo(sg.theme_list(), size=(20, 20), key='-THEME-')],
+                [sg.Button('Save'), sg.Button('Exit')]  ]
+
+    window = sg.Window('Settings', layout, keep_on_top=True, finalize=True)
+
+    for key in SETTINGS_KEYS_TO_ELEMENT_KEYS:   # update window with the values read from settings file
+        try:
+            window[SETTINGS_KEYS_TO_ELEMENT_KEYS[key]].update(value=settings[key])
+        except Exception as e:
+            print(f'Problem updating PySimpleGUI window from settings. Key = {key}')
+
+    return window
+
+########################################## Main Program Window & Event Loop ##########################################
+def create_main_window(settings):
+    sg.theme(settings['theme'])
+
+    layout = [[sg.T('This is my main application')],
+              [sg.T('Add your primary window stuff in here')],
+              [sg.B('Ok'), sg.B('Exit'), sg.B('Change Settings')]]
+
+    return sg.Window('Main Application', layout)
+
+
+def main():
+    window, settings = None, load_settings(SETTINGS_FILE, DEFAULT_SETTINGS )
+
+    while True:             # Event Loop
+        if window is None:
+            window = create_main_window(settings)
+
+        event, values = window.read()
+        if event in (None, 'Exit'):
+            break
+        if event == 'Change Settings':
+            event, values = create_settings_window(settings).read(close=True)
+            if event == 'Save':
+                window.close()
+                window = None
+                save_settings(SETTINGS_FILE, settings, values)
+    window.close()
+main()