Prefs class: singleton or something else?

[PatM]

Here's the singleton preferences class below

This is in a .py file by itselfs. I can't load it in one module then use it in all of them because it doesn't exist in any of the other .py files. I could put all of my classes into one big file then use the singleton a single time for use in all classes but I have a hard time finding anything when it's all one big file (that's why includes where invented right?).

This singleton is indeed the same in every instance but I can't seem to figure out a why to load the data from disk just once... Well, I could have the main program call the loading instead of doing it inside the prefs class itself but that is all I can think of.

Edit: Code snippet tag doesn't seem to work on this forum (or I just can't figure it out)

#Singleton Preferences

from PySide6.QtGui import QColor,QFont
from PySide6.QtCore import Qt
from os import path
from pubsub import pub
import json

class Preferences(object):
	def __new__(self):
		""" creates a singleton object, if it is not created,
		or else returns the previous singleton object"""
		if not hasattr(self, 'instance'):
			self.instance = super(Preferences, self).__new__(self)
		return self.instance


	def __init__(self):
		self._dict = None
#<Todo>
# Singleton Preferences
# figure out how to tell if it already exists so only loads once
#</Todo>
		if path.exists("prefs.json"):
			self.loadPrefs()
		else:
			self.setDefaults()

	def getFont(self):
		return QFont(self._dict["fontFamily"],self._dict["fontSize"])
	
	def setFontFamily(self,val):
		print(val)
		self._dict["fontFamily"] = val
	
	def getFontSize(self):
		return self._dict["fontSize"]
		
	def setFontSize(self,val):
		self._dict["fontSize"] = val
		
	def getFontColor(self):
		return QColor.fromString(self._dict["fontColor"])
	
	def setFontColor(self,val):
		self._dict["fontColor"] = val

	def getButtonWidth(self):
		return self._dict["buttonWidth"]
 
	def getButtonHeight(self):
		return self._dict["buttonHeight"]

	def showDict(self):
		print(self._dict)
		
	def setDefaults(self):
		self._dict = {
		"fontFamily":"None",
		"fontSize":16,
		"fontColor": "white",
		"buttonWidth":120,
		"buttonHeight":40
		}
		self.savePrefs()

	def loadPrefs(self):
		print("Loading singleton Preferences")
		with open('prefs.json', 'r') as openfile:
			self._dict = json.load(openfile)

	def savePrefs(self):
		self.showDict()
		print("Save singleton Prefs")
		_prefs = json.dumps(self._dict, indent=4)
		with open("prefs.json", "w") as outfile:
			outfile.write(_prefs)

Gribouillis write Dec-12-2022, 09:21 AM:
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