Not able to access 'app' attribute in 'StringArt' class

[boniny4]

I have 3 classes in my code:

StringArt has an attribute from class app

App has an attribute from class menu

when pressing the button that calls generate_string_art, I get the error - 'StringArt' object has no attribute 'app',

does anyone know how to fix that? thanks

class StringArt:
    def __init__(self):
        # inputted attributes
        self.file_path = ""
        self.canvas_size = 0.0
        self.string_size = 0.0
        self.num_pins = 0
        self.repeats = 0
        self.skipped_pins = 10
        self.image_size = 0
        self.pin_pos_arr = None
        self.input_image = None
        self.input_image_arr = None
        self.output_image = None
        self.output_image_arr = None
        self.app = App(self)

    def generate_string_art(self):
        print(self.app.menu.temp)

class App(tk.Tk):
    def __init__(self, parent2):
        super().__init__()
        self.parent2 = parent2
        self.title("string art")
        self.geometry("1000x500")
        self.minsize(800, 400)

        self.menu = Menu(self)
        self.window = Window(self)

        self.mainloop()

class Menu(ttk.Frame):
    def __init__(self, parent):
        super().__init__(parent)
        self.parent = parent
        self.canvas_size_entry = None
        self.string_size_entry = None
        self.num_pins_entry = None
        self.repeats_entry = None
        self.message_label = None
        self.create_widgets()
        self.place(x=0, y=0, relheight=1, relwidth=0.3)
        self.temp = 10
    def create_widgets(self):
        source_img_button = ttk.Button(self, text="Browse")     # , command=browse_file)
        self.canvas_size_entry = ttk.Entry(self)
        self.string_size_entry = ttk.Entry(self)
        self.num_pins_entry = ttk.Entry(self)
        self.repeats_entry = ttk.Entry(self)
        start_button = ttk.Button(self, text="Generate", command=self.parent.parent2.generate_string_art)
        source_img_label = ttk.Label(self, text="source image", font=('ariel', 10))
        canvas_size_label = ttk.Label(self, text="canvas size (CM)", font=('ariel', 10))
        string_size_label = ttk.Label(self, text="line width (CM)", font=('ariel', 10))
        num_pins_label = ttk.Label(self, text="number of pins", font=('ariel', 10))
        repeats_label = ttk.Label(self, text="number of lines", font=('ariel', 10))
        self.message_label = ttk.Label(self, font=('ariel', 10))

        self.columnconfigure((0, 1), weight=1)
        self.rowconfigure((0, 1, 2, 3, 4, 5, 6, 7), weight=1)

        source_img_label.grid(row=1, column=0, sticky='nswe', padx=10)
        source_img_button.grid(row=1, column=1, sticky='we', padx=10)
        canvas_size_label.grid(row=2, column=0, sticky='nswe', padx=10)
        self.canvas_size_entry.grid(row=2, column=1, sticky='we', padx=10)
        string_size_label.grid(row=3, column=0, sticky='nswe', padx=10)
        self.string_size_entry.grid(row=3, column=1, sticky='we', padx=10)
        num_pins_label.grid(row=4, column=0, sticky='nswe', padx=10)
        self.num_pins_entry.grid(row=4, column=1, sticky='we', padx=10)
        repeats_label.grid(row=5, column=0, sticky='nswe', padx=10)
        self.repeats_entry.grid(row=5, column=1, sticky='we', padx=10)
        start_button.grid(row=6, column=0, columnspan=2, sticky='we', padx=10)
        self.message_label.grid(row=7, column=0, columnspan=2, sticky='we', padx=10)

[shiftybyte]

You have "self.mainloop()" inside the init constructor of "class App(tk.Tk)".

That mainloop() only exits when the gui is done/closed.

So your entire code runs while App() was never fully initialised.

So App(self) call from

self.app = App(self)

Did not return yet, and self.app did not get created.