Texteditor-GUI-Menu

from guizero import App, TextBox, PushButton, Box, Combo, Slider, MenuBar

app = App(title="text editor")

# function for reading files
def open_file():
    with open(file_name.value, "r") as f:
        editor.value = f.read()
    #disable save button till edited
    save_button.hide()
    file_name.show()

# function for writing files
def save_file():
    with open(file_name.value, "w") as f:
        f.write(editor.value)
    #disable save button till edited
    save_button.hide()
    file_name.show()

# function for changing font style
def change_font():
    editor.font = font.value

#function for changing text size
def change_text_size():
    editor.text_size = size.value
    #reset box size to adjust to new text size
    editor.resize(1,1)
    editor.resize("fill", "fill")

#function for changing text colour
def change_color():
    editor.text_color = colour.value

#function to re-anable save button
def save_enable():
    save_button.show()

#function that reveals file name after initializing as hidden
def name_show():
    file_name.show()

#function that revealsthe file controls
def file_controls_show():
    file_controls.show()

#function that reveals the text preferences
def text_preferences_show():
    text_preferences.show()

#function that exits the app
def exit_app():
    app.destroy()

#Main menubar
menubar = MenuBar(app, toplevel = ["File", "Edit"], options = [[["Open", file_controls_show], ["Save", file_controls_show], ["Exit", exit_app]], [["Font", text_preferences_show], ["Size", text_preferences_show], ["Colour", text_preferences_show]]])

# create a box to house the controls, we want the box to span the entire width of the app
file_controls = Box(app, align="top", width="fill", border = True, visible = False)

#Create a new box to house text preferences
text_preferences = Box(app, align = "top", width = "fill", border = True, visible = False)
font = Combo(text_preferences, align = "left", options = ["courier", "helvetica", "times new roman", "verdana"], command = change_font)
size = Slider(text_preferences, align = "left", command = change_text_size, start = 10, end = 24)
colour = Combo(text_preferences, align = "left", command = change_color, options = ["black", "red", "blue", "green"])

# create an open button which uses the open_file function
open_button = PushButton(file_controls, text="Open",  align="left", command = open_file)

#create a button to create a new file
new_button = PushButton(file_controls, text = "New", align = "left", command = name_show)

# create a TextBox for the file name
file_name = TextBox(file_controls, text="text_file.txt", width=20, align="left", visible = False)

# create a save button which uses the save_file function
save_button = PushButton(file_controls, text="Save",  align="right", command = save_file)

# create a TextBox which is not in the box and fills the rest of the GUI
editor = TextBox(app, multiline=True, height="fill", width="fill", command = save_enable)

app.display()