Class `Call __ instance as first argument error` Tkinter

Question

I am making a Tkinter text editor and I am having some trouble with classes. I have made a class with all my functions in it and a class with my mainloop. The root window opens up fine but when press the save button I get the error

Exception in Tkinter callback
Traceback (most recent call last):
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/lib-tk/Tkinter.py", line 1536, in __call__
    return self.func(*args)
TypeError: unbound method saveas() must be called with F instance as first argument (got nothing instead)

I have looked at this and this example but can't figure out what is going wrong. What is my problem?

Below is my short code that illustrates the problem.

from Tkinter import *
class Main(object):
    def __init__(self, root):
        root.title("PyText")
        self.m1=Menu(root)
        self.fm=Menu(self.m1, tearoff=0)
        self.fm.add_command(label="New", command=self.saveas())
        self.fm.add_command(label="Open", command=self.saveas())
        self.fm.add_command(label="Save", command=self.saveas())
        self.fm.add_command(label="Save as...", command=self.saveas())
        self.fm.add_command(label="Close", command=self.saveas())
        self.fm.add_separator()

        self.fm.add_command(label="Exit", command=root.quit)
        self.m1.add_cascade(label="File", menu=self.fm)
        self.editmenu = Menu(self.m1, tearoff=0)
        self.editmenu.add_command(label="Undo", command=self.saveas())

        self.editmenu.add_separator()

        self.editmenu.add_command(label="Cut", command=self.saveas())
        self.editmenu.add_command(label="Copy", command=self.saveas())
        self.editmenu.add_command(label="Paste", command=self.saveas())
        self.editmenu.add_command(label="Delete", command=self.saveas())
        self.editmenu.add_command(label="Select All", command=self.saveas())

        self.m1.add_cascade(label="Edit", menu=self.editmenu)
        self.helpmenu = Menu(self.m1, tearoff=0)
        self.helpmenu.add_command(label="Help Index", command=self.saveas())
        self.helpmenu.add_command(label="About...", command=self.saveas())
        self.m1.add_cascade(label="Help", menu=self.helpmenu)

        root.config(menu=self.m1)


        self.t1=Text(root)
        self.t1.config(width=90, height=40)
        self.t1.grid()
    def saveas(self):
        self.filewin = Toplevel()
        self.e1=Entry(self.filewin)
        self.e1.grid()
        self.button = Button(self.filewin, text="Save", command=self.save)
        self.button.grid()

    def save(self):
        with open(self.e1.get(), "w") as f: # this instance variable can be accessed
            f.write(self.t1.get('1.0', 'end')) # added self.t1 above, and start/end


root = Tk()
app = Main(root)
root.mainloop()

TigerhawkT3 · Accepted Answer · 2015-10-23 05:44:04Z

2

You're building your application wrong. Take the root Tkinter object-building code out of that class. You'll need a class that contains things for your Tkinter object. If you want more classes for other kinds of objects, that's fine. As it is, you're calling F.saveas as a class method with no argument, and it's expecting self, which is an instance of class F, which you don't have because you never instantiated it.

from Tkinter import *
class Main(object):
    def __init__(self, root):
        # root.geometry("100x100") # this will make your app window tiny -
        # I've commented it out for now but you'll need to look into it
        self.b1 = Button(root, text="save", command=self.saveas)
        self.b1.grid()
        self.t1 = Text(root) # added a Text widget
        self.t1.grid()
    def saveas(self):
        filewin = Toplevel()
        self.e1=Entry(filewin) # make this an instance variable
        self.e1.grid()
        button = Button(filewin, text="Save", command=self.save)
        button.grid()
    def save(self):
        with open(self.e1.get(), "w") as f: # this instance variable can be accessed
            f.write(self.t1.get('1.0', 'end')) # added self.t1 above, and start/end

master = Tk()
app = Main(master)
root.mainloop()

answered Oct 23, 2015 at 5:44

TigerhawkT3

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5 Comments

Jonah Fleming Over a year ago

I have edited my code now to include my full code because doing what you did created more errors.

TigerhawkT3 Over a year ago

@JonahFleming - What errors did you get with that? When I changed all the command=self.saveas() to command=self.saveas, it seemed to work fine.

Jonah Fleming Over a year ago

I'll try it but I got all of the menu items running their command at the start of the program.

TigerhawkT3 Over a year ago

@JonahFleming - That's why I changed all the command=self.saveas() to command=self.saveas as I said in my previous comment.

Jonah Fleming Over a year ago

Thanks that's been really useful +1

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