CODEWITHSUNDEEP
python-3.xooptkinter
omrakn
omrakn

Reputation: 45

Calling button function from other class in tkinter

I want to create a button that uses a function (SaveFile) from other class but it throws TypeError. 

"TypeError: SaveFile() missing 1 required positional argument: 'self'"

My code is:

import tkinter as tk

class App1(tk.Frame):

    def __init__(self, parent, controller):
        tk.Frame.__init__(self, parent)
        tk.Button(self, text="Browse", command=self.SaveFile).grid(row=4, column=4)
        self.t1 = tk.Text(self, height=1, width=40, font="Times 9")
        self.t1.grid(row=2, column=3)

    def SaveFile(self):
        global name2
        name2 = asksaveasfilename(initialdir="\\", filetypes=(("Html Files", "*.html"),("All Files","*.*")),
                                  title = "Output path.")
        self.t1.delete("1.0", tk.END)
        self.t1.insert(tk.END, name2)

class App2(tk.Frame):

    def __init__(self, parent, controller):
        tk.Frame.__init__(self, parent) 
        self.b1 = tk.Button(self, text="Browse", command=App1.SaveFile)
        self.b1.grid(row=2, column=4)

Upvotes: 1

Views: 1240

Answers (1)

James Kent
James Kent

Reputation: 5933

ok for a more specific example:

import tkinter as tk

class App1(tk.Frame):

    def __init__(self, parent, controller):
        tk.Frame.__init__(self, parent)
        tk.Button(self, text="Browse", command=self.SaveFile).grid(row=4, column=4)
        self.t1 = tk.Text(self, height=1, width=40, font="Times 9")
        self.t1.grid(row=2, column=3)

    def SaveFile(self):
        global name2
        name2 = asksaveasfilename(initialdir="\\", filetypes=(("Html Files", "*.html"),("All Files","*.*")),
                                  title = "Output path.")
        self.t1.delete("1.0", tk.END)
        self.t1.insert(tk.END, name2)

class App2(tk.Frame):

    def __init__(self, parent, controller):
        tk.Frame.__init__(self, parent) 
        self.b1 = tk.Button(self, text="Browse", command=App1.SaveFile)
        self.b1.grid(row=2, column=4)

app1_inst = App1(parent, controller) # this creates an instance
app2_inst = App2(parent, controller) # this also creates an instance

App1.SaveFile # this is being called a class method, it is attached to the class so self does not get passed
app1_inst.SaveFile # is being called as an instance method where self = app1_inst

because app2_inst does not have any reference to app1_inst it cannot call it as an instance method. calling App1.SaveFile does not pass the instance in because it doesn't know if there even is an instance.

you need to change the definition of App2 to be able to pass in (and possible keep reference to) an instance of App1.

e.g. import tkinter as tk

class App1(tk.Frame):

    def __init__(self, parent, controller):
        tk.Frame.__init__(self, parent)
        tk.Button(self, text="Browse", command=self.SaveFile).grid(row=4, column=4)
        self.t1 = tk.Text(self, height=1, width=40, font="Times 9")
        self.t1.grid(row=2, column=3)

    def SaveFile(self):
        global name2
        name2 = asksaveasfilename(initialdir="\\", filetypes=(("Html Files", "*.html"),("All Files","*.*")),
                                  title = "Output path.")
        self.t1.delete("1.0", tk.END)
        self.t1.insert(tk.END, name2)

class App2(tk.Frame):

    def __init__(self, parent, controller, app1):
        tk.Frame.__init__(self, parent) 
        self.app1 = app1
        self.b1 = tk.Button(self, text="Browse", command=self.app1.SaveFile)
        self.b1.grid(row=2, column=4)

app1_inst = App1(parent, controller)
app2_inst = App2(parent, controller, app1_inst)

Upvotes: 3

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