How to retain state of selection in checkbox Tkinter, also how to add value and remove same value up-CodePudding

I'm writing a code which is having multiple dynamic checkboxes, my requirement is

To retain the selection of checkbox, in my current code, if I select another checkbox, first selection deselected automatically. in short I'm unable to maintain multiple checkbox checked
To get the value and add in a list when used selected checkboxes and remove same value when user deselected checkboxes. Currently what is happening is when I select the checkbox it added the correct value in list but when I deselect same checkbox, instead of remove that value, 0 is getting appended in list.

Below is the snippet of code I'm trying. Here eqpt_dict is a dictionary, so when user select the checkbox I want to add value of that key in a list and when user deselected the checkbox then want to remove same value from the list.

eqpt_dict = {'MDDDSERFEP1A': '10.5.30.110', 'MDDDSERFEP1B': 'x.x.x.x', 'MDDDSERFEP2A': 'x.x.x.x', 'MDDDSERFEP2B': 'x.x.x.x', 'TE02MSERFEPA': 'x.x.x.x', 'TE02MSERFEPB': 'x.x.x.x', 'TE03MSERFEPA': 'x.x.x.x', 'TE03MSERFEPB': 'x.x.x.x', 'TE05MSERFEPA': 'x.x.x.x', 'TE05MSERFEPB': 'x.x.x.x', 'TE06MSERFEPA': 'x.x.x.x', 'TE06MSERFEPB': 'x.x.x.x', 'TE09MSERFEPA': 'x.x.x.x', 'TE09MSERFEPB': 'x.x.x.x', 'TE10MSERFEPA': 'x.x.x.x', 'TE10MSERFEPB': 'x.x.x.x', 'TE14MSERFEPA': 'x.x.x.x', 'TE14MSERFEPB': 'x.x.x.x', 'TE17MSERFEPA': 'x.x.x.x', 'TE17MSERFEPB': 'x.x.x.x', 'TE19MSERFEPA': 'x.x.x.x', 'TE19MSERFEPB': 'x.x.x.x', 'TE22MSERFEPA': 'x.x.x.x', 'TE22MSERFEPB': 'x.x.x.x', 'selfServer': 'x.x.x.x'}
ip_list = list()
def checkbox_command():
    if var.get():
        if var.get() not in ip_list:
            ip_list.append(var.get())
    if not var.get():
        ip_list.remove(var.get())
    print(ip_list)

var = StringVar()
var.set('0')
for eqpt,ip in eqpt_dict.items():
    checkbutton4 = Checkbutton(text4, text=eqpt, variable=var, onvalue=ip,offvalue=0,bg='white', cursor="hand2",command=checkbox_command)
    checkbutton4.pack()

CodePudding user response：

Each checkbutton needs its own separate variable. When you do variable=var, you're assigning the same variable to every checkbutton, which means all checkbuttons will have the same value.

CodePudding user response：

In addition to Bryan Oakley's answer there is a problem with the logic in checkbox_command. var.get() returns the string '0' not the integer 0. This is Truthy and explains why unticking a box adds a '0' to the ip_list.

Below is code with a vars dictionary that holds the ticked/unticked state of the buttons. The checkbox_command then reads the state of all the button to create the latest version of ip_list

This is one of many possible approaches to the problem.

import tkinter as tk  # import as tk is safer and more flexible

root = tk.Tk()

eqpt_dict = {'MDDDSERFEP1A': '10.5.30.110', 'MDDDSERFEP1B': 'x.x.x.x', 
             'MDDDSERFEP2A': 'x.x.x.x',     'MDDDSERFEP2B': 'x.x.x.x', 
             'TE02MSERFEPA': 'x.x.x.x',     'TE02MSERFEPB': 'x.x.x.x', 
             'TE03MSERFEPA': 'x.x.x.x',     'TE03MSERFEPB': 'x.x.x.x', 
            }

ip_list = list()  # result list

def checkbox_command():
    """ Iterate through the vars dictionary and get the addresses from the 
        dictionary when the checkbox is set.
    """
    global ip_list

    # ip_list = [ eqpt_dict[ key] for key in eqpt_dict.keys() if vars[key].get() == 1 ]
    # List comprehension if you prefer.

    ip_list = []
    for key in eqpt_dict.keys():
        if vars[ key ].get() == 1:
            ip_list.append( eqpt_dict[ key ] )
    print( ip_list ) 

vars = {}   # A dict of vars.  Each checkbox needs it's own StringVar
            # The dictionary keeps the state of each Checkbox

for eqpt in eqpt_dict.keys():
    vars[ eqpt ] = tk.IntVar( value = 0 )
    checkbutton4 = tk.Checkbutton( root, text = eqpt, variable = vars[ eqpt ], 
        onvalue = 1, offvalue = 0, bg = 'white', cursor = "hand2",
        command = checkbox_command )
    checkbutton4.pack()

root.mainloop()