How can I disable the the button? (GUI)

user_16055650 0
Viewed 69

I'm making simple calculator and I've implemented all the functions except one function. As you know, dots must be used only once until the new number comes. So I want to make the (.) button disabled after used once and make it available again when I use symbol or C. I was thinking about changing the button text by using configure method.

Here's my code:

from tkinter import*
w1 = Tk()
w1.title("My Calculator") 
show = Entry(w1, width=33, bg="yellow") 
show.grid(row=0, column=0, columnspan=5)
btn_list = [ 
    '7','8','9','/','C',
    '4','5','6','*','',
    '1','2','3','-','',
    '0','.','=','+','']
index_row = 1 
index_col = 0 
def click(button): 
    if button == "=":  
        value = eval(show.get()) 
        s = str(value) 
        show.delete(0,"end") 
        show.insert(END,s) 
    elif button=="C": 
        show.delete(0,"end") 
    else: 
        show.insert(END,button) 
for btn_text in btn_list: 
    def go(k=btn_text): 
        click(k)
    Button(
        w1, text=btn_text, width=5, command=go
    ).grid(row=index_row, column=index_col) 
    index_col += 1 
    if index_col > 4: 
        index_row += 1  
        index_col = 0

w1.mainloop()
tkinter python
1 Answers

Easiest way is to use a tkinter variable and trace it.

var = StringVar()
show = Entry(w1, width=33, bg="yellow", textvariable=var) 

def validate(*args):
    if var.get().count('.') > 1:
        var.set(var.get()[:-1])

var.trace('w',validate)

There are more than just one way to do this, starting with storing input in the list, or storing the specific button as a variable and so on. There are also different ways to loop through the texts easily.

Updated because your professor has not taught you the previous method(yet):

def click(button): 
    ..... # Same stuff

    if show.get().count('.') >= 1:
        dot_btn.config(state='disabled')
    else:
        dot_btn.config(state='normal')

for btn_text in btn_list: 
    def go(k=btn_text): 
        click(k)
    if btn_text == '.':
        dot_btn = Button(w1, text=btn_text, width=5, command=go)
        dot_btn.grid(row=index_row, column=index_col) 
    else:
        Button(
            w1, text=btn_text, width=5, command=go
        ).grid(row=index_row, column=index_col) 
    index_col += 1 
    if index_col > 4: 
        index_row += 1  
        index_col = 0

This looping method is really beating around the bush, directly you could just use nested loops and get your desired output, you would not even need to made index_row and index_col. Never limit your understanding to what your professor or mentor has taught you, be ready to explore and learn more(maybe you will end up teaching him :P).

Note that using eval() to do mathematical expressions alone is poor, it opens a whole new galaxy of security issues.

user_133820000
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