如何使用Tkinter和函数找到选中的复选按钮？

Question

在这里，我试图创建一个三种水果的列表，苹果、石榴和香蕉，并要求用户选择他们最喜欢的水果。因此，我定义了一个函数print_choice，每次选中任何复选框时都会调用它，并定义了一个数组fruits，当选中复选框时，它会将相应的结果附加到数组中。 我在函数中定义了数组，而不是全局声明，因为值不应该添加两次。但是，我无法在标签框中打印选择，该标签框应显示用户选择的水果列表。你能帮我找出哪里出了错，我怎样才能显示所选的水果吗

 import tkinter as tk
from tkinter import *

parent = tk.Tk()
parent.title("My favorite fruits")
l= tk.Label(parent, background="yellow", text="empty", width="30")
l.pack()
w = tk.Label(parent , text ="Select your favorite fruits!", bg="pink", fg = "white")

txt = "you love "
def print_choice():
    fruits=list()
    global txt
    flag=0
    while flag==0:
         if checkvar1.get()==1 and checkvar2.get==0 and checkvar3.get()==0:
             fruits.append("Apple")
             flag=1
             break
         elif checkvar2.get()==1 and checkvar1.get()==0 and checkvar3.get()==0:
             fruits.append("Pomegranate")
             flag=1
             break
         elif checkvar3.get()==1 and checkvar1.get()==0 and checkvar2.get()==0:
             fruits.append("Banana")
             flag=1
             break
         elif checkvar3.get()==1 and checkvar1.get()==1 and checkvar2.get()==0:
             fruits.append("Banana")
             fruits.append("Apple")
             flag=1
             break
         elif checkvar3.get()==1 and checkvar1.get()==0 and checkvar2.get()==1:
             fruits.append("Banana")
             fruits.append("Pomegranate")
             flag=1
             break
         elif checkvar3.get()==0 and checkvar1.get()==1 and checkvar2.get()==1:
             fruits.append("Apple")
             fruits.append("Pomegranate")
             flag=1
             break
         elif checkvar3.get()==1 and checkvar1.get()==1 and checkvar2.get()==1:
             fruits.append("Banana")
             fruits.append("Apple")
             fruits.append("Pomegranate")
             flag=1
             break
         else :
             fruits.append(" ")

         for fruit in fruits:
             txt += fruit+" "
         l.config(text=txt)
    
   
    
    
    
    
    
checkvar1= tk.IntVar()
checkvar2 = tk.IntVar()
checkvar3 = tk.IntVar()


c1 = tk.Checkbutton(parent, text ="Apple", variable = checkvar1, onvalue=1, offvalue=0,height = 5, width =20, bg="pink", activebackground="yellow", activeforeground="orange", command=print_choice)
c1.pack()
c2 = tk.Checkbutton(parent, text ="Pomegranate", variable = checkvar2, onvalue=1, offvalue=0,height = 5, width =20, bg="pink", command=print_choice)
c2.pack()
c3 = tk.Checkbutton(parent, text ="Banana", variable = checkvar3, onvalue=1, offvalue=0,height = 5, width =20, bg="pink", command=print_choice)
c3.pack()





parent.mainloop()

这是我得到的输出：

每当我尝试选择一个复选框时，Python就会停止响应。有没有可能我在某处遇到了一个无限循环

Answer 1

下面是一个您可能希望如何做到这一点的示例：

from tkinter import Tk, Checkbutton, IntVar


root = Tk()

selected = []


class Choice:
    def __init__(self, text):
        self.text = text
        self.state = IntVar()

        self.checkbutton = Checkbutton(root, text=self.text, command=self.check,
                                       variable=self.state, onvalue=1, offvalue=0)
        self.checkbutton.pack()

    def check(self):
        state = self.state.get()
        if state == 1:
            selected.append(self.text)
        if state == 0:
            selected.remove(self.text)
        print(selected)


c1 = Choice('Apple')
c2 = Choice('Orange')
c3 = Choice('Pear')

root.mainloop()

在这种情况下，您可以根据需要添加任意多的复选框，在硬代码的代码中，您要做的唯一一件事就是启动Choice类，如sovar_name = Choice('checkbutton name')，其中var_name是您想要的任何变量名称，checkbutton name是您想要的任何名称（只是为了澄清）

Answer 2

你不需要很多if-else语句来知道用户喜欢哪种水果

我将向您展示实现同样目标的两种其他方法

第一种方法是创建一个字典，其中水果名作为键，控制变量作为值。 现在遍历这些项，检查控制变量的值是否为1。如果为1，则将其追加到水果列表中

第一种方法（使用字典）：

import tkinter as tk

parent = tk.Tk()
parent.title("My favorite fruits")
l= tk.Label(parent, background="yellow", text="empty", width="30")
l.pack()
w = tk.Label(parent , text ="Select your favorite fruits!", bg="pink", fg = "white")

txt = "you love "
def print_choice():
    global fruit_lst

    for fruit, checked in fruits_dict.items():

        if checked.get() and fruit not in fruit_lst:
            print(fruit)
            fruit_lst.append(fruit)

        if fruit in fruit_lst and not checked.get():
            fruit_lst.remove(fruit)
    
    l.config(text=txt+' ,'.join(fruit_lst))
    

checkvar1= tk.IntVar()
checkvar2 = tk.IntVar()
checkvar3 = tk.IntVar()

fruits_dict = {"Apple": checkvar1, "Pomegranate": checkvar2, "Banana": checkvar3}

fruit_lst = []

c1 = tk.Checkbutton(parent, text ="Apple", variable = checkvar1, onvalue=1, offvalue=0,height = 5, width =20, bg="pink", activebackground="yellow", activeforeground="orange", command=print_choice)
c1.pack()
c2 = tk.Checkbutton(parent, text ="Pomegranate", variable = checkvar2, onvalue=1, offvalue=0,height = 5, width =20, bg="pink", command=print_choice)
c2.pack()
c3 = tk.Checkbutton(parent, text ="Banana", variable = checkvar3, onvalue=1, offvalue=0,height = 5, width =20, bg="pink", command=print_choice)
c3.pack()


parent.mainloop()

您可以使用以下代码避免字典和循环：

import tkinter as tk

parent = tk.Tk()
parent.title("My favorite fruits")
l= tk.Label(parent, background="yellow", text="empty", width="30")
l.pack()
w = tk.Label(parent , text ="Select your favorite fruits!", bg="pink", fg = "white")

txt = "you love "

def current(x, var):
    global fruit_lst

    if var.get():
        fruit_lst.append(x['text'])

    else:
        try:
            fruit_lst.remove(x['text'])
        except ValueError:
            pass
        
    print(fruit_lst)


checkvar1= tk.IntVar()
checkvar2 = tk.IntVar()
checkvar3 = tk.IntVar()


fruit_lst = []

c1 = tk.Checkbutton(parent, text ="Apple", variable = checkvar1, onvalue=1, offvalue=0)
c1.config(command = lambda x=c1, var=checkvar1: current(x, var))
c1.pack()

c2 = tk.Checkbutton(parent, text ="Pomegranate", variable = checkvar2, onvalue=1, offvalue=0)
c2.config(command = lambda x=c2, var=checkvar2: current(x, var))
c2.pack()

c3 = tk.Checkbutton(parent, text ="Banana", variable = checkvar3, onvalue=1, offvalue=0)
c3.config(command = lambda x=c3, var=checkvar3: current(x, var))
c3.pack()

parent.mainloop()