python之tkinter 单选按钮不更新变量

--更新: 我变了

variable=self.optionVal.get() 

到

variable=self.optionVal 

但是什么都没有改变。另外我想知道为什么它在编译时自动调用self.selected？

----原文:

我正在尝试熟悉单选按钮，但我认为我不了解单选按钮的工作原理。下面是一个简短的演示代码:

     self.optionVal = StringVar() 
     for text, val in OPTIONS: 
         print(text,val) 
         radioButton = Radiobutton(self, 
                                   text=text, 
                                   value=val, 
                                   variable=self.optionVal.get(), 
                                   command = self.selected()) 
        radioButton.pack(anchor=W)  
 
     def selected(self): 
        print("this option is :"+self.optionVal.get()) 
 
In my opinion this should work like once I choose certain button, and it prints out "this option is *the value*", however now what it does is once compiled, it prints out everything, and the self.optionVal.get() is blankspace, as if value wasn't set to that variable. 
 
I wonder what happens to my code, 
Many thanks in advance.  

请您参考如下方法:

啊哈!我相信我已经想通了。我有完全相同的问题。确保你正在为 IntVar 分配一个 master，比如 self.rbv=tk.IntVar(master) #or 'root' 或者你正在使用的任何东西):

import Tkinter as tk 
import ttk 
 
class My_GUI: 
 
    def __init__(self,master): 
        self.master=master 
        master.title("TestRadio") 
 
        self.rbv=tk.IntVar(master)#<--- HERE! notice I specify 'master' 
        self.rb1=tk.Radiobutton(master,text="Radio1",variable=self.rbv,value=0,indicatoron=False,command=self.onRadioChange) 
        self.rb1.pack(side='left') 
        self.rb2=tk.Radiobutton(master,text="Radio2",variable=self.rbv,value=1,indicatoron=False,command=self.onRadioChange) 
        self.rb2.pack(side='left') 
        self.rb3=tk.Radiobutton(master,text="Radio3",variable=self.rbv,value=2,indicatoron=False,command=self.onRadioChange) 
        self.rb3.pack(side='left') 
 
    def onRadioChange(self,event=None): 
        print self.rbv.get() 
 
root=tk.Tk() 
gui=My_GUI(root) 
root.mainloop() 

尝试运行它，单击不同的按钮(它们是单选按钮，但 indicatoron=False)，您将看到它打印正确更改的值!