为什么我的 Tk 按钮会被自动按下? [英] Why is my Tk button being pressed automatically?

问题描述

在下面的代码中，单击按钮应该将黑色文本从 Hello 更改为 Goodbye.但是当我运行程序时，它立即说再见.

In the code below, clicking the button should change the black text from Hello to Goodbye. But when I run the program, it immediately says Goodbye.

from Tkinter import *
from tkMessageBox import *
print "this is a test"


class Demo(Frame):
    def __init__(self):
        self.createGUI()
        print "init"
        #self.__mainWindow = Tk()
    def destroy(self):
        print "destroy"
    def createGUI(self):
        Frame.__init__(self)
        self.pack(expand = YES, fill = BOTH)
        self.master.title("Demo")
        self.trackLabel = StringVar()
        self.trackLabel.set("Hello")
        self.trackDisplay = Label(self, font = "Courier 14", textvariable = self.trackLabel, bg = "black", fg = "green")
        self.trackDisplay.grid(sticky = W+E+N+S)
        self.button1 = Button(self, text = "Click Me", width = 10, command = self.bpress())
        self.button1.grid(row = 2, column = 0, sticky = W+E+N+S)

    def bpress(self):
        self.trackLabel.set("Goodbye")
# run the program
def main():
    tts = Demo()
    tts.mainloop()

if __name__ == "__main__":
    main()

推荐答案

因为您在创建 self.button1 按钮时正在调用 self.bpress:

Because you are calling self.bpress when you create the self.button1 button:

self.button1 = Button(self, text = "Click Me", width = 10, command = self.bpress())
#                                                                               ^^

只需删除括号并将command分配给self.bpress函数对象本身:

Simply remove the parenthesis and assign command to the self.bpress function object itself:

self.button1 = Button(self, text = "Click Me", width = 10, command = self.bpress)

这篇关于为什么我的 Tk 按钮会被自动按下?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！