python - TKinter:捕获按键时无响应

对于捕获按键的工作方式，我可能会有根本的误解。我已经设置了基本的按键和效果，但是当我尝试在较大的脚本中执行相同的操作时，它没有效果。例如，第一个程序运行正常。我按空格键，窗口关闭。

import Tkinter as tk
class ExampleApp(tk.Tk):
    def __init__(self):
        def pressSpace(event):
            self.destroy()

        tk.Tk.__init__(self)
        w, h = self.winfo_screenwidth(), self.winfo_screenheight()
        self.geometry("%dx%d+0+0" % (w, h))
        self.bind("<space>", pressSpace)
if __name__ == "__main__":
    app = ExampleApp()
    app.mainloop()

但是，第二个按钮似乎在按下空格时没有任何作用。

#Program has been greatly simplified without affecting the outcome
import Tkinter as tk
class ExampleApp(tk.Tk):
    def __init__(self):
        tk.Tk.__init__(self)

        # make program fullscreen
        w, h = self.winfo_screenwidth(), self.winfo_screenheight()
        self.geometry("%dx%d+0+0" % (w, h))

        self.label = tk.Label(self)
        self.label.pack()
        self.remaining = 0
        self.countdown(15)

    def countdown(self, remaining = None):
        paused = 0
        def pressSpace(event):
            if(paused == 0):
                paused = 1
            else:
                paused = 0

        #bind spacebar to pause the timer
        self.bind(self, "<space>", pressSpace)

        if remaining is not None:
            self.remaining = remaining

        if self.remaining <= 0:
            #Time has expired. Players lose
            self.label.configure(text="TIME!", fg='black', bg='brown')
        else:
            #There is still time on the clock. This cuts the time into readable chunks
            self.label.configure(text= str(self.remaining) + ' - Paused = ' + str(paused))
            if(paused == 0):
                #Check if the timer is toggled to pause
                self.remaining = self.remaining - 1
                self.after(1000, self.countdown)
if __name__ == "__main__":
    app = ExampleApp()
    app.mainloop()

我不明白该程序在功能上似乎相似，并且所有内容都包含在同一功能中，但是变量“ paused”似乎根本没有变化，并且计时器也不会停止。

我很害怕。我偏离了路径吗？

最佳答案

您的代码中有很多问题-


您的绑定似乎是错误的-

self.bind(self, "<space>", pressSpace)

不知道为什么再次发送self。你应该做的-

self.bind("<space>", pressSpace)

在您的函数-pressSpace()中-由于您正在设置paused=0或paused=1，因此暂停的内容将被视为该函数的局部变量，因此会出现错误-UnboundLocalError: local variable 'paused' referenced before assignment。相反，我会让您将paused设置为self上的实例变量并使用它。
其次，即使绑定正确，在每次对countdown的调用中，您都将paused改回0。为此，您应该将绑定和暂停设置为0的逻辑移到__init__()。然后在取消暂停应用程序时，您需要重新开始倒计时。


有效的代码-

import Tkinter as tk
class ExampleApp(tk.Tk):
    def __init__(self):
        tk.Tk.__init__(self)

        # make program fullscreen
        w, h = self.winfo_screenwidth(), self.winfo_screenheight()
        self.geometry("%dx%d+0+0" % (w, h))

        self.label = tk.Label(self)
        self.label.pack()
        self.remaining = 0
        self.paused = 0
        def pressSpace(event):
            if(self.paused == 0):
                self.paused = 1
            else:
                self.paused = 0
                self.countdown()

        #bind spacebar to pause the timer
        self.bind("<space>", pressSpace)
        self.countdown(15)

    def countdown(self, remaining = None):
        if remaining is not None:
            self.remaining = remaining

        if self.remaining <= 0:
            #Time has expired. Players lose
            self.label.configure(text="TIME!", fg='black', bg='brown')
        else:
            #There is still time on the clock. This cuts the time into readable chunks
            self.label.configure(text= str(self.remaining) + ' - Paused = ' + str(self.paused))
            if(self.paused == 0):
                #Check if the timer is toggled to pause
                self.remaining = self.remaining - 1
                self.after(1000, self.countdown)
if __name__ == "__main__":
    app = ExampleApp()
    app.mainloop()

关于python - TKinter:捕获按键时无响应，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/32546386/