tkinter GUI（灯光未显示在我的窗口中）

Question

三个灯通过单选按钮操作谁能帮我找出原因吗？下面的代码没有给出错误，但没有输出:( 在我的根目录上出现其他图标（此处不包括），但下面的代码部分不起作用？from tkinter import *root = Tk()frame = Frame(root)frame.pack()color = StringVar() radio_red = Radiobutton(frame, text="Red", bg="red", variable= color, value="R", command= on_RadioChange) radio_red.grid(row=10, column=1) radio_yellow = Radiobutton(frame, text="Yellow", bg="yellow", variable= color, value="Y", command= on_RadioChange)                radio_yellow.grid(row = 10, column = 2) radio_green = Radiobutton(frame, text="Green", bg="green", variable= color, value="G", command= on_RadioChange) radio_green.grid(row = 10, column = 3) canvas = Canvas(root, width=450, height=300, bg="white") canvas.pack() oval_red = canvas.create_oval(10, 10, 110, 110, fill="white") oval_yellow = canvas.create_oval(120, 10, 220, 110, fill="white") oval_green = canvas.create_oval(230, 10, 330, 110, fill="white")  color.set('R')  canvas.itemconfig(oval_red, fill="red")          root.mainloop()       def on_RadioChange():        color = color.get()        if color == 'R':            canvas.itemconfig(oval_red, fill="red")            canvas.itemconfig(oval_yellow, fill="white")            canvas.itemconfig(oval_green, fill="white")        elif color == 'Y':            canvas.itemconfig(oval_red, fill="white")            canvas.itemconfig(oval_yellow, fill="yellow")            canvas.itemconfig(oval_green, fill="white")        elif color == 'G':            canvas.itemconfig(oval_red, fill="white")            canvas.itemconfig(oval_yellow, fill="white")            canvas.itemconfig(oval_green, fill="green")

Answer 1

您可能应该了解如何使用类，但这里有一个有关如何在给定代码中使用类的示例。

from tkinter import *

class TrafficLights:

    def value(self):

        root = Tk()

        frame = Frame(root)

        frame.pack()

        self.color = StringVar()

        radio_red = Radiobutton(frame, text="Red", bg="red", variable= self.color, value="R", command= self.on_RadioChange)

        radio_red.grid(row=10, column=1)

        radio_yellow = Radiobutton(frame, text="Yellow", bg="yellow", variable= self.color, value="Y", command= self.on_RadioChange)               

        radio_yellow.grid(row = 10, column = 2)

        radio_green = Radiobutton(frame, text="Green", bg="green", variable= self.color, value="G", command= self.on_RadioChange)

        radio_green.grid(row = 10, column = 3)

        self.canvas = Canvas(root, width=450, height=300, bg="white")

        self.canvas.pack()

        self.oval_red = self.canvas.create_oval(10, 10, 110, 110, fill="white")

        self.oval_yellow = self.canvas.create_oval(120, 10, 220, 110, fill="white")

        self.oval_green = self.canvas.create_oval(230, 10, 330, 110, fill="white")

        self.color.set('R')

        self.canvas.itemconfig(self.oval_red, fill="red")

        

        root.mainloop()

    def on_RadioChange(self):

        color = self.color.get()

        if color == 'R':

            self.canvas.itemconfig(self.oval_red, fill="red")

            self.canvas.itemconfig(self.oval_yellow, fill="white")

            self.canvas.itemconfig(self.oval_green, fill="white")

        elif color == 'Y':

            self.canvas.itemconfig(self.oval_red, fill="white")

            self.canvas.itemconfig(self.oval_yellow, fill="yellow")

            self.canvas.itemconfig(self.oval_green, fill="white")

        elif color == 'G':

            self.canvas.itemconfig(self.oval_red, fill="white")

            self.canvas.itemconfig(self.oval_yellow, fill="white")

            self.canvas.itemconfig(self.oval_green, fill="green")

a = TrafficLights()

a.value()

主要错误是您没有使用self也没有调用该方法value()。所以我修复了所有这些。因此，如果您不想调用value()，那么您可以将 Changedef value(self)与 def 一起使用__init__(self):，这样您现在就不必调用了a.value()。我建议您在继续学习 python 和 tkinter 课程之前先学习更多有关 OOP 的知识。

更新：

没有什么太大的问题，只是重新排列代码并将color内部函数更改为colors其他内容，完成的代码将是：

from tkinter import *

root = Tk()

def on_RadioChange():

        colors = color.get()

        if colors == 'R':

            canvas.itemconfig('oval_red', fill="red")

            canvas.itemconfig('oval_yellow', fill="white")

            canvas.itemconfig('oval_green', fill="white")

        elif colors == 'Y':

            canvas.itemconfig('oval_red', fill="white")

            canvas.itemconfig('oval_yellow', fill="yellow")

            canvas.itemconfig('oval_green', fill="white")

        elif colors == 'G':

            canvas.itemconfig('oval_red', fill="white")

            canvas.itemconfig('oval_yellow', fill="white")

            canvas.itemconfig('oval_green', fill="green")

frame = Frame(root)

frame.pack()

color = StringVar()

radio_red = Radiobutton(frame, text="Red", bg="red", variable=color, value="R", command=on_RadioChange)

radio_red.grid(row=10, column=1)

radio_yellow = Radiobutton(frame, text="Yellow", bg="yellow", variable=color, value="Y", command=on_RadioChange)               

radio_yellow.grid(row = 10, column = 2)

radio_green = Radiobutton(frame, text="Green", bg="green", variable=color, value="G", command=on_RadioChange)

radio_green.grid(row = 10, column = 3)

canvas = Canvas(root, width=450, height=300, bg="white")

canvas.pack()

canvas.create_oval(10, 10, 110, 110, fill="white",tag='oval_red')

canvas.create_oval(120, 10, 220, 110, fill="white",tag='oval_yellow')

canvas.create_oval(230, 10, 330, 110, fill="white",tag='oval_green')

color.set('R')

canvas.itemconfig('oval_red', fill="red")

    

root.mainloop()

为什么color要改为colors？当您使用color实际引用colorwith时color，这会引发一个UnboundLocalError: local variable 'color' referenced before assignment（因为它在函数内部？），因此要摆脱它，只需重命名（仅在这种情况下）。这是最好的方法吗？我不这么认为，您可以在这里删除一些无用的变量。