Question

三个灯通过单选按钮操作

有人可以帮助我找出原因吗？下面的代码没有错误，但是没有输出：（在我的根目录下，出现了其他图标（此处未包括），但是下面的代码不起作用？

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，但这是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并且没有调用方法value()。因此，我修复了所有这些问题。因此，如果您不想调用value()，则可以将def def value(self)与更改__init__(self):一起使用，这样现在就不必调用a.value()。我建议您在继续使用python和tkinter进行学习之前，先学习有关OOP的更多信息。

更新：

没什么大不了的，只是重新排列代码并将color内部函数更改为colors或其他内容，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()

为什么将color更改为colors？当您使用color实际使用color来引用color时，这将引发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，这里有一些无用的变量可以消除。

tkinter GUI（灯不显示在我的窗口中）

1 个答案: