Tkinter 需要一个按钮来在指针打开和指针关闭时更改背景颜色

Question

I have a Python Tkinter Windows program with many buttons. I need a button to change its background color forth and back when the pointer is on it and off it. This issue has been dicussed here before, and I tried to use the code snippets given to solve my problem but did not succeed. The best solution for me would be such that the method would be on such a level that it is needed only once. In my program the user can define the background color for the buttons, however similar to all, and the pointer-on color should be able to be affected by the choice.

Below a minimal code where I have tried to use bind. randint simulates user choice. But, as said, it does not work. What changes do I require? I am new with Python and Tkinter, so please give your answer as clear changes to the code below.

import tkinter as tk
from random import randint

class PointerOnOff:

    def __init__ (self, root):

        root.geometry ("200x140+100+100")
        
        color = randint (0, 2)
        if color == 0:
            off_color = "#aaffaa"
            on_color = "#99ff99"
        elif color == 1:
            off_color = "#ffffaa"
            on_color = "#ffff99"
        else:
            off_color = "#ffaaaa"
            on_color = "#ff9999"
            
        self.OK = tk.Button (root, text = "OK", bg = off_color, command = self.OKPush)
        self.OK.place (x = 50, y = 20, width = 100, height = 30)

        self.Cancel = tk.Button (root, text = "Cancel", bg = off_color, command = self.CancelPush)
        self.Cancel.place (x = 50, y = 60, width = 100, height = 30)

        self.PushedButton = tk.Label (root, text = "")
        self.PushedButton.place (x = 20, y = 100, width = 160, height = 30)
        
    def on_enter (anybutton):
        anybutton.widget.config (bg = on_color)

    def on_leave (anybutton):
        anybutton.widget.config (bg = off_color)
        
        self.OK.bind("<Enter>", on_enter)
        self.OK.bind("<Leave>", on_leave)
        self.Cancel.bind("<Enter>", on_enter)
        self.Cancel.bind("<Leave>", on_leave)
        
    def OKPush (self):
        self.PushedButton.config (text = "You pushed OK button")

    def CancelPush (self):
        self.PushedButton.config (text = "You pushed Cancel button")

root = tk.Tk ()
master = PointerOnOff (root)
root.mainloop ()

Answer 1

I'm python beginner and I'm not sure of my answer but the code for changing the background color is this in my opinion:

from tkinter import *
from random import randint

t = Tk()
t.geometry('200x200')
def change_bg():
    color = ("#" + str(randint(100000, 999999)))
    f = Frame(t, bg=color)
    f.place(x=0, y=0, width=200, height=200)

Answer 2

The issue is due to incorrect indentation of the two functions: on_enter() and on_leave() . They need to be inner functions inside __init__() :

class PointerOnOff:

    def __init__ (self, root):
        ...

        self.PushedButton = tk.Label (root, text = "")
        self.PushedButton.place (x = 20, y = 100, width = 160, height = 30)

        def on_enter (anybutton):
            anybutton.widget.config (bg = on_color)

        def on_leave (anybutton):
            anybutton.widget.config (bg = off_color)

        self.OK.bind("<Enter>", on_enter)
        self.OK.bind("<Leave>", on_leave)
        self.Cancel.bind("<Enter>", on_enter)
        self.Cancel.bind("<Leave>", on_leave)

---

If you don't want to call the two bindings for every button, you better create a custom button class to embed the hover feature:

class HoverButton(tk.Button):
    _colors = [
         # off      # on
        ('#aaffaa', '#99ff99'),
        ('#ffffaa', '#ffff99'),
        ('#ffaaaa', '#ff9999'),
    ]

    def __init__(self, master=None, *args, **kw):
        # if "colors" option not provided, use random choice from internal colors
        self._off_color, self._on_color = kw.pop("colors", self._colors[randint(0, 2)])
        super().__init__(master, *args, **kw)
        self["bg"] = self._off_color
        self.bind("<Enter>", lambda e: self.config(bg=self._on_color))
        self.bind("<Leave>", lambda e: self.config(bg=self._off_color))

Then use this custom button class for those buttons you want to have hover effect:

def class PointOnOff:
    def __init___(self, root):
        ...

        self.OK = HoverButton(root, text="OK", colors=("orange", "gold"), command=self.OKPush)
        self.OK.place(x=50, y=20, width=100, height=30)

        self.Cancel = HoverButton(root, text="Cancel", command=self.CancelPush)
        self.Cancel.place(x=50, y=60, width=100, height=30)

        ...