Python GUI - 如何通过按下键盘输入来更改按钮的颜色？答案

【问题标题】：Python GUI - How to change a button's colour by pressing a keyboard input?Python GUI - 如何通过按下键盘输入来更改按钮的颜色？
【发布时间】：2021-04-14 08:55:27
【问题描述】：

我用 Python 编写了一个程序，其中有一个 GUI，它显示 4 个按钮（左上右下），当我从键盘按下它们时，它们会返回一条消息。我想要的是，当我按下按钮时，我希望框字段以红色或其他颜色+显示按下哪个按钮的消息。

from tkinter import *


window = Tk()
window.title("Arrow Keys")
window.geometry('820x640')
width = 820
height = 640


myButton1 = Button(window, text="    UP   ", activebackground='red')
myButton1.place(x= 387, y=10)
myButton2 = Button(window, text="DOWN", activebackground='red')
myButton2.place(x= 399, y= 60)
myButton2.pack(pady=60)
myButton3 = Button(window, text=" LEFT ", activebackground='red')
myButton3.place(x= 345, y=35)
myButton4 = Button(window, text="RIGHT", activebackground='red')
myButton4.place(x= 435, y= 35)

def up(event):
    myLabel = Label(window, text="Press UP")
    myLabel.pack()

def down(event):
    myLabel = Label(window, text="Press DOWN")
    myLabel.pack()

def left(event):
    myLabel = Label(window, text="Press LEFT")
    myLabel.pack()

def right(event):
    myLabel = Label(window, text="Press RIGHT")
    myLabel.pack()

window.bind("<Up>", up)
window.bind("<Down>", down)
window.bind("<Left>", left)
window.bind("<Right>", right)

window.mainloop()

【问题讨论】：

myButton1.configure(bg='yellow') in up 是否满足您的需求？参看。 stackoverflow.com/questions/36093839/…
谢谢！但是我想当我按下“键盘上的向上箭头”时，GUI 上的 UP 按钮应该亮起一种颜色，给我一个视觉信号，我按下它，当我释放向上箭头时，GUI 上的按钮应该变成灰色再次（禁用）

标签： python tkinter

【解决方案1】：

您还需要绑定相应的KeyRelease-* 事件。例如，添加到您的代码中：

def up(event):
   ...
   myButton1.configure(bg='yellow')

def up_release(event):
   myButton1.configure(bg='grey')

...
window.bind("<KeyRelease-Up>", up_release)

参见例如TkInter keypress, keyrelease events 了解更多详情，How to reset background color of a python tkinter button? 恢复以前的颜色（而不是灰色）。

【讨论】：

【解决方案2】：

在回调函数外定义状态标签myLabel
定义一个字典来链接键名和对应的按钮
将<KeyPress>和<KeyRelease>绑定到对应的回调中，并在回调中更新对应按钮的背景颜色和myLabel的文字

from tkinter import *

window = Tk()
window.title("Arrow Keys")
window.geometry('820x640')
width = 820
height = 640

myButton1 = Button(window, text="    UP   ", activebackground='red')
myButton1.place(x= 387, y=10)
myButton2 = Button(window, text="DOWN", activebackground='red')
myButton2.place(x= 399, y= 60)
#myButton2.pack(pady=60) ### don't call pack() after using place()
myButton3 = Button(window, text=" LEFT ", activebackground='red')
myButton3.place(x= 345, y=35)
myButton4 = Button(window, text="RIGHT", activebackground='red')
myButton4.place(x= 435, y= 35)

# save the background color or button
btn_bg = myButton1.cget("bg")

myLabel = Label(window)
myLabel.place(x=50, y=50)

keys = {"Up": myButton1, "Down": myButton2, "Left": myButton3, "Right": myButton4}

def on_key_press(event):
    if event.keysym in keys:
        keys[event.keysym].config(bg="red")
        myLabel.config(text=event.keysym)

def on_key_release(event):
    if event.keysym in keys:
        keys[event.keysym].config(bg=btn_bg)
        myLabel.config(text="")

window.bind("<KeyPress>", on_key_press)
window.bind("<KeyRelease>", on_key_release)

window.mainloop()

【讨论】：