Python 获取焦点条目名称

Question

我试图在按下向上或向下箭头键时增加或减少输入值。为此，我需要首先找到焦点所在的条目，我正在尝试执行“.focus_get()”。问题是我无法弄清楚它是如何工作的或者它返回了什么。它为每个条目返回 1 个唯一编号，例如:“.45191744”，但每次运行程序时此编号都会更改。以下数字是运行代码时的最后 5 次尝试。“.50518728”“.53009096”“.55889592”“.51891896”

如何获取焦点条目的变量名？

这是我的代码:

def get_focus1(event):
    print("return: event.widget is", event.widget)
    print("focus is:", window2.focus_get())
    print(window2.focus_get())
    print(help(window2.Entry))

window2 = Tk()

eyear1 = Entry(window2, width=4, font=("Helvetica", 16)) #  Entry for year
eyear1.insert(10, defaultYear)
eyear1.grid(row=1, column=1)

emonth1 = Entry(window2, width=4, font=("Helvetica", 16)) #  Entry for Month
emonth1.insert(10, defaultMonth)
emonth1.grid(row=1, column=2)

eday1 = Entry(window2, width=4, font=("Helvetica", 16)) #  Entry for day
eday1.insert(10, defaultDay)
eday1.grid(row=1, column=3)

window2.bind('<Left>', get_focus1)

mainloop()

Answer 1

focus_get 返回实际对象。 假设您有充分的理由不使用 textvariable (请参阅 Bryan 的评论)，您想做的是清除文本并重新写入新值(做一些验证显然)。你最终得到的是这样的:

from tkinter import *

def up(event):
    # warning, exceptions can happen
    old = int(event.widget.get()) # this gives back the actual object!
    event.widget.delete(0, END) # delete existing text
    event.widget.insert(10, old + 1) # put new text in

def down(event):
    # warning, exceptions can happen
    old = int(event.widget.get()) # this gives back the actual object!
    event.widget.delete(0, END) # delete existing text
    event.widget.insert(10, old - 1) # put new text in

window2 = Tk()

eyear1 = Entry(window2, width=4, font=("Helvetica", 16)) #  Entry for year
eyear1.insert(10, 2015)
eyear1.grid(row=1, column=1)

emonth1 = Entry(window2, width=4, font=("Helvetica", 16)) #  Entry for Month
emonth1.insert(10, 1)
emonth1.grid(row=1, column=2)

eday1 = Entry(window2, width=4, font=("Helvetica", 16)) #  Entry for day
eday1.insert(10, 10)
eday1.grid(row=1, column=3)

# bind both keys to corresponding event handlers
window2.bind('<Up>', up)
window2.bind('<Down>', down)
mainloop()