在 Tkinter 文本小部件中更改退格效果

Question

我正在寻找一种方法来更改 Tkinter 文本小部件中的退格键效果。我正在从 Tkinter 监视文本窗口中的关键事件，我需要找到一种方法：

• 禁用 Backspace 键的效果，但仍然可以知道它是输入的

• 删除用户打算删除的字符

我不知道从哪里开始。我可以挑出 Backspace 事件，但不知道如何防止它删除字符。我也不知道如何实时影响输入（在用户书写时对字符应用删除线“样式”）

这是我现在所拥有的，但这并不多：

from Tkinter import *
import tkFileDialog
root=Tk()
root.title("TextnonEdit")
text=Text(root)
text.grid()

def keepit(key):
    print key.keysym
    if key.keysym == "BackSpace":
        print "do not delete, strikethrough"

# Bind entry to keypress
text.bind("<Key>", keepit)

def saveas():
    global text
    t = text.get("1.0", "end-1c")
    savelocation=tkFileDialog.asksaveasfilename()
    file1=open(savelocation, "w+")
    file1.write(t)
    file1.close()

button=Button(root, text="Save", command=saveas)
button.grid()
root.mainloop()

提前感谢您的任何回答！

Answer 1

问题可以通过以下方式解决：

1. 在文本小部件上创建一个标签，并将 overstrike 属性设置为 true
2. 在退格字符上创建绑定以应用标记
3. 让绑定函数返回"break" 以防止默认行为

示例：

import Tkinter as tk

class Example(tk.Frame):
    def __init__(self, parent):
        tk.Frame.__init__(self, parent)

        self.text = tk.Text(self)
        self.text.pack(fill="both", expand=True)

        # add a tag that lets us apply the overstrike attribute
        self.text.tag_configure("overstrike", overstrike=True)

        # add a binding on the backspace key
        self.text.bind("<BackSpace>", self.handleBackspace)

    def handleBackspace(self, event):
        # add the overstrike to the character before the
        # insertion cursor
        self.text.tag_add("overstrike", "insert-1c", "insert")

        # move the cursor to the previous position
        self.text.mark_set("insert", "insert-1c")

        # prevent the default behaviour
        return "break"

if __name__ == "__main__":
    root = tk.Tk()
    Example(root).pack(fill="both", expand=True)
    root.mainloop()

Answer 2

谢谢布赖恩！这是我经过一些调整后得到的结果，以使其能够连续使用多个退格键并删除选择：

import Tkinter as tk

x = 0

class Example(tk.Frame):
    def __init__(self, parent):
        tk.Frame.__init__(self, parent)
        self.text = tk.Text(self)
        self.text.pack(fill="both", expand=True)
        # add a tag that lets us apply the overstrike attribute
        self.text.tag_configure("overstrike", overstrike=True)


        self.text.bind("<Key>", self.eyeout)

        # add a binding on the backspace key
        self.text.bind("<BackSpace>", self.handleBackspace)

    def eyeout(self, key):
        global x
        print key.keysym
        # move the cursor to the previous position
        self.text.mark_set("insert", "insert+" + str(x) + "c")

        print "insert+" + str(x) + "c"

        #reset consecutive backspace count to zero

        x = 0

    def handleBackspace(self, event):

        if self.text.tag_ranges(tk.SEL):
            print ('Selected text !')
            #if text is selected, overstrike all the selection
            self.text.tag_add("overstrike", "sel.first", "sel.last")
            # move cursor to end of selection
            self.text.mark_set("insert", "sel.last")
            # deselect to avoid overwrite
            self.text.tag_remove(tk.SEL, "sel.first", "sel.last")
            # counting doesn't apply to selection, reset backspace count
            global x
            x = 0
        else:
            print('NO Selected Text')
            # add the overstrike to the character before the
            # insertion cursor
            self.text.tag_add("overstrike", "insert-1c", "insert")
            # counting system to know how many backspaces in a row were entered
            print "Backspace!"
            print x
            global x
            x = x+1
            print x
            print "Backspace increase"
            self.text.mark_set("insert", "insert-1c")

        # prevent the default behaviour
        return "break"


if __name__ == "__main__":
    root = tk.Tk()
    Example(root).pack(fill="both", expand=True)
    root.mainloop()