为什么文本光标坐标没有正确更新? [英] Why Text cursor coordinates are not updated correctly?
问题描述
为了为我的文本编辑器创建一个简单的行列计数器，我决定简单地使用 tkinter.Text 小部件的 index 函数.实际上，index 函数返回一个字符串，表示作为参数传递给它的坐标的行和列.
To create a simple line-column counter for my text editor, I decided to simply use the index function of the tkinter.Text widget. In fact, the index function returns a string representing the line and column of the coordinates passed as argument to it.
具体来说，我使用 cursor_pos = text.index(tkinter.INSERT) 来获取光标的索引，因为，从 effbot 网站:
Specifically, I am using cursor_pos = text.index(tkinter.INSERT) to get the index of the cursor, since, from the effbot website on tkinter.INSERT:
tkinter.INSERT 对应插入光标.
tkinter.INSERT corresponds to the insertion cursor.
问题是 tkinter.INSERT 似乎给了我最后一个光标位置，直到我用箭头移动光标(例如).
The problem is that tkinter.INSERT seems to give me the last cursor position until I move the cursor with the arrows (for example).
这是处理行数和列数的函数:
This is the function that handles the count of the lines and columns:
def on_key_pressed(self, event=None):
"""Docs """
if self.tpane is not None:
print(self.lines, self.columns)
self.tpane.update()
cursor_pos = self.tpane._tabs[self.tpane.selected()].text.index(tkinter.INSERT)
self.lines = int(cursor_pos.split('.')[0])
self.columns = int(cursor_pos.split('.')[1])
print(self.lines, self.columns)
self.line_c.config(text='Lines: ' + str(self.lines))
self.col_c.config(text='Columns: ' + str(self.columns))
self.update()
我不知道你能不能理解这种情况...当我第一次在编辑器上输入一个字母时，self.columns 变量不会更新为 1(保持为 0)，直到我写第二个字母，它更新为 1，依此类推.但是有一个技巧可以让它在不写新信的情况下更新.写完第一个字母后，如果我用箭头移动光标，它会将 self.columns 更新为实际 1.
I don't know if you can understand the situation... When I first type a letter on the editor, the self.columns variable does not update to 1 (remains 0) until I write the second letter, where it updates to 1, and so on. But there's a trick to make it update without writing a new letter. Once written the first letter, if I move the cursor with the arrows, it updates the self.columns to actually 1.
另一个问题是当我尝试删除一个存在的字符时.例如，如果我有 3 个字符(假设我有 self.columns 到 3)，然后按 delete，self.columns 更新莫名其妙地变成4，如果我尝试删除另一个字符，此时它会更新为3.
Another problem is when I try to delete a existent character. For example, if I have 3 characters (and suppose I have self.columns to 3), and I press delete, self.columns update inexplicably to 4, and if I try to remove another character, at this point, it updates to 3.
on_key_pressed 事件处理程序中的 self.lines 也存在此问题.我不确定这是否应该发生，如果是，那么我错过了什么......
This problems exists also for the self.lines in the on_key_pressed event handler. I am not sure if this is supposed to happen, and if yes, then I am missing something...
推荐答案
发生这种情况是因为您的自定义绑定在内置绑定之前触发，而实际上是内置绑定修改了小部件并更改了光标位置.
This happens because your custom binding fire before the built-in bindings, and it is the built-in bindings that actually modify the widget and change the cursor position.
您可以利用绑定标签更改顺序.有关更多信息，请参阅此问题:关于 tkinter 中的绑定标签的基本查询
You can change the order by leveraging bindtags. For more information see this question: Basic query regarding bindtags in tkinter
有关如何更改绑定标签的示例，请参阅此答案:https://stackoverflow.com/a/3513906/7432
For an example of how to change the bindtags, see this answer: https://stackoverflow.com/a/3513906/7432
如果不想处理绑定标签，可以绑定到
If you don't want to deal with bindtags, you can bind to <KeyRelease>. Built-in bindings happen on a key press, so the release binding will always fire after the widget has been updated.
这篇关于为什么文本光标坐标没有正确更新?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
