如何检查 tkinter 。 文本解析堆栈?
原标题：How to examine tkinter.Text undo stack?
Tk 文档谈到撤消堆栈, 但没有提到直接检查它的可能性 。 我希望在撤消堆栈用完后显示 Undo 命令为不活动 。 跟踪撤消和重做是我唯一的机会, 还是有办法询问堆栈是否是空的?
最佳回答
There is no way to explicitly examine the undo stack. However, you might be able to use the modified flag to serve a similar purpose.
From the official tk documentation:
The undo mechanism is also linked to the modified flag. This means that undoing or redoing changes can take a modified text widget back to the unmodified state or vice versa. The modified flag will be set automatically to the appropriate state. This automatic coupling does not work when the modified flag has been set by the user, until the flag has been reset again.
问题回答
To check whether or not you can undo/redo, you can use text.edit("canundo") and text.edit("canredo")
This is from the tcl/tk documentation (since version 8.6):
pathName edit canredo
Returns a boolean true if redo is possible, i.e. when the redo stack is not empty. Otherwise returns false.
pathName edit canundo
Returns a boolean true if undo is possible, i.e. when the undo stack is not empty. Otherwise returns false.
It s not built into tkinter as a function yet so we have to use an internal method:
def edit(self, *args):
"""Internal method
This method controls the undo mechanism and
the modified flag. The exact behavior of the
command depends on the option argument that
follows the edit argument. The following forms
of the command are currently supported:
edit_modified, edit_redo, edit_reset, edit_separator
and edit_undo
"""
return self.tk.call(self._w, edit , *args)
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