python - gtk 文本 itters 的问题

Question

我有一个使用 gtk 用 python 编写的应用程序，我希望它自动关闭括号并将光标放在它们之间问题是我随机收到以下错误并使程序崩溃:

    ./mbc.py:266: GtkWarning: Invalid text buffer iterator: either the iterator is 
uninitialized, or the characters/pixbufs/widgets in the buffer have been modified since
 the iterator was created.
    You must use marks, character numbers, or line numbers to preserve a position across
 buffer modifications.
    You can apply tags and insert marks without invalidating your iterators,
    but any mutation that affects 'indexable' buffer contents (contents that can be 
referred to by character offset)
    will invalidate all outstanding iterators
      buff.place_cursor(buff.get_iter_at_line_offset(itter.get_line(),Iter.get_offset()-1))
    ./mbc.py:266: GtkWarning: gtktextbtree.c:4094: char offset off the end of the line
      buff.place_cursor(buff.get_iter_at_line_offset(itter.get_line(),Iter.get_offset()-1))

    Gtk-ERROR **: Char offset 568 is off the end of the line
    aborting...
    Aborted

该区域的代码是这样的:

def insert_text(self, buff, itter, text, length):
    if text == '(':
        buff.insert_at_cursor('()') 
        mark = buff.get_mark('insert')
        Iter = buff.get_iter_at_mark(mark)
        buff.place_cursor(buff.get_iter_at_line_offset(itter.get_line(),Iter.get_offset()-1))

谁能告诉我如何修复这个错误？我找不到任何其他方法将光标放置在括号之间的特定位置

Answer 1

insert_at_cursor 调用会使传入函数的迭代器无效。当您返回最后一行的迭代器时，GTK+ 会显示警告。 GTK+ Text Widget Overview 中解释了此行为.

解决这个问题是不重复使用迭代器，例如:

buff.insert_at_cursor(')')  # This invalidates existing iterators.
mark = buff.get_mark('insert')
iter = buff.get_iter_at_mark(mark)  # New iterator
iter.backward_cursor_positions(1)
buff.place_cursor(iter)

(免责声明:我已经很长一段时间没有使用 GTK+ 文本小部件了。可能有一种更简单/更优雅的方法来完成同样的事情，但这个可以完成这项工作。)