第一次发射信号后自动断开 [英] Automatically disconnect after first signal emission

问题描述

我正在从文件加载网页，然后替换其中的一些 html:

I am loading a web page from a file, then i replace some of the html in it:

    self.template_web_page = QtWebKit.QWebPage()
    self.template_web_page.mainFrame().load(QtCore.QUrl('template.html'))
    def load(ok):
        main_window.web_view.loadFinished.disconnect(load)
        self.table_element = self.template_web_page.mainFrame().findFirstElement("#table")
        self.table_element.setInnerXml(table_html)
    main_window.web_view.loadFinished.connect(load)

有没有办法只为一次发射就连接到信号?

Is there a way to connect to a signal just for one shot?

推荐答案

如前所述，似乎没有比这更好(更简洁)的方法了.

As already noted, there doesn't appear to be a better (more concise) way than this.

http://comments.gmane.org/gmane.comp.lib.qt.general/6883 表明这样的解决方案很好，尽管我自己也遇到了这样的解决方案的问题.我发现如果我在插槽的开头断开插槽的连接(如问题中的代码中所做的那样)，然后尝试执行一些 GUI 交互(设置状态栏文本是一个问题，但没有在列表视图中突出显示一行)，由于 NULL 指针取消引用，我得到了一个异常.这是针对 Windows 的 Python 2.6 的 PyQt 4.6.2.当我将 disconnect() 调用移到插槽的末尾时，问题就消失了.

http://comments.gmane.org/gmane.comp.lib.qt.general/6883 suggests that such a solution is fine, although I have had issues with such a solution myself. I found that if I disconnected the slot at the start of the slot (as is done in the code in the question) and then tried to perform some GUI interactions (setting statusbar text was a problem, but not highlighting a row in a list view), I got an exception due to a NULL pointer dereference. This was with PyQt 4.6.2 for Python 2.6 for Windows. When I moved the disconnect() call to the end of the slot, the problem went away.

如果这不相关，请提前道歉，这只是我犯的一个愚蠢的错误.

Apologies in advance if this is not relevant and it's just a stupid mistake I've made.

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