有什么方法可以同步调用QWebEnginePage对象的"toHtml"方法吗? [英] Is there any way to call synchronously the method 'toHtml' which is QWebEnginePage's object?

问题描述

我正在尝试从QWebEnginePage对象获取html代码.根据Qt参考，QWebEnginePage对象的'toHtml'是异步方法，如下所示.

I'm trying to get html code from the QWebEnginePage object. According to Qt reference, QWebEnginePage object's 'toHtml' is asynchronous method as below.

异步方法，以HTML和BODY标记括起来以HTML格式检索页面的内容.成功完成后，将使用页面的内容调用resultCallback.

Asynchronous method to retrieve the page's content as HTML, enclosed in HTML and BODY tags. Upon successful completion, resultCallback is called with the page's content.

所以我试图找出如何同步调用此方法.

so I tried to find out how call this method synchronously.

我想要得到的结果如下.

the result what i want to get is below.

class MainWindow(QWidget):
  html = None
  ...
  ...
  def store_html(self, data):
    self.html = data

  def get_html(self):
    current_page = self.web_view.page()
    current_page.toHtml(self.store_html)
    # I want to wait until the 'store_html' method is finished
    # but the 'toHtml' is called asynchronously, return None when try to return self.html value like below.
    return self.html 
  ...
  ...

感谢您阅读本文.

祝大家有美好的一天.

推荐答案

获得该行为的简单方法是使用 QEventLoop() .此类的对象阻止执行exec_()之后的代码，这并不意味着GUI无法继续工作.

A simple way to get that behavior is to use QEventLoop(). An object of this class prevents the code that is after exec_() from being executed, this does not mean that the GUI does not continue working.

class Widget(QWidget):
    toHtmlFinished = pyqtSignal()

    def __init__(self, *args, **kwargs):
        QWidget.__init__(self, *args, **kwargs)
        self.setLayout(QVBoxLayout())
        self.web_view = QWebEngineView(self)
        self.web_view.load(QUrl("http://doc.qt.io/qt-5/qeventloop.html"))
        btn = QPushButton("Get HTML", self)
        self.layout().addWidget(self.web_view)
        self.layout().addWidget(btn)
        btn.clicked.connect(self.get_html)
        self.html = ""

    def store_html(self, html):
        self.html = html
        self.toHtmlFinished.emit()

    def get_html(self):
        current_page = self.web_view.page()
        current_page.toHtml(self.store_html)
        loop = QEventLoop()
        self.toHtmlFinished.connect(loop.quit)
        loop.exec_()
        print(self.html)


if __name__ == '__main__':
    import sys
    app = QApplication(sys.argv)
    w = Widget()
    w.show()
    sys.exit(app.exec_())

注意:相同的方法适用于PySide2.

Note: The same method works for PySide2.

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