PySide, QtWebKit - loadFinished signal is never emitted

Question

import sys
from PySide import QtGui, QtWebKit, QtCore

class WebPageProcessor(object):

    def __init__(self, browser):
        self.browser = browser
        self.browser.loadFinished.connect(self.test)
        self.browser.load('http://google.com')

    def test(self, ok):
        print(ok)


class Browser(QtGui.QWidget):

    def __init__(self):
        super().__init__()
        self.init_ui()
        bot = WebPageProcessor(self.browser)

    def init_ui(self):
        self.browser = QtWebKit.QWebView()

        grid = QtGui.QGridLayout()
        grid.setContentsMargins(0, 0, 0, 0)
        grid.addWidget(self.browser, 0, 0)
        self.setLayout(grid)


if __name__ == '__main__':
    app = QtGui.QApplication(sys.argv)
    browser = Browser()
    browser.show()
    app.exec_()

'Browser' class is the UI browser and 'WebPageProcessor' is the class which controls it.

I have binded 'loadFinished' signal to the browser but it's never called.

If I resign from 'WebPageProcessor' class and put all it's code into 'init_ui' method, then the signal is emitted correctly.

What's the reason and how to fix it?

Answer 1

The loadFinished certainly is emitted. But the test slot will never be called, because it gets deleted immediately after it is connected. This is because you're allowing the instance of WebPageProcessor to be garbage-collected once __init__ has returned.

Try this instead:

    self.bot = WebPageProcessor(self.browser)