Question

我有一个PyQt4类，它显示一个html表单并获取输入，这要归功于之前的questions here（older one is here}。

现在我想退出主循环，执行其他操作并稍后使用不同的html表单重新启动主循环。问题是，我的事件句柄在主循环的第二次执行中不起作用。我做错了什么？

问题似乎是，当第二次调用MyWebPage时，类app.exec_()无法正常工作，因为表单未提交。

这是我运行的代码，但不提交第二种形式：

import sys
from urllib import unquote_plus

from PyQt4 import QtCore, QtGui, QtWebKit

class MyWebPage(QtWebKit.QWebPage):
    formSubmitted = QtCore.pyqtSignal(QtCore.QUrl)

    def acceptNavigationRequest(self, frame, req, nav_type):
        if nav_type == QtWebKit.QWebPage.NavigationTypeFormSubmitted:
            self.formSubmitted.emit(req.url())
        return super(MyWebPage, self).acceptNavigationRequest(frame, req, nav_type)



class PsyTML(QtGui.QWidget):
    def __init__(self):
        super(PsyTML, self).__init__()
        self.elements = {}
        self.view = QtWebKit.QWebView(self)
        layout = QtGui.QVBoxLayout(self)
        layout.addWidget(self.view)
        layout.setContentsMargins(0, 0, 0, 0)
        self.view.setPage(MyWebPage())
        self.view.page().formSubmitted.connect(self.handleFormSubmitted)

    def viewPsyTML(self, html):
        self.view.setHtml(html)
        self.show()

    def handleFormSubmitted(self, url):
        elements = self.elements
        self.close()
        for key, value in url.encodedQueryItems():
            key = unquote_plus(bytes(key)).decode('utf8')
            value = unquote_plus(bytes(value)).decode('utf8')
            elements[key] = value
        # do stuff with elements...
        for item in elements.iteritems():
            print '"%s" = "%s"' % item
        QtGui.qApp.quit()


# setup the html form
html = """
<form action="" method="get">
Like it?
<input type="radio" name="like" value="yes"/> Yes
<input type="radio" name="like" value="no" /> No
<br/><input type="text" name="text" value="" />
<input type="submit" name="submit" value="Send"/>
</form>
"""

html2 = """
<form action="" method="get">
Choose wisely?
<input type="radio" name="choose" value="A"/> Yes
<input type="radio" name="choose" value="B" /> No
<br/><input type="text" name="text" value="" />
<input type="submit" name="submit" value="Send"/>
</form>
"""

def main():
    app = QtGui.QApplication(sys.argv)
    intro = PsyTML()
    intro.viewPsyTML(html)
    # now, the html form is displayed nicely and the form elemtns returned
    app.exec_()
    # do something else here

    # in the secomd run, the form is not submitted.
    intro.viewPsyTML(html2)
    app.exec_()



if __name__ == "__main__":
    main()

我正在使用Python 2。

Answer 1

需要更改程序的当前结构。

首先，main函数应尽可能简单。它应该只创建一个应用程序对象和一个主窗口，然后运行事件循环。在那之后，一切都应该围绕信号/事件及其处理程序构建。

目前，只有一个中心事件：表单提交。这发生异步，因此应用程序必须保存其当前状态，然后被动地等待每个表单完成，然后才能继续执行下一个任务。

修改

既然您的规范更清晰，实现目标的一种方法是使用QDialog，它有自己的事件循环。

以下是您的脚本的修订版本，希望更接近您想要的内容：

import sys from urllib import unquote_plus from PyQt4 import QtCore, QtGui, QtWebKit class MyWebPage(QtWebKit.QWebPage): formSubmitted = QtCore.pyqtSignal(object) def acceptNavigationRequest(self, frame, req, nav_type): if nav_type == QtWebKit.QWebPage.NavigationTypeFormSubmitted: elements = {} for key, value in req.url().encodedQueryItems(): key = unquote_plus(bytes(key)).decode('utf8') value = unquote_plus(bytes(value)).decode('utf8') elements[key] = value self.formSubmitted.emit(elements) return super(MyWebPage, self).acceptNavigationRequest(frame, req, nav_type) class PsyTML(QtGui.QDialog): def __init__(self): super(PsyTML, self).__init__() self.elements = {} self.view = QtWebKit.QWebView(self) layout = QtGui.QVBoxLayout(self) layout.addWidget(self.view) layout.setContentsMargins(0, 0, 0, 0) self.view.setPage(MyWebPage()) self.view.page().formSubmitted.connect(self.handleFormSubmitted) def viewPsyTML(self, html): self.view.setHtml(html) self.exec_() def handleFormSubmitted(self, elements): self.elements = elements self.accept() # setup the html form html = """ <form action="" method="get"> Like it? <input type="radio" name="like" value="yes"/> Yes <input type="radio" name="like" value="no" /> No <br/><input type="text" name="text" value="" /> <input type="submit" name="submit" value="Send"/> </form> """ html2 = """ <form action="" method="get"> Choose wisely? <input type="radio" name="choose" value="A"/> Yes <input type="radio" name="choose" value="B" /> No <br/><input type="text" name="text" value="" /> <input type="submit" name="submit" value="Send"/> </form> """ def main(): app = QtGui.QApplication(sys.argv) intro = PsyTML() intro.viewPsyTML(html) # do stuff with elements... for item in intro.elements.iteritems(): print '"%s" = "%s"' % item intro = PsyTML() intro.viewPsyTML(html2) if __name__ == "__main__": main()

PyQt4：重启主循环？

1 个答案: