python - 生成 QCloseEvent 不会关闭 QMainWindow

Question

我正在尝试做一些非常简单的事情:添加一个带有 Exit 操作的菜单栏，该操作将在选择时关闭 QMainWindow 。但是，当我实际单击 Exit 时，它不会关闭应用程序。 SSCCE:

from PyQt4 import QtGui, QtCore

import sys

class Window(QtGui.QMainWindow):

    def __init__(self, parent=None):
        super(Window, self).__init__(parent)
        widget = QtGui.QWidget()
        self.setCentralWidget(widget)

        self.menu_bar = QtGui.QMenuBar(self)
        menu = self.menu_bar.addMenu('File')

        exit_action = QtGui.QAction('Exit', self)
        exit_action.triggered.connect(lambda:
            self.closeEvent(QtGui.QCloseEvent()))
        menu.addAction(exit_action)
        self.setMenuBar(self.menu_bar)

    def closeEvent(self, event):
        print('Calling')
        print('event: {0}'.format(event))
        event.accept()


app = QtGui.QApplication(sys.argv)
form = Window()
form.show()
sys.exit(app.exec_())

真正让我困惑的是，当我从 File 菜单中单击 Exit 时，我得到以下输出:

Calling

event: <PyQt4.QtGui.QCloseEvent object at 0x024B7348>

并且应用程序不会退出。

如果我点击右上角的X，我会得到同样的结果(直到事件对象的相同内存地址):

Calling

event: <PyQt4.QtGui.QCloseEvent object at 0x024B7348>

并且应用程序确实退出。

此版本适用于 Windows 7 64 位、Python 2.7.2、PyQt 4.8.6。

Answer 1

文档says ,

The QCloseEvent class contains parameters that describe a close event.

Close events are sent to widgets that the user wants to close, usually by choosing "Close" from the window menu, or by clicking the X title bar button. They are also sent when you call QWidget.close() to close a widget programmatically.

您可以直接使用信号关闭来调用，而不是通过QCloseEvent来调用，请调用self.close()。

from PyQt4 import QtGui, QtCore

import sys

class Window(QtGui.QMainWindow):

    def __init__(self, parent=None):
        super(Window, self).__init__(parent)
        widget = QtGui.QWidget()
        self.setCentralWidget(widget)

        self.menu_bar = QtGui.QMenuBar(self)
        menu = self.menu_bar.addMenu('File')

        exit_action = QtGui.QAction('Exit', self)
        exit_action.triggered.connect(self.close)
        menu.addAction(exit_action)
        self.setMenuBar(self.menu_bar)

    def closeEvent(self, event):
        print('Calling')
        print('event: {0}'.format(event))
        event.accept()


app = QtGui.QApplication(sys.argv)
form = Window()
form.show()
sys.exit(app.exec_())