Question

我有以下文件（主窗口/ UI）： files

UI：

# -*- coding: utf-8 -*-

# Form implementation generated from reading ui file 'mainwindow.ui'
#
# Created: Sat Apr 23 15:53:12 2011
#     by: PyQt4 UI code generator 4.7.3
#
# WARNING! All changes made in this file will be lost!

from PyQt4 import QtCore, QtGui

class Ui_MainWindow(object):
    ### Presetting Model ###
    model = QtGui.QFileSystemModel()
    def setupUi(self, MainWindow):
        MainWindow.setObjectName("MainWindow")
        MainWindow.resize(1000, 600)    
        self.centralWidget = QtGui.QWidget(MainWindow)
        self.centralWidget.setObjectName("centralWidget")
        self.horizontalLayout_2 = QtGui.QHBoxLayout(self.centralWidget)
        self.horizontalLayout_2.setObjectName("horizontalLayout_2")
        self.horizontalLayout = QtGui.QHBoxLayout()
        self.horizontalLayout.setObjectName("horizontalLayout")
        self.treeView = QtGui.QTreeView(self.centralWidget)
        sizePolicy = QtGui.QSizePolicy(QtGui.QSizePolicy.Expanding, QtGui.QSizePolicy.Expanding)
        sizePolicy.setHorizontalStretch(2)
        sizePolicy.setVerticalStretch(0)
        sizePolicy.setHeightForWidth(self.treeView.sizePolicy().hasHeightForWidth())
        self.treeView.setSizePolicy(sizePolicy)
        self.treeView.setHeaderHidden(True)
        self.treeView.setObjectName("treeView")
        self.horizontalLayout.addWidget(self.treeView)
        self.plainTextEdit = QtGui.QPlainTextEdit(self.centralWidget)
        sizePolicy = QtGui.QSizePolicy(QtGui.QSizePolicy.Expanding, QtGui.QSizePolicy.Expanding)
        sizePolicy.setHorizontalStretch(4)
        sizePolicy.setVerticalStretch(0)
        sizePolicy.setHeightForWidth(self.plainTextEdit.sizePolicy().hasHeightForWidth())
        self.plainTextEdit.setSizePolicy(sizePolicy)
        self.plainTextEdit.setObjectName("plainTextEdit")
        self.horizontalLayout.addWidget(self.plainTextEdit)
        self.horizontalLayout_2.addLayout(self.horizontalLayout)
        MainWindow.setCentralWidget(self.centralWidget)
        ### MENU ###
        self.menuBar = QtGui.QMenuBar(MainWindow)
        self.menuBar.setGeometry(QtCore.QRect(0, 0, 600, 27))
        self.menuBar.setObjectName("menuBar")
        MainWindow.setMenuBar(self.menuBar)

        ### Setting up tree view model ###
        self.treeView.setModel(self.model)
        self.treeView.setSelectionMode(QtGui.QAbstractItemView.ExtendedSelection)
#       self.treeView.setRootIndex(self.model.setRootPath(Xmldocument.directorypath))

        ### Hiding additional info in treeview ###
        hHeader = self.treeView.header()
        hHeader.hideSection(1)
        hHeader.hideSection(2)
        hHeader.hideSection(3)

        MainWindow.setWindowTitle(QtGui.QApplication.translate("MainWindow", "VeloCondDB Browser", None, QtGui.QApplication.UnicodeUTF8))
        QtCore.QMetaObject.connectSlotsByName(MainWindow)

##############################################################

    def __del__(self):
        print "DESTRUCTOR"

主窗口：

import sys
import os

from browserclass_UI import Ui_MainWindow
from PyQt4 import QtCore, QtGui

class Browser(QtGui.QMainWindow):

#############################################################################################

    def __init__(self, parent=None):
        """Constructor for the main window."""

        QtGui.QWidget.__init__(self, parent)

        self.ui = Ui_MainWindow()
        self.ui.setupUi(self)

        menuitems = ["Open", "Close"]
        menu = self.ui.menuBar.addMenu('File')
        for item in menuitems:
            entry = menu.addAction(item)
            self.connect(entry, QtCore.SIGNAL('triggered()'), lambda item=item: self.doStuff(item)) 

#############################################################################################

    def doStuff(self, item):
        print item

#############################################################################################

if __name__ == "__main__":
    browser = QtGui.QApplication(sys.argv)
    myapp = Browser()
    myapp.show()
    sys.exit(browser.exec_())

来自以下行：

的菜单项...

到

... self.connect

没有注释

，永远不会调用来自UI的析构函数。如果他们被评论一切正常。有什么想法吗？

Answer 1

您不能依赖__del__为所有对象调用，尤其是当您的程序结束时（请参阅that other answer）

根据PyQt documentation：

但是，如果一个槽是lambda函数或部分函数那么它的引用计数自动递增以防止它立即被垃圾收集。

当你连接lambda函数的信号时，可能会创建对Browser对象的一些循环引用，这就是防止它被销毁的原因。由ui引用Browser，它也不会被销毁。

因此，当这些插槽是lambda函数时，您必须手动断开插槽。或使用除lambda之外的其他方法将额外参数绑定到插槽（例如QSignalMapper，或将QAction作为参数的QMenu.triggered信号）：

def __init__(self, parent):
    ...
    for item in menuitems:
        entry = menu.addAction(item)
    menu.triggered.connect(self.doStuff)

def doStuff(self, entry):
    print entry.text()

添加qmenubar后不会调用析构函数

UI：

主窗口：

1 个答案: