在QStackedWidget，pyqt中设置stateChanged信号

Question

我有一个来自互联网的QStacked Widget代码的例子，它为每个子级生成自己的布局（下面）

import sys
from PyQt4.QtCore import *
from PyQt4.QtGui import *
class stackedExample(QWidget):
    def __init__(self):
        super(stackedExample, self).__init__()
        self.leftlist = QListWidget()
        self.leftlist.insertItem(0, 'Contact')
        self.leftlist.insertItem(1, 'Personal')
        self.leftlist.insertItem(2, 'Educational')
        self.stack1 = QWidget()
        self.stack2 = QWidget()
        self.stack3 = QWidget()
        self.stack1UI()
        self.stack2UI()
        self.stack3UI()
        self.Stack = QStackedWidget(self)
        self.Stack.addWidget(self.stack1)
        self.Stack.addWidget(self.stack2)
        self.Stack.addWidget(self.stack3)
        hbox = QHBoxLayout(self)
        hbox.addWidget(self.leftlist)
        hbox.addWidget(self.Stack)
        self.setLayout(hbox)
        self.leftlist.currentRowChanged.connect(self.display)
        self.setGeometry(300, 50, 10, 10)
        self.setWindowTitle('StackedWidget demo')
        self.show()
    def stack1UI(self):
        layout = QFormLayout()
        layout.addRow("Name", QLineEdit())
        layout.addRow("Address", QLineEdit())
        # self.setTabText(0,"Contact Details")
        self.stack1.setLayout(layout)
    def stack2UI(self):
        layout = QFormLayout()
        sex = QHBoxLayout()
        sex.addWidget(QRadioButton("Male"))
        sex.addWidget(QRadioButton("Female"))
        layout.addRow(QLabel("Sex"), sex)
        layout.addRow("Date of Birth", QLineEdit())
        self.stack2.setLayout(layout)
    def stack3UI(self):
        layout = QHBoxLayout()
        layout.addWidget(QLabel("subjects"))
        layout.addWidget(QCheckBox("Physics"))
        layout.addWidget(QCheckBox("Maths"))
        self.stack3.setLayout(layout)
    def state_changed(self):
        pass
    def display(self, i):
        self.Stack.setCurrentIndex(i)

def main():
    app = QApplication(sys.argv)
    ex = stackedExample()
    sys.exit(app.exec_())

if __name__ == '__main__':
    main()

现在我想收集所有这些数据，并在以后进行处理。例如，我如何知道选中了哪个复选框？此代码layout.addWidget（QCheckBox（"Physics"）.stateChanged.connect（self.state_changed））

给我

进程已完成，退出代码为1073741819（0xC0000005）

Answer 1

当您编写时

layout.addWidget(QCheckBox("Physics").stateChanged.connect(self.state_changed))

它不会查找Physics复选框，但会创建一个新的复选框。因为您没有保留对它的Python引用，所以在离开构造函数后，它将被销毁。然而，它仍然与信号相连，从而导致不可预测的行为。

如果你想连接到原始复选框，你需要对其进行引用

import sys
from PyQt4.QtCore import *
from PyQt4.QtGui import *
class stackedExample(QWidget):
    def __init__(self):
        super(stackedExample, self).__init__()
        self.leftlist = QListWidget()
        self.leftlist.insertItem(0, 'Contact')
        self.leftlist.insertItem(1, 'Personal')
        self.leftlist.insertItem(2, 'Educational')
        self.stack1 = QWidget()
        self.stack2 = QWidget()
        self.stack3 = QWidget()
        self.stack1UI()
        self.stack2UI()
        self.stack3UI()
        # Renamed self.stack to self.stack since the convention is to start
        # class names with a capital but regular variables with a lower case.
        self.stack = QStackedWidget(self) 
        self.stack.addWidget(self.stack1)
        self.stack.addWidget(self.stack2)
        self.stack.addWidget(self.stack3)
        hbox = QHBoxLayout(self)
        hbox.addWidget(self.leftlist)
        hbox.addWidget(self.stack)
        self.setLayout(hbox)
        self.leftlist.currentRowChanged.connect(self.display)
        self.setGeometry(300, 50, 10, 10)
        self.setWindowTitle('StackedWidget demo')
        self.show()
    def stack1UI(self):
        layout = QFormLayout()
        layout.addRow("Name", QLineEdit())
        layout.addRow("Address", QLineEdit())
        # self.setTabText(0,"Contact Details")
        self.stack1.setLayout(layout)
    def stack2UI(self):
        layout = QFormLayout()
        sex = QHBoxLayout()
        sex.addWidget(QRadioButton("Male"))
        sex.addWidget(QRadioButton("Female"))
        layout.addRow(QLabel("Sex"), sex)
        layout.addRow("Date of Birth", QLineEdit())
        self.stack2.setLayout(layout)
    def stack3UI(self):
        layout = QHBoxLayout()
        layout.addWidget(QLabel("subjects"))
        self.physicsCheckBox = QCheckBox("Physics")
        layout.addWidget(self.physicsCheckBox)
        self.physicsCheckBox.stateChanged.connect(self.physicsCheckBoxStateChanged)
        layout.addWidget(QCheckBox("Maths"))
        self.stack3.setLayout(layout)

    def physicsCheckBoxStateChanged(self, state):
        isChecked = bool(state) # Convert from Qt.CheckState
        print("physicsCheckBox: {}".format(isChecked))
    def display(self, i):
        self.stack.setCurrentIndex(i)

def main():
    app = QApplication(sys.argv)
    ex = stackedExample()
    sys.exit(app.exec_())

if __name__ == '__main__':
    main()

附言：我把self.Stack改名为self.stack。Python惯例是让类定义以大写字符和正则变量开头，函数以小写字母开头。