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PyQt:在基类中重写mousepresessevent方法时,将mousepresessevent传递给原始小部件

pyqt5 pyqt python

Dennis Miller · 技术社区 · 6 年前

我正在尝试为小部件创建一个全局上下文帮助系统。其中所有小部件都可以用ContextHelpBase类进行扩展,并具有向Context Help Display小部件发送信号所需的所有逻辑。

其思想是,当用户单击小部件时,它将显示一些上下文帮助。所以我超载了 mousePressEvent 发送一个信号,但是现在正常的按钮和QComboBox行为不起作用,因为我假设我在重写它之后没有将信号传递给正常的事件处理程序。

from PyQt5.QtWidgets import QApplication, QLabel, QWidget, QPushButton, QComboBox, QHBoxLayout, QVBoxLayout
from PyQt5.QtCore import QObject, pyqtSignal, pyqtSlot

class ContextHelpSignals(QObject):
    """ Used to send signals globally through the application
        Eventually will be a Global Singelton
    """
    textHelp = pyqtSignal(str)

    def __init__(self):
        super(ContextHelpSignals, self).__init__()

#Eventually will be a Global Singleton
_contextHelp = ContextHelpSignals()

class ContextHelpBaseClass(QObject):
    """All Widget that have context help inherits this class"""
    def __init__(self, **kw):
        super(ContextHelpBaseClass, self).__init__()
        self.helpText = None

    def mousePressEvent(self, event):
        """ THIS DISABLE WIDGETS NORMAL CLICK BEHAVIOR """
        _contextHelp.textHelp.emit(self.helpText)
        # How can emit a signal and then pass this event to the normal widget
        print(type(super()))

    def SetHelpText(self, helpText):
        self.helpText = helpText

class ContexHelpDisplay(QLabel):
    """Dislpay Context Help frow widgets that have Context Help"""
    def __init__(self, text):
        super(ContexHelpDisplay, self).__init__()
        self.setText(text)
        _contextHelp.textHelp.connect(self.__displayHelp)
        # Need to pass event to original widget
        # type.mousePresseEvent() - How do I get type?

    @pyqtSlot(str)
    def __displayHelp(self, contextHelpText):
        self.setText(contextHelpText)

class ContextHelpButton(QPushButton, ContextHelpBaseClass):
    """QPush Button with Context Help"""
    def __init__(self, text):
        super(ContextHelpButton, self).__init__()
        self.setText(text)
        self.helpText = "This is QPushButton Context Help Text"

## It would be nice if I could use a Python Decorator, but
## don't know how yet.
## @ContextHelp
class ContextHelpComboBox(QComboBox, ContextHelpBaseClass):
    """QPush Button with Context Help"""
    def __init__(self):
        super(ContextHelpComboBox, self).__init__()
        self.helpText = "This is QComboBox Context Help Text"

class MainWindow(QWidget):
    def __init__(self, parent=None):
        super(MainWindow, self).__init__(parent=parent)
        self.setupUI()

    def setupUI(self):
        self.resize(250, 150)
        self.setWindowTitle('Context Help Example')
        self.show()

        button = ContextHelpButton("Test Button")

        comboBox = ContextHelpComboBox()
        comboBox.addItem("Test Item 1")
        comboBox.addItem("Test Item 2")
        comboBox.addItem("Test Item 3")

        helpTextDisplay = ContexHelpDisplay("Context Help")

        vBox = QVBoxLayout()
        vBox.addWidget(button)
        vBox.addWidget(comboBox)

        hBox = QHBoxLayout()
        hBox.addLayout(vBox)
        hBox.addWidget(helpTextDisplay)

        self.setLayout(hBox)

if __name__ == "__main__":
    app = QApplication([])
    ex = MainWindow()
    exit(app.exec_())

主要问题 :

其他问题 :

对于Python装饰器,这可能吗
有没有更好的设计模式更适合这种情况?

3 回复 | 直到 6 年前

S. Nick 6 年前

@eyllanesc所说的可能是这样的:

from PyQt5.QtWidgets import (QApplication, QLabel, QWidget, QPushButton, 
                             QComboBox, QHBoxLayout, QVBoxLayout)
from PyQt5.QtCore    import QObject, pyqtSignal, pyqtSlot,  QEvent, Qt


class ContextHelpSignals(QObject):
    """ Used to send signals globally through the application
        Eventually will be a Global Singelton                """
    textHelp = pyqtSignal(str)

    def __init__(self):
        super(ContextHelpSignals, self).__init__()


# Eventually will be a Global Singleton
_contextHelp = ContextHelpSignals()


class ContextHelpBaseClass(QObject):   
    """ All Widget that have context help inherits this class """
    def __init__(self, **kw):
        super(ContextHelpBaseClass, self).__init__()
        self.helpText = None

    def mousePressEvent(self, event):
        ''' THIS DISABLE WIDGETS NORMAL CLICK BEHAVIOR '''
        _contextHelp.textHelp.emit(self.helpText)
        # How can emit a signal and then pass this event to the normal widget
        print(type(super()))

    def SetHelpText(self, helpText):              # ???
        self.helpText = helpText


class ContexHelpDisplay(QLabel):
    """Dislpay Context Help frow widgets that have Context Help"""
    def __init__(self, text):
        super(ContexHelpDisplay, self).__init__()
        self.setText(text)
        _contextHelp.textHelp.connect(self.__displayHelp)
        # Need to pass event to original widget
        # type.mousePresseEvent() - How do I get type?

    @pyqtSlot(str)
    def __displayHelp(self, contextHelpText):
        self.setText(contextHelpText)

class ContextHelpButton(QPushButton, ContextHelpBaseClass):
    """QPush Button with Context Help"""
    def __init__(self, text):
        super(ContextHelpButton, self).__init__()
        self.setText(text)
        self.helpText = "This is <b>QPushButton</b> Context Help Text"


class ContextHelpComboBox(QComboBox):             # - --> , ContextHelpBaseClass):
    """QPush Button with Context Help"""
    def __init__(self):
        super(ContextHelpComboBox, self).__init__()
        self.helpText = "This is <b>QComboBox</b> Context Help Text"


class MainWindow(QWidget):
    def __init__(self, parent=None):
        super(MainWindow, self).__init__(parent=parent)
        self.setupUI()

    def setupUI(self):
        self.resize(250, 150)
        self.setWindowTitle('Context Help Example')
        self.show()

        button = ContextHelpButton("Test Button")

        self.comboBox = ContextHelpComboBox()     # + self.
        self.comboBox.addItem("Test Item 1")
        self.comboBox.addItem("Test Item 2")
        self.comboBox.addItem("Test Item 3")

        self.comboBox.installEventFilter(self)    # <- Installs an event filter filterObj on this object. 

        self.helpTextDisplay = ContexHelpDisplay("Context Help")

        vBox = QVBoxLayout()
        vBox.addWidget(button)
        vBox.addWidget(self.comboBox)

        hBox = QHBoxLayout()
        hBox.addLayout(vBox)
        hBox.addWidget(self.helpTextDisplay)
        self.setLayout(hBox)

    # Filters events if this object has been installed as an event filter for the watched object.
    def eventFilter(self, obj, event):
        if event.type() == QEvent.MouseButtonPress and obj is self.comboBox:
            self.helpTextDisplay.setText(self.comboBox.helpText)
        return super(MainWindow, self).eventFilter(obj, event)


if __name__ == "__main__":
    app = QApplication([])
    ex  = MainWindow()
    exit(app.exec_())

Dennis Miller 6 年前

作为后续工作,我通过在基类中存储子类的引用,然后使用该引用传递事件,实现了我想要的目标。

from PyQt5.QtWidgets import (QApplication, QLabel, QWidget, QPushButton,
                             QComboBox, QHBoxLayout, QVBoxLayout)
from PyQt5.QtCore    import QObject, pyqtSignal, pyqtSlot

class ContextHelpSignals(QObject):
    """ Used to send signals globally through the application
        Eventually will be a Global Singleton                """
    textHelp = pyqtSignal(str)

    def __init__(self):
        super(ContextHelpSignals, self).__init__()

# Eventually will be a Global Singleton
_contextHelp = ContextHelpSignals()

class ContexHelpDisplay(QLabel):
    """Display Context Help from widgets that have Context Help"""
    def __init__(self, text):
        super(ContexHelpDisplay, self).__init__()
        self.setText(text)
        _contextHelp.textHelp.connect(self.__displayHelp)

    @pyqtSlot(str)
    def __displayHelp(self, contextHelpText):
        self.setText(contextHelpText)

class ContextHelpBaseClass(QObject):
    """ All Widget that have context help inherits this class """
    def __init__(self, childObject):
        super(ContextHelpBaseClass, self).__init__()
        self.helpText = None
        self.childObject = childObject
        print( type(childObject) )

    def mousePressEvent(self, event):
        _contextHelp.textHelp.emit(self.helpText)
        # Pass mouse click event to native widget
        self.childObject.mousePressEvent(event)

class ContextHelpButton(QPushButton, ContextHelpBaseClass):
    """QPush Button with Context Help"""
    def __init__(self, text):
        super(ContextHelpButton, self).__init__(self)
        self.setText(text)
        self.helpText = "This is <b>QPushButton</b> Context Help Text"

    def test(self):
        print("BUTTON")

class ContextHelpComboBox(QComboBox, ContextHelpBaseClass):
    """QPush Button with Context Help"""
    def __init__(self):
        super(ContextHelpComboBox, self).__init__(self)
        self.helpText = "This is <b>QComboBox</b> Context Help Text"

    def test(self):
        print("Combo Box")

class MainWindow(QWidget):
    def __init__(self, parent=None):
        super(MainWindow, self).__init__(parent=parent)
        self.setupUI()

    def setupUI(self):
        self.resize(250, 150)
        self.setWindowTitle('Context Help Example')
        self.show()

        button = ContextHelpButton("Test Button")

        comboBox = ContextHelpComboBox()
        comboBox.addItem("Test Item 1")
        comboBox.addItem("Test Item 2")
        comboBox.addItem("Test Item 3")

        helpTextDisplay = ContexHelpDisplay("Context Help")

        button.clicked.connect(button.test)

        vBox = QVBoxLayout()
        vBox.addWidget(button)
        vBox.addWidget(comboBox)

        hBox = QHBoxLayout()
        hBox.addLayout(vBox)
        hBox.addWidget(helpTextDisplay)
        self.setLayout(hBox)

if __name__ == "__main__":
    app = QApplication([])
    ex  = MainWindow()
    exit(app.exec_())

Dennis Miller 6 年前

from PyQt5.QtWidgets import (QApplication, QLabel, QWidget, QPushButton,
                             QComboBox, QHBoxLayout, QVBoxLayout)
from PyQt5.QtCore    import QObject, pyqtSignal, pyqtSlot

def ContextHelp(text):
    """Decorates a class by adding mousePressEvent method"""
    def AddMouseClickEventDecorator(_class):
        """ Adds 'mousePressEvent()' method to class"""
        def mousePressEvent(self, event):
            _contextHelp.textHelp.emit(text)       #Emit a signal to global ContextHelp Singleton
            super(_class, self).mousePressEvent(event) #Call Widget Base Class event

        #Add 'mousePressEvent' to _class
        setattr(_class, 'mousePressEvent', mousePressEvent)
        return _class #Decorated class
    return AddMouseClickEventDecorator



class ContextHelpSignals(QObject):
    """ Used to send signals globally through the application
        Eventually will be a Global Singleton                """
    textHelp = pyqtSignal(str)

    def __init__(self):
        super(ContextHelpSignals, self).__init__()

# Eventually will be a Global Singleton
_contextHelp = ContextHelpSignals()

class ContexHelpDisplay(QLabel):
    """Display Context Help from widgets that have Context Help"""
    def __init__(self, text):
        super(ContexHelpDisplay, self).__init__()
        self.setText(text)
        _contextHelp.textHelp.connect(self.__displayHelp)

    @pyqtSlot(str)
    def __displayHelp(self, contextHelpText):
        self.setText(contextHelpText)

@ContextHelp("This is a push button")
class ContextHelpButton(QPushButton):
    """QPush Button with Context Help"""
    def __init__(self, text):
        super(ContextHelpButton, self).__init__()
        self.setText(text)

@ContextHelp("This is Combo Box")
class ContextHelpComboBox(QComboBox):
    """QPush Button with Context Help"""
    def __init__(self):
        super(ContextHelpComboBox, self).__init__()


class MainWindow(QWidget):
    def __init__(self, parent=None):
        super(MainWindow, self).__init__(parent=parent)
        self.setupUI()

    def setupUI(self):
        self.resize(250, 150)
        self.setWindowTitle('Context Help Example')
        self.show()

        button = ContextHelpButton("Test Button")

        comboBox = ContextHelpComboBox()
        comboBox.addItem("Test Item 1")
        comboBox.addItem("Test Item 2")
        comboBox.addItem("Test Item 3")

        helpTextDisplay = ContexHelpDisplay("Context Help")

        button.clicked.connect(self.TestButton)

        vBox = QVBoxLayout()
        vBox.addWidget(button)
        vBox.addWidget(comboBox)

        hBox = QHBoxLayout()
        hBox.addLayout(vBox)
        hBox.addWidget(helpTextDisplay)
        self.setLayout(hBox)

    def TestButton(self):
        print("Button Pressed.")

if __name__ == "__main__":
    app = QApplication([])
    ex  = MainWindow()
    exit(app.exec_())