Question

在我的应用程序中，我有一个QGraphicsScene，用户应该可以通过单击鼠标按钮并将鼠标悬停在项目上来更改项目的颜色。

以下是我从另一个问题中借用的示例代码：

PyQt: hover and click events for graphicscene ellipse

from PyQt5 import QtGui, QtCore, QtWidgets

class MyFrame(QtWidgets.QGraphicsView):
    def __init__( self, parent = None ):
        super(MyFrame, self).__init__(parent)

        self.setScene(QtWidgets.QGraphicsScene())

        # add some items
        x = 0
        y = 0
        w = 15
        h = 15
        pen = QtGui.QPen(QtGui.QColor(QtCore.Qt.green))
        brush = QtGui.QBrush(pen.color().darker(150))

        # i want a mouse over and mouse click event for this ellipse
        for xi in range(3):
            for yi in range(3):
                item = callbackRect(x+xi*30, y+yi*30, w, h)
                item.setAcceptHoverEvents(True)
                item.setPen(pen)
                item.setBrush(brush)
                self.scene().addItem(item)
                item.setFlag(QtWidgets.QGraphicsItem.ItemIsMovable)

class callbackRect(QtWidgets.QGraphicsRectItem):
    '''
    Rectangle call-back class.
    '''

    def mouseReleaseEvent(self, event):
        # recolor on click
        color = QtGui.QColor(180, 174, 185)
        brush = QtGui.QBrush(color)
        QtWidgets.QGraphicsRectItem.setBrush(self, brush)

        return QtWidgets.QGraphicsRectItem.mouseReleaseEvent(self, event)

    def hoverMoveEvent(self, event):
        # Do your stuff here.
        pass

    def hoverEnterEvent(self, event):
        color = QtGui.QColor(0, 174, 185)
        brush = QtGui.QBrush(color)
        QtWidgets.QGraphicsRectItem.setBrush(self, brush)

    def hoverLeaveEvent(self, event):
        color = QtGui.QColor(QtCore.Qt.green)
        brush = QtGui.QBrush(color.darker(150))
        QtWidgets.QGraphicsRectItem.setBrush(self, brush)

if ( __name__ == '__main__' ):
    app = QtWidgets.QApplication([])
    f = MyFrame()
    f.show()
    app.exec_()

因此，在此代码中，只有在没有按下鼠标按钮时才会调用悬停方法。如文档中所述（对于PySide），mousePressEvent“决定接收鼠标事件的图形项”，这在某种程度上阻止了其他项的鼠标事件。

https://deptinfo-ensip.univ-poitiers.fr/ENS/pyside-docs/PySide/QtGui/QGraphicsItem.html?highlight=graphicsitem#PySide.QtGui.PySide.QtGui.QGraphicsItem.mouseMoveEvent

但是，有没有办法同时按住鼠标按钮并调用不同项目的悬停事件？

Answer 1

问题是使任务变得复杂的事件组合，您可以传播mouseMoveEvent事件，但是您不能对悬停事件执行相同操作。一个简单的解决方案是在mouseMoveEvent的方法QGraphicsView中实现逻辑，如下所示：

class MyFrame(QtWidgets.QGraphicsView):
    def __init__( self, parent = None ):
        super(MyFrame, self).__init__(parent)    
        self.setScene(QtWidgets.QGraphicsScene())
        [...]

    itemsSelected = []
    def mouseMoveEvent(self, event):
        QtWidgets.QGraphicsView.mouseMoveEvent(self, event)
        items = self.items(event.pos())#, QtGui.QTransform())
        for item in self.itemsSelected:
            if item in items:
                item.enterColor()
            else:
                item.leaveColor()
        self.itemsSelected = items

class callbackRect(QtWidgets.QGraphicsRectItem):
    '''
    Rectangle call-back class.
    '''
    def enterColor(self):
        color = QtGui.QColor(0, 174, 185)
        brush = QtGui.QBrush(color)
        QtWidgets.QGraphicsRectItem.setBrush(self, brush)

    def leaveColor(self):
        color = QtGui.QColor(QtCore.Qt.green)
        brush = QtGui.QBrush(color.darker(150))
        QtWidgets.QGraphicsRectItem.setBrush(self, brush)

    def hoverEnterEvent(self, event):
        self.enterColor()

    def hoverLeaveEvent(self, event):
        self.leaveColor()

在PyQt中单击时悬停事件

1 个答案: