单击PyQt时悬停事件

Question

在我的应用程序中，我有一个QGraphicsScene，用户应该可以通过鼠标按钮单击并悬停在项目上来更改项目的颜色。

下面是一个例子代码，这是我从另一个问题借来的：

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，在这种代码的悬停方法只有当没有按下鼠标键调用。如文档中所述（用于PySide），mousePressEvent“决定它接收鼠标事件的图形项目”，它以某种方式阻止其他项目的鼠标事件。

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，并调用不同的项目的悬停事件？

Answer 1

问题是导致任务复杂的事件组合，您可以传播mouseMoveEvent事件，但您无法对悬停事件执行相同的操作。一个简单的解决方案是实现该方法的QGraphicsViewmouseMoveEvent逻辑如下图所示：

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()