In the code sample below I have found a problem with changing cursors.

Basically I have a MyScene with two MyRect items shown with a MyView.

In the view I change "modes" by pressing F1 - F3. To visually represent the modes I want to change the cursor of the view (background) and the items.

If I do not move the mouse cursor over items the cursor of the view changes fine. As soon as I move the cursors over the items, the item cursors change ok but the view cursor does not change or changes wrong.

Is this a bug or am I doing something wrong here?

Qt Code: 
  1. from PyQt4.QtCore import *
  2. from PyQt4.QtGui import *
  3.  
  4. class MyRect(QGraphicsRectItem):
  5.  
  6.     def __init__(self, parent=None, scene=None):
  7.         # init parent
  8.         super().__init__(parent, scene)
  9.  
  10.         # set flags
  11.         self.setFlag(QGraphicsItem.ItemIsSelectable, True)
  12.         self.setFlag(QGraphicsItem.ItemIsMovable, True)
  13.         self.setFlag(self.ItemSendsGeometryChanges, True)
  14.         self.setAcceptHoverEvents(True)
  15.  
  16.     def paint(self, painter, option, widget):
  17.         if self.isSelected():
  18.             painter.setPen(QPen(Qt.black, 1, Qt.DotLine))
  19.         else:            
  20.             painter.setPen(QPen(Qt.black, 1, Qt.SolidLine))
  21.  
  22.         painter.setBrush(QBrush(Qt.white, Qt.SolidPattern))
  23.         painter.drawRect(self.rect())
  24.  
  25. class MyView(QGraphicsView):
  26.  
  27.     def __init__(self, parent=None):
  28.         super().__init__(parent)
  29.         self.setMouseTracking(True)
  30.         self.scale(1,1)
  31.         self.startPos = None
  32.  
  33.     def setSelectMode(self):
  34.         print("view setting select mode")
  35.         self.scene().setViewMode(MyScene.SELECTMODE)
  36.  
  37.     def setEditMode(self):
  38.         print("view setting edit mode")
  39.         self.scene().setViewMode(MyScene.EDITMODE)
  40.         if len(self.scene().selectedItems()) > 1:
  41.             self.scene().clearSelection()
  42.  
  43.     def setDrawMode(self):
  44.         print("view setting draw mode")
  45.         self.scene().setViewMode(MyScene.DRAWMODE)
  46.         self.scene().clearSelection()
  47.  
  48.     def updateItems(self):
  49.         print("view updateItems")
  50.         m = self.scene().viewMode()
  51.  
  52.         if m == MyScene.SELECTMODE:
  53.             print("is select mode")
  54.             self.setCursor(Qt.ArrowCursor)
  55.             print(self.cursor().shape())
  56.             #self.update()
  57.             itemCursor = Qt.OpenHandCursor
  58.  
  59.         elif m == MyScene.EDITMODE:
  60.             print("is edit mode")
  61.             self.setCursor(Qt.ForbiddenCursor)
  62.             print(self.cursor().shape())
  63.             #self.update()
  64.             itemCursor = Qt.PointingHandCursor
  65.  
  66.         elif m == MyScene.DRAWMODE:
  67.             print("is draw mode")
  68.             self.setCursor(Qt.CrossCursor)
  69.             print(self.cursor().shape())
  70.             #self.update()
  71.             itemCursor = Qt.WaitCursor
  72.  
  73.         items = self.scene().items()
  74.  
  75.         for item in items:
  76.             item.setCursor(itemCursor)
  77.             #item.update()
  78.  
  79.     def drawBackground(self, painter, rect):
  80.         # draw a rect in size of sceneRect
  81.  
  82.         painter.setPen(QPen(Qt.red, 0, Qt.NoPen))
  83.         painter.setBrush(QBrush(Qt.lightGray, Qt.SolidPattern))                
  84.         painter.drawRect(self.scene().sceneRect())        
  85.  
  86.     def mousePressEvent(self, mouseEvent):
  87.         print("view mousePress")
  88.         curPos = mouseEvent.pos()
  89.         self.startPos = self.mapToScene(curPos)
  90.  
  91.         if self.scene().viewMode() == MyScene.DRAWMODE:
  92.             self.scene().newItem = MyRect(scene=self.scene())
  93.             self.scene().newItem.setRect(QRectF(self.startPos, QSizeF(0, 0)))
  94.             self.scene().newItem.setSelected(True)
  95.  
  96.         else:
  97.             super().mousePressEvent(mouseEvent)
  98.  
  99.     def mouseMoveEvent(self, mouseEvent):
  100.         #print("view mouseMove")
  101.         curPos = self.mapToScene(mouseEvent.pos())
  102.  
  103.         if self.scene().viewMode() == MyScene.DRAWMODE:
  104.             if self.scene().newItem:
  105.                 newRectF = QRectF(self.startPos, curPos)
  106.                 if newRectF != self.scene().newItem.rect():
  107.                     self.scene().newItem.setRect(newRectF.normalized())
  108.  
  109.         else:
  110.             super().mouseMoveEvent(mouseEvent)
  111.  
  112.     def mouseReleaseEvent(self, mouseEvent):
  113.         print("view mouseRelease")
  114.  
  115.         if self.scene().newItem:
  116.             # delete item if zero height or width
  117.             if (self.scene().newItem.rect().width() == 0 
  118.                 or self.scene().newItem.rect().height() == 0):
  119.                 self.scene().removeItem(self.scene().newItem)
  120.                 del self.scene().newItem
  121.  
  122.         self.startPos = None
  123.         self.scene().newItem = None
  124.         super().mouseReleaseEvent(mouseEvent)
  125.  
  126.     def keyPressEvent(self, keyEvent):
  127.         if keyEvent.key() == Qt.Key_F1:
  128.             self.setSelectMode()
  129.             self.updateItems()
  130.  
  131.         elif keyEvent.key() == Qt.Key_F2:
  132.             self.setEditMode()
  133.             self.updateItems()
  134.  
  135.         elif keyEvent.key() == Qt.Key_F3:
  136.             self.setDrawMode()
  137.             self.updateItems()
  138.  
  139.         elif keyEvent.key() == Qt.Key_Delete:
  140.             if self.scene().viewMode() == MyScene.SELECTMODE:
  141.                 items = self.scene().selectedItems()
  142.                 if len(items):
  143.                     for item in items:
  144.                         self.scene().removeItem(item)
  145.                         del item                   
  146.  
  147. class MyScene(QGraphicsScene):
  148.  
  149.     SELECTMODE, EDITMODE, DRAWMODE = (0, 1, 2)
  150.     validViewModes = [SELECTMODE, EDITMODE, DRAWMODE]
  151.  
  152.     def __init__(self, parent=None):
  153.         super().__init__(parent)
  154.  
  155.         self._viewMode = MyScene.SELECTMODE
  156.         self.newItem = None
  157.  
  158.         self.setSceneRect(-300, -200, 600, 400)
  159.  
  160.         # add some item
  161.         someRect = MyRect(scene=self)
  162.         someRect.setRect(QRectF(0, 0, 160, 80))
  163.  
  164.         # add another item
  165.         anotherRect = MyRect(scene=self)
  166.         anotherRect.setRect(QRectF(-80, -40, 80, 160))
  167.  
  168.         # add own item
  169.         #myItem = MyItem(scene=self)
  170.  
  171.     def setViewMode(self, value):
  172.         if value != self._viewMode:
  173.             if value in MyScene.validViewModes:
  174.                 self._viewMode = value
  175.             else:
  176.                 raise ValueError("invalid view mode")
  177.  
  178.     def viewMode(self):
  179.         return self._viewMode
  180.  
  181. class MainWindow(QMainWindow):
  182.  
  183.     def __init__(self, parent=None):
  184.         # call parent init
  185.         super().__init__(parent)
  186.  
  187.         # setup scene object
  188.         self.scene = MyScene()
  189.  
  190.         # setup view object
  191.         self.view = MyView()
  192.  
  193.         # connect scene to view
  194.         self.view.setScene(self.scene)
  195.  
  196.         # create layout
  197.         layout = QVBoxLayout()
  198.  
  199.         # add view to layout
  200.         layout.addWidget(self.view)
  201.  
  202.         # set the margin of the object in the layout
  203.         layout.setContentsMargins(0, 0, 0, 0)
  204.  
  205.         # create the central widget
  206.         self.widget = QWidget()
  207.  
  208.         # lay it out
  209.         self.widget.setLayout(layout)
  210.  
  211.         # set it to central
  212.         self.setCentralWidget(self.widget)        
  213.  
  214. if __name__ == "__main__":
  215.  
  216.     import sys
  217.  
  218.     # setup application object
  219.     app = QApplication(sys.argv)
  220.  
  221.     # create (parent) main window
  222.     mainWindow = MainWindow()
  223.     mainWindow.setWindowTitle("testScene")
  224.     mainWindow.show()
  225.  
  226.     # run application object
  227.     sys.exit(app.exec_())
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