PySide：可移動項目的位置在鼠標事件時重置

Question

我對PySide有問題（我仍然是編程方面的新手）。 我創建了名為RBNode的自定義QGraphicsItem。 它應保持在發生mouseReleaseEvent的位置。 我不知道為什么，但是當我嘗試多次移動RBNode類的實例時，此實例的位置將重置。 如何避免重置位置？ 在此先感謝您的幫助。

#!/usr/bin/python
# -*- coding: utf-8 -*-

import sys
from PySide.QtGui import *
from PySide.QtCore import *

class RBNode(QGraphicsItem):
    def __init__(self, factorView = None):
        super(RBNode, self).__init__()
        self.factor = factorView
        self.pressed = False
        self.x = self.pos().x()
        self.y = self.pos().y()
        self.setFlag(QGraphicsItem.ItemIsMovable)

    def boundingRect(self):
        return QRectF(-50,-50,100,100)

    def paint(self, painter, option, widget):
        rect = QRectF(-50,-50,100,100)

        if self.pressed:
            painter.setBrush(Qt.red)
        else:
            painter.setBrush(Qt.darkGray)

        painter.drawEllipse(rect)

    def mousePressEvent(self, event):
        self.pressed = True
        self.update()
        QGraphicsItem.mousePressEvent(event)

    def mouseReleaseEvent(self, event):
        self.pressed = False
        self.update()
        QGraphicsItem.mouseReleaseEvent(event)


class RBGraphicView(QGraphicsView):
    def __init__(self):
        super(RBGraphicView, self).__init__()
        self.factorView = 1

        self.initScene()
        self.initGui()

    def initGui(self):
        self.setWindowTitle("A Simple Animation")
        self.show()

    def initScene(self):
        self.rbScene = QGraphicsScene(self)
        self.rbAddItem(self.rbScene)
        self.setScene(self.rbScene)

    def rbAddItem(self, scene):

        rbNode1 = RBNode(self.factorView)
        rbNode1.setPos(100,100)
        scene.addItem(rbNode1)


if __name__ == '__main__':
    try:
        myApp = QApplication(sys.argv)
        myView = RBGraphicView()
        myApp.exec_()
        sys.exit(0)

    except NameError:
        print("Name Error:", sys.exc_info()[1])

    except SystemExit:
        print("Closing Window...")

    except Exception:
        print(sys.exc_info()[1])

Answer 1

您在對超類的mousePressEvent和mouseReleaseEvent的調用中忘記了作為參數的自身。

    QGraphicsItem.mousePressEvent(self, event)

    QGraphicsItem.mouseReleaseEvent(self, event)