python - Pyside2 我怎样才能移动盒子？

Question

如果我按下左键移动鼠标，我想移动我的 SimpleItem 对象。如果我按下对象，我已经成功地获得了鼠标光标的位置。但我不知道如何将项目移动到那个位置。你能帮帮我吗？

import sys
from PySide2 import QtGui, QtWidgets, QtCore


class SimpleItem(QtWidgets.QGraphicsItem):
    def __init__(self):
        QtWidgets.QGraphicsItem.__init__(self)
        self.location = 1.0

    def boundingRect(self):
        penWidth = 1.0
        return QtCore.QRectF(-10 - penWidth / 2, -10 - penWidth / 2,
                      20 + penWidth, 20 + penWidth)

    def paint(self, painter, option, widget):
        rect = self.boundingRect()
        painter.drawRect(rect)

    def mousePressEvent(self, event):
        print("hello")

    def mouseMoveEvent(self, event):
        print(event.pos())


if __name__ == "__main__":
    app = QtWidgets.QApplication(sys.argv)
    scene = QtWidgets.QGraphicsScene()
    item = SimpleItem()
    scene.addItem(item)
    view = QtWidgets.QGraphicsView(scene)
    view.show()
    sys.exit(app.exec_())

Answer 1

对于QGraphicsXXXItem，无需覆盖任何方法来启用移动，启用标志QGraphicsItem::ItemIsMovable 就足够了。 .

import sys
from PySide2 import QtGui, QtWidgets, QtCore


class SimpleItem(QtWidgets.QGraphicsItem):
    def __init__(self):
        QtWidgets.QGraphicsItem.__init__(self)
        self.setFlag(QtWidgets.QGraphicsItem.ItemIsMovable, True)

    def boundingRect(self):
        penWidth = 1.0
        return QtCore.QRectF(-10 - penWidth / 2, -10 - penWidth / 2,
                      20 + penWidth, 20 + penWidth)

    def paint(self, painter, option, widget):
        rect = self.boundingRect()
        painter.drawRect(rect)


if __name__ == "__main__":
    app = QtWidgets.QApplication(sys.argv)
    scene = QtWidgets.QGraphicsScene()
    item = SimpleItem()
    scene.addItem(item)
    view = QtWidgets.QGraphicsView(scene)
    view.show()
    sys.exit(app.exec_())