pythonpyqt：如何用鼠标移动窗口上的小部件？

我是Python新手。我用固定坐标画了多边形和圆。现在我想用鼠标将这个多边形和圆移动到窗口上的其他位置。请指导我怎么做

import sys
from PyQt4.QtGui import *
from PyQt4.QtCore import *

class MyFrame(QWidget):
    def __init__(self, parent=None):
            QWidget.__init__(self)

    def paintEvent(self, event=None):
            paint=QPainter(self)
            paint.setPen(QPen(QColor(Qt.green).dark(150),1,Qt.SolidLine))
            segColor=QColor(Qt.green).dark(150)
            paint.setBrush(segColor)
            paint.setBrushOrigin(QPoint(225,225))
            polygon=QPolygon([QPoint(250,175), QPoint(265,175), QPoint(250,190), QPoint(265,190),QPoint(250,175)])
            paint.drawPolygon(polygon)
            paint.setPen(QPen(QColor(Qt.red),1,Qt.SolidLine))
            paint.setBrush(QBrush(Qt.NoBrush))
            polygon1=QPolygon([QPoint(250,300), QPoint(250,500), QPoint(350,500), QPoint(350,300)])
            paint.drawPolyline(polygon1)
            paint.drawEllipse(50,50,50,50)


app=QApplication(sys.argv)
f=MyFrame()
f.show()
app.exec_()

---

您应该查看QGraphicsView，而不是您正在做的事情，它已经内置了这一切

编辑：显示如何创建QPainterPath

from PyQt4 import QtGui, QtCore

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

        scene = QtGui.QGraphicsScene()
        self.setScene(scene)

        # add some items
        x = 0
        y = 0
        w = 45
        h = 45
        pen   = QtGui.QPen(QtGui.QColor(QtCore.Qt.green))
        brush = QtGui.QBrush(pen.color().darker(150))

        item = scene.addEllipse(x, y, w, h, pen, brush)
        item.setFlag(QtGui.QGraphicsItem.ItemIsMovable)

        # create an open path
        path = QtGui.QPainterPath()
        path.moveTo(-w, -h)
        path.lineTo(-w, h)
        path.lineTo(w, h)
        path.lineTo(w, -h)

        clr   = QtGui.QColor('blue')
        clr.setAlpha(120)
        brush = QtGui.QBrush(clr)
        pen   = QtGui.QPen(QtCore.Qt.NoPen)
        fill_item = scene.addRect(-w, y, w*2, h, pen, brush)
        path_item = scene.addPath(path)

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

---

受Eric答案的启发，这里有一些代码通过更新点的x和y坐标来设置点的动画

from PyQt5.QtGui  import QPen, QBrush, QColor
from PyQt5.QtCore import Qt, QTimer
from PyQt5.QtWidgets import QGraphicsView, QGraphicsScene, QGraphicsItem, QApplication

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

        self.sx = 635
        self.sy = 475

        scene = QGraphicsScene(0,0,self.sx,self.sy)
        self.setScene(scene)

        self.x = 0
        self.y = 0
        self.w = 30
        self.h = 30
        pen   = QPen(QColor('dodgerblue'))
        #pen   = QPen(QColor(Qt.green))
        brush = QBrush(pen.color())
        #brush = QBrush(pen.color().darker(150))

        # As opposed to using QPen and QBrush, this colors the periphery only
        #dot = scene.addEllipse(self.x, self.y, self.w, self.h, QColor('dodgerblue')) 

        self.dot = scene.addEllipse(self.x, self.y, self.w, self.h, pen, brush)
        self.dot.setFlag(QGraphicsItem.ItemIsMovable)


if  __name__ == '__main__':
    import sys

    fps = 50
    refresh_period = 1000/fps # ms

    app = QApplication(sys.argv)

    gw = GameWindow()
    gw.resize(640,480)
    gw.show()


    # if the steps match the gw aspect ratio, the dot will move along the main diagonal,
    # otherwise the dot will drift
    xstep = 4
    ystep = 3
    #ystep = xstep * gw.sy / gw.sx

    def moveDot():
       # In place of the next four lines, one can have a function 
       # or a feed from an external source to update gw.x and gw.y
       gw.x += xstep
       gw.x %= gw.sx

       gw.y += ystep
       gw.y %= gw.sy

       gw.dot.setRect(gw.x,gw.y,gw.w,gw.h)

    timer = QTimer()
    timer.timeout.connect(moveDot)

    # Comment this line out to be able to click and drag the dot
    timer.start(refresh_period)

    sys.exit(app.exec_())

---

谢谢Eric的宝贵回复，但这解决了我的部分问题。实际上，我想画一个水箱，我觉得应该用多段线来画，因为我需要三条边，而不是顶部。“QGraphicscene”对象没有属性“addPolyline”。第二，我想根据我的价值给油箱加满油。我怎样才能装满水箱（让我们看看蓝色）？您可以控制场景中的对象-它们不必是简单的形状对象。首先，我将介绍QGraphicsPathItem，它允许您定义要绘制的任何QPainterPath，并支持填充。对于比这更复杂的项目，您可以将任何QGraphicsItem子类化，以使您接近并实现您自己的paintEvent方法。添加路径的快捷方式是QGraphicscene.addPathEric我已尝试按照您的建议进行操作，但我无法为使用QGraphicscene中的PainterPath编写的多段线添加代码。请你发送一些小代码来添加这个。其次，如何保存小部件的位置，因为当我关闭窗口时，所有小部件都会返回到它们的初始位置（我想保存小部件的新位置）？我用一个示例更新了代码，说明了如何创建QPainterPath，就像您所看到的那样。至于保存位置，您需要将它们记录到某个位置的设置中-您可以通过执行scene.items（）循环对象，并通过执行item.pos（）获得每个项目的位置

from PyQt5.QtGui  import QPen, QBrush, QColor
from PyQt5.QtCore import Qt, QTimer
from PyQt5.QtWidgets import QGraphicsView, QGraphicsScene, QGraphicsItem, QApplication

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

        self.sx = 635
        self.sy = 475

        scene = QGraphicsScene(0,0,self.sx,self.sy)
        self.setScene(scene)

        self.x = 0
        self.y = 0
        self.w = 30
        self.h = 30
        pen   = QPen(QColor('dodgerblue'))
        #pen   = QPen(QColor(Qt.green))
        brush = QBrush(pen.color())
        #brush = QBrush(pen.color().darker(150))

        # As opposed to using QPen and QBrush, this colors the periphery only
        #dot = scene.addEllipse(self.x, self.y, self.w, self.h, QColor('dodgerblue')) 

        self.dot = scene.addEllipse(self.x, self.y, self.w, self.h, pen, brush)
        self.dot.setFlag(QGraphicsItem.ItemIsMovable)


if  __name__ == '__main__':
    import sys

    fps = 50
    refresh_period = 1000/fps # ms

    app = QApplication(sys.argv)

    gw = GameWindow()
    gw.resize(640,480)
    gw.show()


    # if the steps match the gw aspect ratio, the dot will move along the main diagonal,
    # otherwise the dot will drift
    xstep = 4
    ystep = 3
    #ystep = xstep * gw.sy / gw.sx

    def moveDot():
       # In place of the next four lines, one can have a function 
       # or a feed from an external source to update gw.x and gw.y
       gw.x += xstep
       gw.x %= gw.sx

       gw.y += ystep
       gw.y %= gw.sy

       gw.dot.setRect(gw.x,gw.y,gw.w,gw.h)

    timer = QTimer()
    timer.timeout.connect(moveDot)

    # Comment this line out to be able to click and drag the dot
    timer.start(refresh_period)

    sys.exit(app.exec_())