检测wxpython中的拖动

import wx

class DraggableWindow(wx.Frame):
    def __init__(self, parent, title):
        super(DraggableWindow, self).__init__(parent, title=title, size=(300, 200))
        self.Centre()
        self.Bind(wx.EVT_LEFT_DOWN, self.OnMouseDown)
        self.Bind(wx.EVT_MOTION, self.OnMouseMove)

        self.dragging = False
        self.drag_start_pos = (0, 0)

    def OnMouseDown(self, event):
        self.dragging = True
        self.drag_start_pos = (event.GetX(), event.GetY())

    def OnMouseMove(self, event):
        if self.dragging:
            x, y = event.GetPosition()
            dx = x - self.drag_start_pos[0]
            dy = y - self.drag_start_pos[1]
            self.Move(self.GetPosition()[0] + dx, self.GetPosition()[1] + dy)
            self.drag_start_pos = (x, y)

app = wx.App(False)
frame = DraggableWindow(None, 'Draggable Window')
frame.Show(True)
app.MainLoop()