pyqt5设置主窗体MainWindow背景图片

#基本框架
from PyQt5.QtGui import QPainter, QPixmap

#主要代码段
class QmyMainWindow(QMainWindow):
    def __init__(self,parent=None):
        super().__init__(parent)

        self.setAutoFillBackground(True)
        self.__pic=QPixmap("bg.jpg")

    def paintEvent(self,event):
        painter=QPainter(self)
        painter.drawPixmap(0,self.ui.toolBar.height(),self.width(),self.height()-self.ui.toolBar.height()-self.ui.statusbar.height(),self.__pic)
        super().paintEvent(event)