PyQt5 窗口文件拖拽setAcceptDrops（把文件拖拽进widget） 

   def __init__(self):
        self.setAcceptDrops(True)
    def dragEnterEvent(self, event):
        extensions = [
            ".%s" % fmt.data().decode().lower()
            for fmt in QtGui.QImageReader.supportedImageFormats()
        if event.mimeData().hasUrls():
            items = [i.toLocalFile() for i in event.mimeData().urls()]
            print(items)
            if any([i.lower().endswith(tuple(extensions)) for i in items]):
                event.accept()
        else:
            event.ignore() 
    def dropEvent(self, event):
        print("拖拽结束",dir(event))
        if not self.mayContinue():