QMimeData 类具有处理丢弃 url 的方法.下面是一个最小的工作示例:

The QMimeData class has methods for dealing with dropped urls. Below is a minimal working example:

# from PyQt4.QtGui import QApplication, QLabel
# from PySide2.QtWidgets import QApplication, QLabel
from PyQt5.QtWidgets import QApplication, QLabel

class Window(QLabel):
    def __init__(self):
        super().__init__()
        self.setAcceptDrops(True)

    def dragEnterEvent(self, event):
        print('drag-enter')
        if event.mimeData().hasUrls():
            print('has urls')
            event.accept()
        else:
            event.ignore()

    def dropEvent(self, event):
        lines = []
        for url in event.mimeData().urls():
            lines.append('dropped: %r' % url.toLocalFile())
        self.setText('
'.join(lines))
    
app = QApplication(['Drag & Drop'])
window = Window()
window.setGeometry(50, 100, 400, 300)
window.show()
app.exec_()

更新:

关于问题的补充:

一些小部件(与上面使用的 QLabel 不同)有一个默认的 dragMoveEvent 实现，它明确地忽略大多数事件.例如，基于 QAbstractItemView 的类可能只处理某些类型的内部移动而忽略其他所有内容.在这种情况下，应添加重新实现 dragMoveEvent 以明确接受需要以不同方式处理的事件:

Some widgets (unlike the QLabel used above) have a default implementation of dragMoveEvent that explicitly ignores most events. For example, classes based on QAbstractItemView may only handle certain kinds of internal move and ignore everything else. In which case, a reimplementation of dragMoveEvent should be added that explicitly accepts the events that need to be handled differently:

class MyView(QTableView):
    ...
    def dragMoveEvent(self, event):
        if event.mimeData().hasUrls():
            event.accept()
        else:
            super().dragMoveEvent(event)