drop_signal_to_parent.py

from PySide.QtGui import *
from PySide.QtCore import *


class MainWindow(QWidget):
    def __init__(self):
        super(MainWindow, self).__init__()
        self.ly = QVBoxLayout(self)
        self.setLayout(self.ly)
        self.list = ListClass()
        self.ly.addWidget(self.list)

        # 2 - connect custom signal
        self.list.itemDroppedSignal.connect(self.add_new_item)

    def add_new_item(self, url):
        print url
        item = QListWidgetItem()
        item.setText(url)
        self.list.addItem(item)


class ListClass(QListWidget):
    # 1 - create custom signal
    itemDroppedSignal = Signal(object)

    def __init__(self):
        super(ListClass, self).__init__()
        self.setAcceptDrops(True)

    def dropEvent(self, event):
        mime = event.mimeData()
        if mime.hasUrls():
            for url in mime.urls():
                
                # 3 - emit custom signal
                self.itemDroppedSignal.emit(url.toLocalFile())
                
                # self.add_item(url.toLocalFile())

    def dragEnterEvent(self, event):
        event.accept()

    def dragMoveEvent(self, event):
        event.accept()

    def add_item(self, path):
        item = QListWidgetItem()
        item.setText(path)
        self.addItem(item)


if __name__ == '__main__':
    app = QApplication([])
    w = MainWindow()
    w.show()
    app.exec_()