#! /usr/bin/python
# -*- coding: UTF-8 -*-

import sys
from PyQt4 import QtCore, QtGui

class TreeComboBox(QtGui.QComboBox):
    def __init__(self, parent=None):
        super(QtGui.QComboBox, self).__init__(parent)
        self._skipNextHide = False
        self._treeView = QtGui.QTreeView(self)
        self.setView(self._treeView)
        self._treeView.header().hide()
        self._treeView.viewport().installEventFilter(self)

    def eventFilter( self, object, event):
        if event.type() == QtCore.QEvent.MouseButtonPress and object == self.view().viewport():
            index = self.view().indexAt(event.pos())
            if not self.view().visualRect(index).contains(event.pos()):
                self._skipNextHide = True
        return False

    def showPopup(self):
        self.setRootModelIndex(QtCore.QModelIndex())
        self._treeView.expandAll()
        QtGui.QComboBox.showPopup(self)

    def hidePopup(self):
        if self._skipNextHide:
            self._skipNextHide = False
        else:
            self.setRootModelIndex(self.view().currentIndex().parent())
            self.setCurrentIndex(self.view().currentIndex().row())
            QtGui.QComboBox.hidePopup(self)

class Main(QtGui.QWidget):
    def __init__(self, parent=None):
        QtGui.QWidget.__init__(self, parent)

        self._comboBox = TreeComboBox(self)
        self._treeView = QtGui.QTreeView(self)

        layout = QtGui.QVBoxLayout()
        layout.addWidget(self._comboBox)
        layout.addWidget(self._treeView)
        self.setLayout(layout)

        model = QtGui.QStandardItemModel()
        for a in range(3):
            i = QtGui.QStandardItem('Item ' + str(a))
            for b in range(3):
                ii = QtGui.QStandardItem('sub 1 Item ' + str(b))
                i.setChild(b, ii)
                for c in range(3):
                    iii = QtGui.QStandardItem('sub 2 Item ' + str(c))
                    ii.setChild(c, iii)
            model.appendRow(i)

        self._comboBox.setModel(model)
        self._treeView.setModel(model)

        self.connect(self._treeView, QtCore.SIGNAL("clicked(const QModelIndex&)"), self.comboSelect)

    def comboSelect(self, idx):
        self._comboBox.setRootModelIndex(idx.parent())
        self._comboBox.setCurrentIndex(idx.row())

if __name__ == "__main__":
    app = QtGui.QApplication(sys.argv)

    main = Main()
    main.show()

    sys.exit(app.exec_())