PyQt4，如何创建当前小部件？

Question

我有一个类来创建PyQt4小部件，另一个类来解析xml以获取输入。我想创建一个UI动态添加按钮到窗口小部件，从传递的xml读取，这不会发生：

import sys

import xml.etree.ElementTree as ET
from PyQt4 import QtGui

ui = None

class userInterface(QtGui.QWidget):
    def __init__(self):
    super(userInterface, self).__init__()

    def getFilesWindow(self):
        self.filesSelected = []
        fDialog = QtGui.QFileDialog.getOpenFileNames(self, 'Open file', '/Learning/Python/substance_XML_reading/', "SBS (*.sbs)")

        for path in fDialog:
            if path:self.filesSelected.append(path)
        return self.filesSelected

class ParseXML():

    def getXMLTags(self,fileList):
        self.tags = []
        if fileList:
            print fileList

        for eachFile in fileList:
            fileToParse = ET.parse(eachFile)
            root = fileToParse.getroot()
            for child in root:
                self.tags.append(child.tag)
        return self.tags

def getSetUI(flist):
    global ui
    if flist:
        tagsForBtns = ParseXML().getXMLTags(flist)
        print tagsForBtns
        for eachitem in tagsForBtns:
            btn = QtGui.QPushButton(ui,eachitem)


def main():
    app = QtGui.QApplication(sys.argv)
    ui = userInterface()
    fileListForUIGen = ui.getFilesWindow() # will return a list of files

    getSetUI(fileListForUIGen) # Parses each file, gets tags, creates buttons and has to add to the current window..NOT WORKING

    ui.show()
    sys.exit(app.exec_())

if __name__ == '__main__':
    main()