Thanks, i achieved it with this:

for testcases in root.iter('testcase'):
testcase_name = QtGui.QApplication.translate(
"qadashboard", str(testcases.attrib), None)
item = QtGui.QListWidgetItem(testcase_name, self.listWidgetTestCases)
item.setFlags(item.flags() | QtCore.Qt.ItemIsUserCheckable)
item.setCheckState(QtCore.Qt.Unchecked)