def _openFile(self):
        """Opens a file dialog and sets a value for the QLineEdit widget.

        This method is also a `SLOT`.

        """

        file_types = "Comma Separated Values (*.csv);;Text files (*.txt);;All Files (*)"
        ret = QtGui.QFileDialog.getOpenFileName(self,
                                                self.tr('open file'),
                                                filter=file_types)

        if isinstance(ret, tuple):
            ret = ret[0] #PySide compatibility maybe?

        if ret:
            self._filenameLineEdit.setText(ret)
            self._updateFilename()
Opens a file dialog and sets a value for the QLineEdit widget.

        This method is also a `SLOT`.