code: def on_open_input_tool_clicked(self):
          
          input_path = self.input_path.text()
          if not input_path:
              input_path = os.path.expanduser('~')
          # noinspection PyCallByClass,PyTypeChecker
          filename, __ = QFileDialog.getOpenFileName(
              self, tr('Input file'), input_path, tr('Raw grid file (*.xml)'))
          if filename:
              self.input_path.setText(filename)
docs: Autoconnect slot activated when open input tool button is clicked.