def _on_insert_expression(self):
# Slot raised to insert an expression.
if not isinstance(self._item_widget, QgsLayoutItemBaseWidget):
return
qrcode_item = self._item_widget.layoutObject()
if not qrcode_item:
return
sel_txt = self._value_text_edit.textCursor().selectedText()
# Edit expression text if specified
if sel_txt.startswith('[%') and sel_txt.endswith('%]'):
sel_txt = sel_txt.lstrip('[%')
sel_txt = sel_txt.rstrip('%]')
cov_layer = self._item_widget.coverageLayer()
exp_ctx = qrcode_item.createExpressionContext()
exp_dlg = QgsExpressionBuilderDialog(cov_layer, sel_txt, self,
'generic', exp_ctx)
exp_dlg.setWindowTitle(self.tr('Insert Expression for Barcode Data'))
exp_dlg.setAllowEvalErrors(False)
if exp_dlg.exec_() == QDialog.Accepted:
exp = exp_dlg.expressionText()
if exp:
self._value_text_edit.setPlainText('[%{0}%]'.format(exp))
