A issue about input data check for ALV OO when click 'save' button twice

Hello, colleagues

I have a issue about input data check for ALV OO when click 'save' button twice.

I put data check coding in 'handle_data_changed' method.

When I save at the first time, calling  'check_data_changed' method after PAI event and 'handle_data_changed' method is triggered, and messages is displayed for error input data.

Then I click the 'save' button again without correct the error input data, because no data is changed so 'handle_data_changed' method is not triggered, but the error data is saved.

Do you know how to resolve this issue?

Thanks a lot in advance!

Best regards,

Daniel