I contact samsumg honkong for this situation. .and they reply by this
According to your situation, GT-I9235 (Hong Kong model) allows you to open folder to answer the calls. You can follow the below steps to turn on this function.
Settings > My Device > Accessibility > Answering / /ending calls > Open folder to answer > Tick
but it didnt work out..there's noo (OPEN FOLDER TO ANSWER)..ANY WAY ALI..plz if u knew how send and email at email@example.com. ..thx