why uislider calling a method twice?

i have set an ibaction(touch up inside) to uislider.when i slide th开发者_JS百科e slider and moves my finger up it is called twice.anyone knows about it? or if someone knows about how to call a method when lifting finger up from uislider.Note i have already a method(Value changed) bound to uislider

UISlider has one interesting property. It calls continuous. If you need to process only the final value, you can try to set it to NO.