在json解析中，如何从后退按钮的子类别中获取先前的类别?

I am new to iphone development. I am developing one iphone application like as sms collection from json parsing in that application having first category list like as funny sms, love sms in UITableview when click love sms then i get list love sms in uitablview ....after click particular love sms then i display that particular sms in view ...but my problem is when click back option from love sms to main category it's reponse slow my back button code is I am new to iphone development. I am developing