let poptime=dispatch_time(DISPATCH_TIME_NOW ,Int64(0.2 * Double(NSEC_PER_SEC)))
dispatch_after(poptime,dispatch_get_main_queue() , { () -> Void in
self._bannerscroll .contentOffset=CGPointMake(self._bannerscroll.frame.size.width,0)
})
dispatch_after(poptime,dispatch_get_main_queue() , { () -> Void in
self._bannerscroll .contentOffset=CGPointMake(self._bannerscroll.frame.size.width,0)
})