//推断是否ios7 取消控制拉升
if ([[UIDevice currentDevice].systemVersion doubleValue] >= 7.0) {
self.edgesForExtendedLayout = UIRectEdgeNone;
}
//推断是否ios7 取消控制拉升
if ([[UIDevice currentDevice].systemVersion doubleValue] >= 7.0) {
self.edgesForExtendedLayout = UIRectEdgeNone;
}