从转态栏开始布局
self.edgesForExtendedLayout = UIRectEdgeAll;
self.automaticallyAdjustsScrollViewInsets=NO;
/**
- (void)automaticallyAdjustsScrollViewInsets{
if ([[[UIDevice currentDevice] systemVersion] floatValue] > 6.9) {
[super setAutomaticallyAdjustsScrollViewInsets:flag];
}
*/