iOS11是个分界岭
self.extendedLayoutIncludesOpaqueBars = YES;
if (@available(iOS 11.0, *)) {
self.tableView.contentInsetAdjustmentBehavior = UIScrollViewContentInsetAdjustmentNever;
} else {
self.automaticallyAdjustsScrollViewInsets = NO;
}
_tableView.contentInset = UIEdgeInsetsMake(64, 0, 49, 0);
_tableView.scrollIndicatorInsets = _tableView.contentInset;