那时您开始搜索时，可以创建活动指标，并使用addSubView方法将其添加为UISearchBar的subview. >

When you start searching at that time you can create an activity indicator and add it as the subview of UISearchBar using addSubView method.

  UIActivityIndicatorView *spinner = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleGray];

//set your frame for activity indicator

[searchBar addSubview: spinner];

[spinner startAnimating];

完成搜索后，请使用removeFromSuperView方法将其从搜索栏中删除.

When you finish the search remove it from the search bar using removeFromSuperView method.