- (BOOL)searchBarShouldBeginEditing:(UISearchBar *)searchBar;
将要开始编辑时的回调，返回为NO，则不能编辑
- (void)searchBarTextDidBeginEditing:(UISearchBar *)searchBar;
已经开始编辑时的回调
- (BOOL)searchBarShouldEndEditing:(UISearchBar *)searchBar;
将要结束编辑时的回调
- (void)searchBarTextDidEndEditing:(UISearchBar *)searchBar;
已经结束编辑的回调
(void)searchBar:(UISearchBar *)searchBar textDidChange:(NSString *)searchText; 编辑文字改变的回调
(BOOL)searchBar:(UISearchBar *)searchBar shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text ;
编辑文字改变前的回调，返回NO则不能加入新的编辑文字
- (void)searchBarSearchButtonClicked:(UISearchBar *)searchBar;
搜索按钮点击的回调
- (void)searchBarBookmarkButtonClicked:(UISearchBar *)searchBar;
书本按钮点击的回调
- (void)searchBarCancelButtonClicked:(UISearchBar *)searchBar;
取消按钮点击的回调
- (void)searchBarResultsListButtonClicked:(UISearchBar *)searchBar;
搜索结果按钮点击的回调
- (void)searchBar:(UISearchBar *)searchBar selectedScopeButtonIndexDidChange:(NSInteger)selectedScope;
搜索栏的附加试图中切换按钮触发的回调
