搜索框的代理方法

• (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