UISearchDisplay Delegate的12个方法的调用顺序
UISearchBar所在的viewController
（以下简称mainVC）的- (void)viewDidLoad方法中的代码如下：
//
[superviewDidLoad];
//searchBar
self.searchBar = [[UISearchBaralloc] init];
self.searchBar.frame =CGRectMake(0,0, self.view.frame.size.width,44);
self.searchBar.delegate =self;
self.searchBar.placeholder =@"搜索";
//SearchDisplayController
self.searchVC = [[UISearchDisplayControlleralloc] initWithSearchBar:self.searchBarcontentsController:self];
self.searchVC.delegate =self;
self.searchVC.searchResultsTableView.backgroundColor =BACKGROUND_COLOR;
self.searchVC.searchResultsTableView.separatorStyle =UITableViewCellSeparatorStyleNone;
self.searchVC.searchResultsTableView.rowHeight = GAP_OF_VIEWS+AVATAR_WIDTH+GAP_OF_VIEWS;
self.searchVC.searchResultsDataSource =self;
self.searchVC.searchResultsDelegate =self;
//显示主界面tableView
self.mainTableView = [[UITableViewalloc] init];
self.mainTableView.frame =CGRectMake(0,0, self.view.frame.size.width,self.view.frame.size.height-49-44);
self.mainTableView.dataSource =self;
self.mainTableView.delegate =self;
self.mainTableView.backgroundColor =BACKGROUND_COLOR;
self.mainTableView.separatorStyle =UITableViewCellSeparatorStyleNone;
self.mainTableView.rowHeight =GAP_OF_VIEWS+AVATAR_WIDTH+GAP_OF_VIEWS;
[self.viewaddSubview:_mainTableView];
self.mainTableView.tableHeaderView =self.searchBar;
一、运行完self.searchVC.searchResultsTableView.backgroundColor =BACKGROUND_COLOR 这句，就会触发
1、 - (void)searchDisplayController:(UISearchDisplayController *)controller didLoadSearchResultsTableView:(UITableView *)tableView // called when the table is created destroyed, shown or hidden. configure as necessary.
继续运行，mainVC的界面就显示出来了。
二、点击searchBar的输入区域，就会依次触发
2、- (BOOL)searchBarShouldBeginEditing:(UISearchBar *)searchBar // return NO to not become first responder
3、- (void)searchBarTextDidBeginEditing:(UISearchBar *)searchBar // called when text starts editing
4、- (void) searchDisplayControllerWillBeginSearch:(UISearchDisplayController *)controller // when we start/end showing the search UI
此时，search UI就会全屏显示出来，键盘也弹起了
5、- (void) searchDisplayControllerDidBeginSearch:(UISearchDisplayController *)controller
点击键盘上的一个按钮
6、- (BOOL)searchBar:(UISearchBar *)searchBar shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text // called before text changes
再点击键盘上的一个按钮，仍然调用step6的方法；再点击键盘上的一个按钮，仍然调用step6的方法，这时候可以选中一个汉字，就会触发
7、- (void)searchBar:(UISearchBar *)searchBar textDidChange:(NSString *)searchText //called when text changes (including clear)
8、- (BOOL)searchDisplayController:(UISearchDisplayController *)controller shouldReloadTableForSearchString:(NSString *)searchString // return YES to reload table. called when search string/option changes. convenience methods on top UISearchBar delegate methods
9、- (void)searchDisplayController:(UISearchDisplayController *)controller willShowSearchResultsTableView:(UITableView *)tableView //called when table is shown/hidden
10、- (void)searchDisplayController:(UISearchDisplayController *)controller didShowSearchResultsTableView:(UITableView *)tableView
此时就会显示搜索结果，再输入，会重复step6－8
如果此时点击键盘上的“搜索”按钮，会触发
11、- (void)searchBarSearchButtonClicked:(UISearchBar *)searchBar // called when keyboard search button pressed
12、- (BOOL)searchBarShouldEndEditing:(UISearchBar *)searchBar // return NO to not resign first responder
13、- (void)searchBarTextDidEndEditing:(UISearchBar *)searchBar // called when text ends editing
这时UISearchBar中的文字输入框会失去焦点，键盘就会消失
如果此时点击UISearchBar文字输入框最右边的x来清除输入的话，会触发step7、8以及
14、- (void)searchDisplayController:(UISearchDisplayController *)controller willHideSearchResultsTableView:(UITableView *)tableView
15、- (void)searchDisplayController:(UISearchDisplayController *)controller didHideSearchResultsTableView:(UITableView *)tableView
又开始调用step2、3，界面看起来就像刚才进入search UI全屏界面时的样子，可以再次重复以上操作
当然，可以点击右上角的“取消／cancel”按钮，就会触发
16、- (void)searchBarCancelButtonClicked:(UISearchBar *) searchBar //called when cancel button pressed
17、- (void) searchDisplayControllerWillEndSearch:(UISearchDisplayController *)controller
18、- (void)searchDisplayController:(UISearchDisplayController *)controller willHideSearchResultsTableView:(UITableView *)tableView
19、- (void)searchDisplayController:(UISearchDisplayController *)controller didHideSearchResultsTableView:(UITableView *)tableView
20、- (void)searchDisplayController:(UISearchDisplayController *)controller willUnloadSearchResultsTableView:(UITableView *)tableView
21、- (void) searchDisplayControllerDidEndSearch:(UISearchDisplayController *)controller