UISearchController使用及常见问题处理

项目实战开发过程会经常使用到搜索功能，使用系统提供的控件无疑是最方便最简单的，有时也是遇到问题也是较难解决的，接下来我们来分析下UISearchController使用及常见问题的解决:
1.UISearchController基本使用
初始化UISeachBar

#pragma mark - 创建顶部搜索框
- (UISearchBar *)createSearchBar
{
    WEAKSELF
    SearchGroupMemberListController *searchVC = [[SearchGroupMemberListController alloc]init];
    searchVC.identifierString = @"TT_SearchReplyContact";
    searchVC.definesPresentationContext = YES;
    if (self.navigationController.viewControllers.count > 1) {
        searchVC.isHomePage = NO;
    }else{
        searchVC.isHomePage = YES;
    }
    
    searchVC.searchResultsTableViewCellSelectedBlock = ^(NSIndexPath *indexPath,NSMutableArray *dataArray){
        GroupMemberInfo *groupMemberInfo = (GroupMemberInfo *)dataArray[indexPath.row];
        [weakSelf.delegate replyNickNameFromCell:groupMemberInfo];
        [weakSelf dismissViewControllerAnimated:NO completion:^{
            [weakSelf cancel];
        }];
    };
    
    _mySearchController = [[UISearchController alloc] initWithSearchResultsController:searchVC];
    _mySearchController.delegate = self;
    _mySearchController.searchResultsUpdater = self;//搜索结果代理
    _mySearchController.dimsBackgroundDuringPresentation = YES;
    if (@available(iOS 9.1, *)) {
        _mySearchController.obscuresBackgroundDuringPresentation = NO;
    }
    _mySearchController.hidesNavigationBarDuringPresentation = YES;
    _mySearchController.searchBar.placeholder = @"搜索";
    [_mySearchController.searchBar setValue:@"取消"forKey:@"_cancelButtonText"];
    _mySearchController.searchBar.tintColor = kTextColor_170;
    _mySearchController.searchBar.searchBarStyle = UISearchBarStyleMinimal;
    _mySearchController.searchBar.backgroundColor = kBackgroundColor;
    UITextField *searchField = [_mySearchController.searchBar valueForKey:@"_searchField"];
    searchField.backgroundColor = kSearchBackColor;
    searchField.textColor = kTextColort_238;
    searchField.tintColor = kTextColor_170;
    [_mySearchController.searchBar sizeToFit];
    return _mySearchController.searchBar;
}

2.将searchBar添加到tableView的tableHeaderView上即可

3.UISearchController代理UISearchControllerDelegate

点击searchBar，即将进入搜索模式
- (void)willPresentSearchController:(UISearchController *)searchController
{
      self.replyTableView.hidden = YES;//隐藏底部view
    self.navigationController.navigationBar.translucent = YES;//设置导航栏半透明
    searchController.searchBar.placeholder = @"选择回复的人";//搜索占位符
}
//完全进入搜索模式
- (void)didPresentSearchController:(UISearchController *)searchController
{

}
//点击取消按钮，即将关闭搜索模式
- (void)willDismissSearchController:(UISearchController *)searchController
{
      self.replyTableView.hidden = NO;//取消隐藏
    self.navigationController.navigationBar.translucent = NO;//取消导航栏半透明
    searchController.searchBar.placeholder = @"搜索";
}
//完全关闭搜索模式
- (void)didDismissSearchController:(UISearchController *)searchController
{

}

4.UISearchController搜索结果代理UISearchResultsUpdating

#pragma mark - UISearchResultsUpdating
- (void)updateSearchResultsForSearchController:(UISearchController *)searchController{
     NSString *searchString = searchController.searchBar.text;
    if (!ISNULLSTR(searchString)) {
        if (!ISNULLARRAY(self.searchResultTableDataSource)) {
            [self.searchResultTableDataSource removeAllObjects];
        }
        NSArray *searchResult = [self sortSearchResult:searchString];
        if (!ISNULLARRAY(searchResult)) {
            self.searchResultTableDataSource = [searchResult mutableCopy];
        }
        SearchGroupMemberListController *vc = (SearchGroupMemberListController *)searchController.searchResultsController;
        vc.dataArray = self.searchResultTableDataSource;
        [vc.searchTableView reloadData];
    }
}
//模糊筛选好友
- (NSMutableArray *)sortSearchResult:(NSString *)searchString
{
    if (ISNULLSTR(searchString)) {
        return nil;
    }
    NSPredicate *nickNamePredicate  = [NSPredicate predicateWithFormat:@"user_name CONTAINS[cd] %@",searchString];
    NSPredicate *TTNumPredicate = [NSPredicate predicateWithFormat:@"ttString CONTAINS[cd] %@",searchString];
    NSMutableArray *array = [NSMutableArray arrayWithArray:self.memberListArray];
    
    NSPredicate *predicate = [NSCompoundPredicate orPredicateWithSubpredicates:@[nickNamePredicate, TTNumPredicate]];
    [array filterUsingPredicate:predicate];
    NSSortDescriptor *NameSortDescriptor = [NSSortDescriptor sortDescriptorWithKey:@"user_name"ascending:YES];
    NSArray *Sortarray = [array sortedArrayUsingDescriptors:@[NameSortDescriptor]];
    return  [NSMutableArray arrayWithArray:Sortarray];

5.常见问题总结：
1.取消按钮的中文设置，通过KVC进行修改
[_mySearchController.searchBar setValue:@"取消"forKey:@"_cancelButtonText"];
2.点击搜索结果控制器跳转问题
searchVC.definesPresentationContext = YES;
3.取消searchBar的第一响应后，点击取消按钮无反应
原理是cancleBtn.enable=NO,需要手动设置为YES，具体获取cancleBtn的方法，在网上找找有很多，就不多介绍。