IOS中搜索框UISearchBar及搜索方法的使用

搜索框可以用UISearchBar，并且可以设置代理UISearchBarDelegate。

-(void)addSearchBar{
    CGRect searchBarRect = CGRectMake(0, 0, self.view.frame.size.width, 44);
    UISearchBar *searchBar = [[UISearchBar alloc]initWithFrame:searchBarRect];
    searchBar.placeholder = @"plrase enter key word";
    self.tableView.tableHeaderView = searchBar;
    //设置搜索框旁边的取消按钮
    searchBar.showsCancelButton = YES;
    //设置搜索范围
    searchBar.showsScopeBar = YES;
    searchBar.scopeButtonTitles = [NSArray arrayWithObjects:@"姓名",@"性别",@"学号", nil];
    //代理
    searchBar.delegate = self;
}

效果如图：

对结果搜索的处理也不是很麻烦，原理就是字符串中是否包含搜索的关键字，然后刷新tableView

//contact.firstName为所有数据，keyWord为搜索的关键字
if ([contact.firstName.uppercaseString containsString:keyWord.uppercaseString]) {
    [_searchContacts addObject:contact];
}

实现代理可以用

#pragma mark 搜索框代理
#pragma mark 取消搜索
-(void)searchBarCancelButtonClicked:(UISearchBar *)searchBar{
    //放弃第一响应者对象，关闭软键盘
    [self.searchBar resignFirstResponder];
}

#pragma mark 输入搜索关键字
-(void)searchBar:(UISearchBar *)searchBar textDidChange:(NSString *)searchText{
    
}

#pragma mark 点击虚拟键盘上的搜索时
-(void)searchBarSearchButtonClicked:(UISearchBar *)searchBar{
    [self.searchBar resignFirstResponder];
}

效果如下：

也可以用更简单的UISearchDisplayController，它内部有一个UITableView类型的对象searchResultsTableView，就可以不用上边的3个代理了。只需实现1个。UISearchDisplayController在使用UINavavigationController时还可以自动全屏，效果为

#pragma mark - UISearchDisplayController代理方法
-(BOOL)searchDisplayController:(UISearchDisplayController *)controller shouldReloadTableForSearchString:(NSString *)searchString{
    [self searchDataWithKeyWord:searchString];
    return YES;
}

添加UISearchDisplayController时，有两种写法。需要注意，否则会报
Property 'searchDisplayController' attempting to use instance variable '_searchDisplayController' declared in super class 'UIViewController'
第一种，用property形式，需要@synthesize修饰才可以

@interface ContactsTableViewController ()<UISearchBarDelegate,UISearchDisplayDelegate>

@property(nonatomic,strong) UISearchBar *searchBar;
@property(nonatomic,strong) UISearchDisplayController *searchDisplayController;

@end

@implementation ContactsTableViewController
//需要用synthesize修饰
@synthesize searchDisplayController;

//此时的添加搜索栏可以用
-(void)addSearchBar{
    _searchBar=[[UISearchBar alloc]init];
    [_searchBar sizeToFit];//大小自适应容器
    _searchBar.placeholder = @"plrase enter key word";
    _searchBar.autocapitalizationType = UITextAutocapitalizationTypeNone;
    _searchBar.showsCancelButton = YES;//显示取消按钮
    _searchBar.delegate=self;
    self.tableView.tableHeaderView=_searchBar;

    self.searchDisplayController = [[UISearchDisplayController alloc]initWithSearchBar:self.searchBar contentsController:self];
    self.searchDisplayController.delegate = self;
    self.searchDisplayController.searchResultsDataSource = self;
    self.searchDisplayController.searchResultsDelegate = self;
    [self.searchDisplayController setActive:NO animated:YES];
}

@end

第二种，用带下划线的形式，无需@synthesize修饰

@interface ContactsTableViewController ()<UISearchBarDelegate,UISearchDisplayDelegate>{
    UISearchDisplayController *_searchDisplayController;
}

@property(nonatomic,strong) UISearchBar *searchBar;

@end

@implementation ContactsTableViewController

//此时添加搜索栏为
-(void)addSearchBar{
    self.searchBar = [[UISearchBar alloc]init];
    [self.searchBar sizeToFit];//大小自适应容器
    self.searchBar.placeholder = @"plrase enter key word";
    self.searchBar.autocapitalizationType = UITextAutocapitalizationTypeNone;
    self.searchBar.showsCancelButton = YES;//显示取消按钮
    self.searchBar.delegate=self;
    self.tableView.tableHeaderView = self.searchBar;
    
    _searchDisplayController = [[UISearchDisplayController alloc]initWithSearchBar:self.searchBar contentsController:self];
    _searchDisplayController.delegate = self;
    _searchDisplayController.searchResultsDataSource = self;
    _searchDisplayController.searchResultsDelegate = self;
    [_searchDisplayController setActive:NO animated:YES];
}

@end