iOS UISearchController的使用

在iOS9中，UISearchDisplayController 已经被UISearchController替代。搜索框是一种常用的控件。

假设我们要满足下图的需求，产生100个“数字+三个随机字母”，然后搜索包含某个字母的结果。

那么，该怎么做呢？

#import "ViewController.h"

@interface ViewController ()<UITableViewDelegate,UITableViewDataSource,UISearchControllerDelegate,UISearchResultsUpdating>

//tableView
@property (strong, nonatomic)  UITableView *tableView;

//searchController
@property (strong, nonatomic)  UISearchController *searchController;

//数据源
@property (strong,nonatomic) NSMutableArray  *dataList;

@property (strong,nonatomic) NSMutableArray  *searchList;

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];

    _dataList = [NSMutableArray array];
    _searchList = [NSMutableArray array];

    self.dataList=[NSMutableArray arrayWithCapacity:100];

    //产生100个“数字+三个随机字母”
    for (NSInteger i=0; i<100; i++) {
        [self.dataList addObject:[NSString stringWithFormat:@"%ld%@",(long)i,[self shuffledAlphabet]]];
    }

    _tableView = [[UITableView alloc]initWithFrame:CGRectMake(0, 20,[UIScreen  mainScreen].bounds.size.width ,[UIScreen  mainScreen].bounds.size.height)];

    _tableView.delegate = self;
    _tableView.dataSource = self;
    _tableView.separatorStyle = UITableViewCellSelectionStyleNone;

    //创建UISearchController
    _searchController = [[UISearchController alloc]initWithSearchResultsController:nil];
    //设置代理
    _searchController.delegate = self;
    _searchController.searchResultsUpdater= self;

    //设置UISearchController的显示属性，以下3个属性默认为YES
    //搜索时，背景变暗色
    _searchController.dimsBackgroundDuringPresentation = NO;
    //搜索时，背景变模糊
    _searchController.obscuresBackgroundDuringPresentation = NO;
    //隐藏导航栏
    _searchController.hidesNavigationBarDuringPresentation = NO;

    _searchController.searchBar.frame = CGRectMake(self.searchController.searchBar.frame.origin.x, self.searchController.searchBar.frame.origin.y, self.searchController.searchBar.frame.size.width, 44.0);

    // 添加 searchbar 到 headerview
    self.tableView.tableHeaderView = _searchController.searchBar;

    [self.view addSubview:_tableView];

    // Do any additional setup after loading the view, typically from a nib.
}

//产生3个随机字母
- (NSString *)shuffledAlphabet {

    NSMutableArray * shuffledAlphabet = [NSMutableArray arrayWithArray:@[@"A",@"B",@"C",@"D",@"E",@"F",@"G",@"H",@"I",@"J",@"K",@"L",@"M",@"N",@"O",@"P",@"Q",@"R",@"S",@"T",@"U",@"V",@"W",@"X",@"Y",@"Z"]];

    NSString *strTest = [[NSString alloc]init];
    for (int i=0; i<3; i++) {
        int x = arc4random() % 25;
        strTest = [NSString stringWithFormat:@"%@%@",strTest,shuffledAlphabet[x]];
    }

    return strTest;

}

//设置区域的行数
-(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section{
    if (self.searchController.active) {
        return [self.searchList count];
    }else{
        return [self.dataList count];
    }
}

//返回单元格内容
-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{
    static NSString *flag=@"cell";
    UITableViewCell *cell=[tableView dequeueReusableCellWithIdentifier:flag];
    if (cell==nil) {
        cell=[[UITableViewCell alloc]initWithStyle:UITableViewCellStyleDefault reuseIdentifier:flag];
    }
    if (self.searchController.active) {
        [cell.textLabel setText:self.searchList[indexPath.row]];
    }
    else{
        [cell.textLabel setText:self.dataList[indexPath.row]];
    }
    return cell;
}

#pragma mark - UISearchControllerDelegate代理

//测试UISearchController的执行过程

- (void)willPresentSearchController:(UISearchController *)searchController
{
    NSLog(@"willPresentSearchController");
}

- (void)didPresentSearchController:(UISearchController *)searchController
{
    NSLog(@"didPresentSearchController");
}

- (void)willDismissSearchController:(UISearchController *)searchController
{
    NSLog(@"willDismissSearchController");
}

- (void)didDismissSearchController:(UISearchController *)searchController
{
    NSLog(@"didDismissSearchController");
}

- (void)presentSearchController:(UISearchController *)searchController
{
    NSLog(@"presentSearchController");
}

-(void)updateSearchResultsForSearchController:(UISearchController *)searchController {

    NSLog(@"updateSearchResultsForSearchController");
    NSString *searchString = [self.searchController.searchBar text];
    NSPredicate *preicate = [NSPredicate predicateWithFormat:@"SELF CONTAINS[c] %@", searchString];
    if (self.searchList!= nil) {
        [self.searchList removeAllObjects];
    }
    //过滤数据
    self.searchList= [NSMutableArray arrayWithArray:[_dataList filteredArrayUsingPredicate:preicate]];
    //刷新表格
    [self.tableView reloadData];
}

UISearchController代理方法的执行过程：

UISearchController的使用步骤：

1、创建

//创建UISearchController
    _searchController = [[UISearchController alloc]initWithSearchResultsController:nil];

2、设置代理

    //设置代理
    _searchController.delegate = self;
    _searchController.searchResultsUpdater= self;

3、设置属性

    //设置UISearchController的显示属性，以下3个属性默认为YES
    //搜索时，背景变暗色
    _searchController.dimsBackgroundDuringPresentation = NO;
    //搜索时，背景变模糊
    _searchController.obscuresBackgroundDuringPresentation = NO;
    //隐藏导航栏
    _searchController.hidesNavigationBarDuringPresentation = NO;

4、实现代理

- (void)willPresentSearchController:(UISearchController *)searchController;
- (void)didPresentSearchController:(UISearchController *)searchController;
- (void)willDismissSearchController:(UISearchController *)searchController;
- (void)didDismissSearchController:(UISearchController *)searchController;
- (void)presentSearchController:(UISearchController *)searchController;

- (void)updateSearchResultsForSearchController:(UISearchController *)searchController;

注意点：

1、如果你希望在同一个视图中显示搜索结果，则通过[[UISearchController alloc]initWithSearchResultsController:nil]。但是这是不支持TVOS，请提供TVOS一定要指定结果控制器。

[[UISearchController alloc]initWithSearchResultsController:VC]，可以实现指定结果控制器。