UISearchController应用

一、UISearchController在UITableView的使用
1、在放初始化的搜索框中的控制器代码。

- (void)viewDidLoad {
    [super viewDidLoad];
    [self initUI];
    [self initData];
}
/**
 初始化UI
 */
- (void)initUI{
    //必须要将这个属性设置成YES，不然会在搜索结果的界面有64px的偏移
    self.definesPresentationContext = YES;
    SearchResultController * vc = [[SearchResultController alloc] init];
    //设置搜索的控制器
    self.searchController = [[UISearchController alloc] initWithSearchResultsController:vc];
    //当呈现的时候是否隐藏导航栏
    self.searchController.hidesNavigationBarDuringPresentation = YES;
    //点击searchBar的输入框的时候是否显示灰色的背景
    self.searchController.dimsBackgroundDuringPresentation = YES;
    self.searchController.searchBar.placeholder = @"请输入关键字";
    self.searchController.searchBar.delegate = self;
    self.searchController.searchResultsUpdater = self;
    self.searchController.delegate = self;
    self.tableView.tableHeaderView = self.searchController.searchBar;
    [self.tableView registerClass:[UITableViewCell class] forCellReuseIdentifier:@"cell"];
}
/**
 初始化数据源
 */
- (void)initData{
    self.dataArray = [[NSMutableArray alloc] init];
    NSString *path = [[NSBundle mainBundle] pathForResource:@"country" ofType:@"txt"];
    NSString *countriesContent = [NSString stringWithContentsOfFile:path encoding:NSUTF8StringEncoding error:nil];
    self.dataArray = [countriesContent componentsSeparatedByString:@"\n"];
}

#pragma mark - UISearchControllerUpdate
- (void)updateSearchResultsForSearchController:(UISearchController *)searchController
{
    NSString *searchText = searchController.searchBar.text;
    NSPredicate *predicate = [NSPredicate predicateWithFormat:@"(SELF CONTAINS %@)", searchText];
    SearchResultController *resultViewCtrl = (SearchResultController *)searchController.searchResultsController;
    NSArray * arr = [_dataArray filteredArrayUsingPredicate:predicate];
    resultViewCtrl.filterArr = arr;
}

#pragma mark - UISearchController delegate method
- (void)willPresentSearchController:(UISearchController *)searchController {
    
}

- (void)didPresentSearchController:(UISearchController *)searchController {
    
}

- (void)presentSearchController:(UISearchController *)searchController {
    
}

- (void)willDismissSearchController:(UISearchController *)searchController {
    
}

- (void)didDismissSearchController:(UISearchController *)searchController {
    
}

#pragma mark - UISearchBar delegate method
- (void)searchBarTextDidBeginEditing:(UISearchBar *)searchBar {
    NSLog(@"%s", __func__);
}

- (void)searchBarCancelButtonClicked:(UISearchBar *)searchBar {
    NSLog(@"%s", __func__);
}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section{
    return self.dataArray.count;
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{
    UITableViewCell * cell = [tableView dequeueReusableCellWithIdentifier:@"cell"];
    cell.textLabel.text = self.dataArray[indexPath.row];
    return cell;
}

2、在搜索结果中的代码。

- (void)viewDidLoad {
    [super viewDidLoad];
    [self initUI];
    
    [self initData];
}
/**
 初始化UI
 */
- (void)initUI{
    [self.tableView registerClass:[UITableViewCell class] forCellReuseIdentifier:cellID];
}
/**
 初始化数据
 */
- (void)initData{
    
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section{
    return self.filterArr.count;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{
    UITableViewCell * cell = [tableView dequeueReusableCellWithIdentifier:cellID];
    cell.textLabel.text = self.filterArr[indexPath.row];
    return cell;
}
- (void)setFilterArr:(NSMutableArray *)filterArr{
    _filterArr = filterArr;
    [self.tableView reloadData];
}

二、UISearchController添加到UIScrollView上
将这个空间添加到self.view上会出现问题

    UIScrollView * scrollView = [[UIScrollView alloc] initWithFrame:CGRectMake(0, 0, self.view.eoc_width, self.view.eoc_height)];
    scrollView.backgroundColor = [UIColor redColor];
    [self.view addSubview:scrollView];
    [scrollView addSubview:self.searchCtrl.searchBar];

- (UISearchController *)searchCtrl {
    if (!_searchCtrl) {
        EOCSearchResultViewCtrl *resultSearchCtrl = [[EOCSearchResultViewCtrl alloc] init];
        _searchCtrl = [[UISearchController alloc] initWithSearchResultsController:resultSearchCtrl];
        _searchCtrl.dimsBackgroundDuringPresentation = YES;
        _searchCtrl.hidesNavigationBarDuringPresentation = YES;
        _searchCtrl.searchBar.placeholder = @"搜索";
        _searchCtrl.searchBar.delegate = self;
        _searchCtrl.searchResultsUpdater = self;
        _searchCtrl.delegate = self;
    }
    
    return _searchCtrl;
    
}

三、将UISearchController添加写成成员变量，代理方法不能不执行。原因：提前释放掉这个对象了。

    self.view.backgroundColor = [UIColor whiteColor];
    EOCSearchResultViewCtrl * vc = [[EOCSearchResultViewCtrl alloc] init];
    
    UISearchController * searchVC = [[UISearchController alloc] initWithSearchResultsController:vc];
    searchVC.searchBar.placeholder = @"搜索";
    searchVC.dimsBackgroundDuringPresentation = YES;
    searchVC.hidesNavigationBarDuringPresentation = YES;
    searchVC.searchBar.placeholder = @"八点钟学院";
    searchVC.searchBar.delegate = self;
    searchVC.searchResultsUpdater = self;

四、改变UISearchController中searchBar的外观

    //修改searchBar中的背景色
    self.searchCtrl.searchBar.barTintColor = [UIColor grayColor];
    //修改searchBar的光标和cancel的颜色
    self.searchCtrl.searchBar.tintColor = [UIColor orangeColor];
    //改变searchBar中的搜索图标
    [self.searchCtrl.searchBar setImage:[UIImage imageNamed:@"voice_gray"] forSearchBarIcon:UISearchBarIconSearch state:UIControlStateNormal];
    //改变searchBar中清楚按钮的图标
    [self.searchCtrl.searchBar setImage:[UIImage imageNamed:@"message_gray"] forSearchBarIcon:UISearchBarIconClear state:UIControlStateNormal];
    //改变searchBar中清楚按钮高亮状态中的图标
    [self.searchCtrl.searchBar setImage:[UIImage imageNamed:@"message_gray"] forSearchBarIcon:UISearchBarIconClear state:UIControlStateHighlighted];
    //改变输入框的背景色和文字颜色
    for (UIView *subView in self.searchVC.searchBar.subviews){
        for (UIView *secondLevelSubview in subView.subviews){
            if ([secondLevelSubview isKindOfClass:[UITextField class]]){
                UITextField *searchBarTextField = (UITextField *)secondLevelSubview;
                searchBarTextField.backgroundColor = [UIColor colorWithHex:0x8C8F93 alpha:1];
                UIColor * color = [UIColor colorWithHex:0x607AA8 alpha:1];
                searchBarTextField.attributedText = [[NSAttributedString alloc] initWithString:@"搜索" attributes:@{NSForegroundColorAttributeName:color}];
                break;
            }
        }
    }
    [self.searchVC.searchBar setImage:[UIImage imageNamed:@"dev_search-1"] forSearchBarIcon:UISearchBarIconSearch state:UIControlStateNormal];
    //一下代码为修改placeholder字体的颜色和大小
    UITextField * searchField = [self.searchVC.searchBar valueForKey:@"_searchField"];
    [searchField setValue:[UIColor redColor] forKeyPath:@"_placeholderLabel.textColor"];
     [searchField setValue:[UIFont boldSystemFontOfSize:16] forKeyPath:@"_placeholderLabel.font"];

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