iOS開發實戰之搜索控制器UISearchController使用

當tableView中的數據過多的時候，在tableView上加一個搜索框就變的很必要了，本文就討論搜索控制器的使用，以及謂詞的簡單實現。

.m文件中代碼如下 
添加搜索控制器的各種協議

<UISearchBarDelegate,UISearchResultsUpdating,UIAlertViewDelegate>

創建兩個實例和數據源

{
 NSArray * _dataSource;
}
@property(nonatomic,strong)UISearchController *searchController;//搜索控制器
@property (strong, nonatomic)NSMutableArray  *searchList;//滿足搜索條件的數組

初始化搜索控制器的各種屬性

-(void)initMysearchBarcontroller
{
    _searchController=[[UISearchController  alloc]initWithSearchResultsController:nil];
    //設置背景不透明
    _searchController.searchBar.translucent=NO;
    _searchController.searchBar.barTintColor=[UIColor brownColor];

    //設置searchbar的邊框顏色和背景顏色一致
    _searchController.searchBar.layer.borderWidth=1;
    _searchController.searchBar.layer.borderColor=[[UIColor brownColor] CGColor];
    _searchController.searchBar.placeholder=@"搜索聯系人";
    _searchController.searchResultsUpdater = self;
    _searchController.dimsBackgroundDuringPresentation = NO;
    _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);
    _searchController.searchBar.delegate=self;
    self.tableView.tableHeaderView = self.searchController.searchBar;
    //清空tableview多余的空格線
    [self.tableView setTableFooterView:[[UIView alloc]initWithFrame:CGRectZero]];

}

在輸入搜索框中輸入文本執行的代理函數

//每輸入一個字符都會執行一次
-(void)updateSearchResultsForSearchController:(UISearchController *)searchController {
    NSString *searchString = [self.searchController.searchBar text];
    //謂詞搜索
    NSPredicate *preicate = [NSPredicate predicateWithFormat:@"SELF.name CONTAINS[c] %@", searchString];

    if (self.searchList!= nil) {
        [self.searchList removeAllObjects];
    }

    //過濾數據
    self.searchList= [NSMutableArray arrayWithArray:[_dataSource filteredArrayUsingPredicate:preicate]];
    //刷新表格

    [self.tableView reloadData];

}

在這個時候 就可以獲得符合你的搜索條件的數值了。 
如果你想改變tableView的顯示內容，記得reloadData。

NSPredicate *preicate = [NSPredicate predicateWithFormat:@"SELF.name CONTAINS[c] %@", searchString];

這里的SELF.name就是你數據源里的model的屬性。SELF就是model的類，這里是按照名字搜索。

獲取到篩選數組后，就要改你的tableView上顯示的東西了。 
例如：

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
//控制器使用的時候，就是點擊了搜索框的時候
    if (self.searchController.active) {
        return self.searchList.count;
    }
//控制器未使用的時候
    return _dataSource.count;
}

還有其他tableView的代理函數也要改。

全部寫完后，會發現點了搜索框之后右邊有個取消的英文。怎么變中文呢，如下

-(BOOL)searchBarShouldBeginEditing:(UISearchBar *)searchBar
{
    [searchBar setShowsCancelButton:YES animated:YES];
    for (id obj in [searchBar subviews]) {
        if ([obj isKindOfClass:[UIView class]]) {
            for (id obj2 in [obj subviews]) {
                if ([obj2 isKindOfClass:[UIButton class]]) {
                    UIButton *btn = (UIButton *)obj2;
                    [btn setTitle:@"取消" forState:UIControlStateNormal];
                }
            }
        }
    }
    return YES;
}

怎么截取那個取消按鈕的代理呢，給你官方的。

- (BOOL)searchBarShouldBeginEditing:(UISearchBar *)searchBar;                      // return NO to not become first responder
- (void)searchBarTextDidBeginEditing:(UISearchBar *)searchBar;                     // called when text starts editing
- (BOOL)searchBarShouldEndEditing:(UISearchBar *)searchBar;                        // return NO to not resign first responder
- (void)searchBarTextDidEndEditing:(UISearchBar *)searchBar;                       // called when text ends editing
- (void)searchBar:(UISearchBar *)searchBar textDidChange:(NSString *)searchText;   // called when text changes (including clear)
- (BOOL)searchBar:(UISearchBar *)searchBar shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text NS_AVAILABLE_IOS(3_0); // called before text changes

- (void)searchBarSearchButtonClicked:(UISearchBar *)searchBar;                     // called when keyboard search button pressed
- (void)searchBarBookmarkButtonClicked:(UISearchBar *)searchBar __TVOS_PROHIBITED; // called when bookmark button pressed
- (void)searchBarCancelButtonClicked:(UISearchBar *)searchBar __TVOS_PROHIBITED;   // called when cancel button pressed
- (void)searchBarResultsListButtonClicked:(UISearchBar *)searchBar NS_AVAILABLE_IOS(3_2) __TVOS_PROHIBITED; // called when search results button pressed

- (void)searchBar:(UISearchBar *)searchBar selectedScopeButtonIndexDidChange:(NSInteger)selectedScope NS_AVAILABLE_IOS(3_0);

原文鏈接：https://blog.csdn.net/clmd_ld/article/details/50782510/