filterContentForSearchText and shouldReloadTableForSearchString not called (UITableView & UISearchBar)

问题

I'd like to implement an incremental search of words. I implemented like below, but filterContentForSearchText and shouldReloadTableForSearchString methods are not called. Why?

WordsIndexViewController.h

#import <UIKit/UIKit.h>

@interface WordsIndexViewController : UIViewController <UITableViewDataSource, UITableViewDelegate, UISearchDisplayDelegate, UISearchBarDelegate>

@end

WordsIndexViewController.m

#import "WordsIndexViewController.h"
#import "WordsShowViewController.h"
#import "Word.h"

@interface WordsIndexViewController ()

@property (strong, nonatomic) UITableView *tableView;

@property (strong, nonatomic) NSArray *words;
@property (strong, nonatomic) NSMutableArray *searchedWords;

@end

@implementation WordsIndexViewController

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        // Custom initialization
    }
    return self;
}

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view.

    _words = [[app models] objectForKey:@"words"];
    _searchedWords = [NSMutableArray arrayWithArray:@[]];

    UITableView *tableView = [[UITableView alloc] initWithFrame:CGRectMake(0, 0, 320, 480) style:UITableViewStylePlain];
    tableView.delegate = self;
    tableView.dataSource = self;
    _tableView = tableView;

    UISearchBar *searchBar = [[UISearchBar alloc] initWithFrame:CGRectMake(0, 0, self.view.bounds.size.width, 44)];
    searchBar.delegate = self; // needed?
    [searchBar sizeToFit]; // needed?

    UISearchDisplayController *searchDisplayController = [[UISearchDisplayController alloc] initWithSearchBar:searchBar contentsController:self];
    searchDisplayController.delegate = self;
    searchDisplayController.searchResultsDelegate = self;
    searchDisplayController.searchResultsDataSource = self;
    _tableView.tableHeaderView = searchBar;

    [self.view addSubview:_tableView];
}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

#pragma mark - related to UITableView
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
    NSLog(@"START numberOfRowsInSection");

    NSArray *words = nil;
    if (tableView == self.searchDisplayController.searchResultsTableView) {
        words = _searchedWords;
    } else {
        words = _words;
    }

    return [words count];
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    NSLog(@"START cellForRowAtIndexPath");

    NSArray *words = nil;
    if (tableView == self.searchDisplayController.searchResultsTableView) {
        words = _searchedWords;
    } else {
        words = _words;
    }

    UITableViewCell *cell = [[UITableViewCell alloc] init];
    Word *word = words[indexPath.row];
    cell.textLabel.text = word.spelling;
    cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;

    return cell;
}
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
    NSArray *words = nil;
    if (tableView == self.searchDisplayController.searchResultsTableView) {
        words = _searchedWords;
    } else {
        words = _words;
    }

    WordsShowViewController *controller = [[WordsShowViewController alloc] initWithNibName:@"ViewController" bundle:nil];
    controller.word = (Word *)words[indexPath.row];
    [self.navigationController pushViewController:controller animated:YES];
}

#pragma mark - related to Search Bar
- (BOOL)searchDisplayController:(UISearchDisplayController *)controller shouldReloadTableForSearchString:(NSString *)searchString {
    NSLog(@"Query: %@", searchString); // NOT CALLED...

    [self filterContentForSearchText:searchString
        scope:[
            [self.searchDisplayController.searchBar scopeButtonTitles]
            objectAtIndex:[self.searchDisplayController.searchBar selectedScopeButtonIndex]
        ]
    ];

    return YES;
}
- (void)filterContentForSearchText:(NSString*)searchString scope:(NSString*)scope {
    NSLog(@"START filterContentForSearchText"); // NOT CALLED...

    [_searchedWords removeAllObjects];

    for(Word *word in _words) {
        NSRange range = [word.spelling rangeOfString:searchString options:NSCaseInsensitiveSearch];
        if(range.length > 0) {
            [_searchedWords addObject:word];
        }
    }
}

@end

Word.h

#import <Foundation/Foundation.h>

@interface Word : NSObject

@property (strong, nonatomic) NSString *identifier;
@property (strong, nonatomic) NSString *spelling;

- (id)initWith:(NSString *)spelling;

@end

Word.m

#import "Word.h"

@implementation Word

- (id)initWith:(NSString *)spelling {
    self = [super init];
    if (!self) {
        return nil;
    }

    CFUUIDRef uuid = CFUUIDCreate(NULL);
    _identifier = (NSString *)CFBridgingRelease(CFUUIDCreateString(NULL, uuid));
    CFRelease(uuid);

    _spelling = spelling;

    return self;
}

@end

Regards,

回答1:

Finally, I solved the question myself.

To solve it, I called shouldReloadTableForSearchString in textDidChange then the incremental search worked. A diff belows:

WordsIndexViewController.m

@@ -16,6 +16,7 @@
      @property (strong, nonatomic) NSArray *words;
 @property (strong, nonatomic) NSMutableArray *searchedWords;
+@property (strong, nonatomic) UISearchDisplayController *displayController;

 @end

@@ -52,6 +53,7 @@
     searchDisplayController.searchResultsDelegate = self;
     searchDisplayController.searchResultsDataSource = self;
     _tableView.tableHeaderView = searchBar;
+    _displayController = searchDisplayController;

     [self.view addSubview:_tableView];
 }
@@ -132,5 +134,9 @@
         }
     }
 }
+- (void) searchBar:(UISearchBar *)searchBar textDidChange:(NSString *) searchText {
+    [self searchDisplayController:_displayController shouldReloadTableForSearchString:searchText];
+}

 @end

Thanks,

回答2:

Make sure you create an iVar for the UISearchDisplayController in your header file.

If you create an UISearchDisplayController using:

UISearchDisplayController* searchDisplayController = [[UISearchDisplayController alloc] initWithSearchBar:searchField contentsController:self];

it will get released by ARC, it will not call any delegate methods and when you'll call self.searchDisplayController (the UIViewController's property) it will be nil.

So, the fix is: In your header (.h) file:

@interface MenuViewController : UIViewController <UITableViewDataSource, UITableViewDelegate, UISearchBarDelegate, UISearchDisplayDelegate> {
        UISearchDisplayController* searchDisplayController;
        UISearchBar *searchField;
        UITableView* tableView;
        NSArray* searchResults;
}

and in the implementation (.m) file:

searchField = [[UISearchBar alloc] initWithFrame:CGRectMake(0, 0, self.view.frame.size.width, 49)];
searchField.delegate = self;

searchDisplayController = [[UISearchDisplayController alloc] initWithSearchBar:searchField contentsController:self];
searchDisplayController.delegate = self;
searchDisplayController.searchResultsDataSource = self;
searchDisplayController.searchResultsDelegate = self;

tableView.tableHeaderView = searchField;
tableView.contentOffset = CGPointMake(0, searchField.frame.size.height);

When implemented like that, you can call both self.searchDisplayController and searchDisplayController in the rest of your code.

来源：https://stackoverflow.com/questions/16764022/filtercontentforsearchtext-and-shouldreloadtableforsearchstring-not-called-uita