UISearchResultsController 在设备上崩溃（索引超出空数组的范围）

Question

我正在使用 UISearchResultsController 过滤来自 fetchedResultsController 的数据。以下是相关代码：

在 RootVieweController.h 中：

@interface RootViewController : UITableViewController <NSFetchedResultsControllerDelegate, AdditionViewControllerDelegate, UISearchBarDelegate, UISearchDisplayDelegate> {

    NSArray *filteredListContent;   
    NSString *savedSearchTerm;
    NSInteger savedScopeButtonIndex;
    BOOL searchIsActive;
}
@property (nonatomic, retain) NSArray *filteredListContent;
@property (nonatomic, copy) NSString *savedSearchTerm;
@property (nonatomic) NSInteger savedScopeButtonIndex;
@property (nonatomic) BOOL searchIsActive;

在 RootViewController.m 中：

-(void)viewDidLoad {
    [snip]
    UISearchBar *searchBar = [[UISearchBar alloc] initWithFrame:CGRectMake(0, 0, 300, 40)];
    searchBar.delegate = self;
    searchBar.scopeButtonTitles = [NSArray arrayWithObjects:@"Scope 1", @"Scope 2", nil];
    [searchBar sizeToFit];
    searchBar.autocorrectionType = UITextAutocorrectionTypeNo;
    self.tableView.tableHeaderView = searchBar;
    [searchBar release];
    [self.tableView setContentOffset:CGPointMake(0, 40)];

    UISearchDisplayController *searchDisplayController = [[UISearchDisplayController alloc] initWithSearchBar:searchBar contentsController:self];
    [self performSelector:@selector(setSearchDisplayController:) withObject:searchDisplayController];

    [searchDisplayController setDelegate:self];
    [searchDisplayController setSearchResultsDataSource:self];
    [searchDisplayController setSearchResultsDelegate:self];
    [searchDisplayController release];

    self.filteredListContent = [NSMutableArray arrayWithCapacity:[[[self fetchedResultsController] fetchedObjects] count]];

    if (self.savedSearchTerm) {
        [self.searchDisplayController setActive:self.searchIsActive];
        [self.searchDisplayController.searchBar setSelectedScopeButtonIndex:self.savedScopeButtonIndex];
        [self.searchDisplayController.searchBar setText:savedSearchTerm];
    
        self.savedSearchTerm = nil;
    }
}

- (NSInteger)tableView:(UITableView *)theTableView numberOfRowsInSection:(NSInteger)section {
    // Return the number of rows in the section.
    if (theTableView == self.searchDisplayController.searchResultsTableView) {
        NSLog(@"Search Cells: %i", [self.filteredListContent count]);
        return [self.filteredListContent count];
    }
    id <NSFetchedResultsSectionInfo> sectionInfo = [[fetchedResultsController sections] objectAtIndex:section];
    NSLog(@"Normal cells: %i", [sectionInfo numberOfObjects]);
    return [sectionInfo numberOfObjects];
}

-(void)configureCell:(CustomTableViewCell *)cell atIndexPath:(NSIndexPath *)indexPath
{
    //Called from cellForRowAtIndexPath

    Object *object = nil;
    if (self.searchIsActive) {
        object = [[self filteredListContent] objectAtIndex:[indexPath row]];
    } else {
        object = [fetchedResultsController objectAtIndexPath:indexPath];
    }

    [snip]
}


#pragma mark -
#pragma mark Search functions

-(void)filterContentForSearchText:(NSString *)searchText scope:(NSString *)scope {
    if ([scope isEqualToString:@"Scope 1"]) {
        NSPredicate *predicate = [NSPredicate predicateWithFormat:@"scope1 BEGINSWITH[cd] %@", searchText];
        self.filteredListContent = [[[self fetchedResultsController] fetchedObjects] filteredArrayUsingPredicate:predicate];
    } else {
        NSPredicate *predicate = [NSPredicate predicateWithFormat:@"scope2 BEGINSWITH[cd] %@", searchText];
        self.filteredListContent = [[[self fetchedResultsController]fetchedObjects] filteredArrayUsingPredicate:predicate];
    }
}

#pragma mark -
#pragma mark UISearchDisplayController Delegate Methods

- (void)searchDisplayController:(UISearchDisplayController *)controller willShowSearchResultsTableView:(UITableView *)theTableView {
    NSLog(@"Showing search results");
}

-(BOOL)searchDisplayController:(UISearchDisplayController *)controller shouldReloadTableForSearchString:(NSString *)searchString {
    [self filterContentForSearchText:searchString scope:
     [[self.searchDisplayController.searchBar scopeButtonTitles] objectAtIndex:
      [self.searchDisplayController.searchBar selectedScopeButtonIndex]]];

    NSLog(@"Reloading for string");

    return YES;
}

-(BOOL)searchDisplayController:(UISearchDisplayController *)controller shouldReloadTableForSearchScope:(NSInteger)searchOption {
    [self filterContentForSearchText:[self.searchDisplayController.searchBar text] scope:
     [[self.searchDisplayController.searchBar scopeButtonTitles] objectAtIndex:searchOption]];

    NSLog(@"Reloading for scope");

    return YES;
}

-(void)searchDisplayControllerWillBeginSearch:(UISearchDisplayController *)controller {
    self.searchDisplayController.searchResultsTableView.rowHeight = 55;
    self.searchIsActive = YES;
}

-(void)searchDisplayControllerDidEndSearch:(UISearchDisplayController *)controller {
    self.searchIsActive = NO;
}

这在模拟器中效果很好。但在设备上，当尝试显示 searchResultsTableView 时，它会在 configureCell 中的 object = [[selffilteredListContent] objectAtIndex:[indexPath row]]; 上崩溃。我收到错误 [NSMutableArray objectAtIndex:]: index 7超出空数组范围。始终索引 7。我在这里缺少什么？

--更新--

修复：翻转 searchIsActive BOOL 以打开 searchDisplayControllerDidBeginSearch 而不是 searchDisplayControllerWillBeginSearch 和 searchDisplayControllerWillEndSearch 而不是 searchDisplayControllerDidEndSearch。这可以防止表尝试配置不存在的单元格。不知道为什么模拟器没有捕捉到这个

Answer 1

如果它引用的数组为空，那么当您尝试从空数组填充表视图时，它的索引是什么并不重要。

您的 NSMutableArray filteredListContent 是否已填充（即您是否从获取的结果控制器返回搜索结果）？您检查过 filterContentForSearchText: 中数组的内容吗？

PS 我喜欢你的风格... BeerListTableViewCell :)

Answer 2

我在更新现有应用程序时遇到了完全相同的崩溃。该代码几乎与原始海报完全相同，我的应用程序中唯一更改的是数据库。 没有代码更改。

对于旧数据库，当搜索显示控制器开始搜索时，不会调用表视图数据源方法。

对于新数据库，当搜索显示控制器开始搜索时，表视图数据源方法确实会被调用。

相同的核心数据实体、相同的数据库结构、相同的代码、相同的 nib。在模拟器或设备上出现同样的问题。