Tableview使用空数组获取索引超出范围

Posted 2023-02-27

【中文标题】Tableview使用空数组获取索引超出范围

【英文标题】：Tableview get index out of bounds with empty array

【发布时间】：2013-04-10 05:09:42

【问题描述】：

我有一个tableview，里面有一个fetchedresultscontroller 和一个searchbar。到目前为止，在创建应用程序时，我只使用了 7 个单元格并且工作得很好，但是自从我开始使用超过 7 个单元格后，当我触摸搜索栏时，我得到了超出范围空数组的错误。但是当我把它放回 7 个单元格时，它工作得很好。

可能出了什么问题？

错误： 由于未捕获的异常“NSRangeException”而终止应用程序，原因：“*-[__NSArrayM objectAtIndex:]: 索引 2 超出空数组的范围”

- (void)viewDidLoad

    [super viewDidLoad];

    self.title = @"Exercises";



    id appDelegate = [[UIApplication sharedApplication] delegate];
    _managedObjectContext = [appDelegate managedObjectContext];

    NSError *error;
    if (![[self fetchedResultsController] performFetch:&error]) 
        NSLog(@"%@ %@", error, [error userInfo]);
        abort();
    

    _searchResults = [[NSMutableArray alloc] init];




- (void)viewDidAppear:(BOOL)animated

    [super viewDidAppear:animated];

    NSIndexPath *selectedIndexPath = [_tableView indexPathForSelectedRow];
    if (!selectedIndexPath) 
        [_tableView setContentOffset:CGPointMake(0, 44) animated:NO];
    
    else 
        [_tableView deselectRowAtIndexPath:selectedIndexPath animated:YES];
    


- (void)viewDidDisappear:(BOOL)animated

    [super viewDidDisappear:animated];
    if (self.searchDisplayController.isActive) 
        [self.searchDisplayController setActive:NO animated:YES];
    


- (void)didReceiveMemoryWarning

    [super didReceiveMemoryWarning];


#pragma mark - UITableViewDataSource

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView

    if (self.searchDisplayController.isActive) 
        return 1;
    
    return [[_fetchedResultsController sections] count];


- (NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section

    if (self.searchDisplayController.isActive) 
        return nil;
    
    return [[[_fetchedResultsController sections] objectAtIndex:section] name];


- (UIView *)tableView:(UITableView *)tableView viewForHeaderInSection:(NSInteger)section

    UIView *view = [[UIView alloc] initWithFrame:CGRectMake(0, 0, self.view.bounds.size.width, 22)];
    view.backgroundColor = [UIColor colorWithRed:20.0/255.0 green:20.0/255.0 blue:20.0/255.0 alpha:0.8];

    UILabel *sectionLabel = [[UILabel alloc] initWithFrame:CGRectMake(20, 0, 160, 22)];
    sectionLabel.font = [UIFont fontWithName:@"Avenir-Book" size:16.0f];
    sectionLabel.text = @"Search Results";

    if (!self.searchDisplayController.isActive) 
        sectionLabel.text = [[[_fetchedResultsController sections] objectAtIndex:section] name];
    

    sectionLabel.backgroundColor = [UIColor clearColor];
    sectionLabel.textColor = [UIColor whiteColor];
    [view addSubview:sectionLabel];
    return view;


- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section

    if (self.searchDisplayController.isActive) 
        return [_searchResults count];
    
    return [[[_fetchedResultsController sections] objectAtIndex:section] numberOfObjects];


- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath

    static NSString *cellIdentifier = @"exerciseCell";
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:cellIdentifier];

    if (!cell) 
        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:cellIdentifier];
        [self stampCell:cell atIndexPath:indexPath];
    

    [self configureCell:cell atIndexPath:indexPath];

    return cell;



#pragma mark - Cell

- (void)stampCell:(UITableViewCell *)cell atIndexPath:(NSIndexPath *)indexPath

    if ([cell.reuseIdentifier isEqualToString:@"exerciseCell"]) 

        UILabel *textLabel = [[UILabel alloc] initWithFrame:CGRectMake(70, 2, 150, 22)];
        textLabel.tag = kExerciseCellTextLabel;
        textLabel.font = [UIFont systemFontOfSize:18.0];
        textLabel.textColor = [UIColor blackColor];
        textLabel.highlightedTextColor = [UIColor whiteColor];
        textLabel.backgroundColor = [UIColor clearColor];
        [cell.contentView addSubview:textLabel];

        UILabel *detailTextLabel = [[UILabel alloc] initWithFrame:CGRectMake(70, 24, 150, 18)];
        detailTextLabel.tag = kExerciseCellDetailTextLabel;
        detailTextLabel.font = [UIFont systemFontOfSize:14.0];
        detailTextLabel.textColor = [UIColor colorWithRed:128.0/255.0 green:128.0/255.0 blue:128.0/255.0 alpha:1.0];
        detailTextLabel.highlightedTextColor = [UIColor colorWithRed:127.0/255.0 green:127.0/255.0 blue:127.0/255.0 alpha:1.0];
        detailTextLabel.backgroundColor = [UIColor clearColor];
        [cell.contentView addSubview:detailTextLabel];

    


- (void)configureCell:(UITableViewCell *)cell atIndexPath:(NSIndexPath *)indexPath

    if ([cell.reuseIdentifier isEqualToString:@"exerciseCell"]) 

        UILabel *textLabel = (UILabel *)[cell.contentView viewWithTag:kExerciseCellTextLabel];
        UILabel *detailTextLabel = (UILabel *)[cell.contentView viewWithTag:kExerciseCellDetailTextLabel];

        Exercise *exercise;

        if (self.searchDisplayController.isActive) 
            exercise = [_searchResults objectAtIndex:indexPath.row];
        
        else 
            exercise = [_fetchedResultsController objectAtIndexPath:indexPath];
        

        textLabel.text = [exercise valueForKey:kExerciseName];
        detailTextLabel.text = [NSString stringWithFormat:@"%@ - %@", [[exercise valueForKey:kExerciseEType] valueForKey:kExerciseTypeName], [[exercise valueForKey:kExerciseGear] valueForKey:kGearName]];

        cell.selectionStyle = UITableViewCellSelectionStyleGray;
        cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;

    



#pragma mark - UITableViewDelegate

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath

    [self performSegueWithIdentifier:@"exerciseDetail" sender:self];


#pragma mark - UISearchBarDelegate

- (BOOL)searchDisplayController:(UISearchDisplayController *)controller shouldReloadTableForSearchString:(NSString *)searchString

    [_searchResults removeAllObjects];
    if (searchString.length > 0) 

        for (Exercise *exercise in [_fetchedResultsController fetchedObjects]) 
            NSRange range = [[exercise valueForKey:kExerciseName] rangeOfString:searchString options:NSCaseInsensitiveSearch];
            if (range.location == 0) 
                [_searchResults addObject:exercise];
            
        
    
    return YES;


- (BOOL)searchBarShouldBeginEditing:(UISearchBar*)searchBar 
    [super setPan];
    return YES;


- (BOOL)searchBarShouldEndEditing:(UISearchBar *)searchBar

    [super setPan];
    return YES;


#pragma mark - NSFetchedResultsControllerDelegate

- (NSFetchedResultsController *)fetchedResultsController

    if (_fetchedResultsController) 
        return _fetchedResultsController;
    

    NSFetchRequest *request = [[NSFetchRequest alloc] init];
    NSEntityDescription *entity = [NSEntityDescription entityForName:kExercise inManagedObjectContext:_managedObjectContext];
    [request setEntity:entity];

    NSSortDescriptor *sort = [NSSortDescriptor sortDescriptorWithKey:kExerciseName ascending:YES];
    [request setSortDescriptors:[NSArray arrayWithObject:sort]];

    NSFetchedResultsController *fetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:request managedObjectContext:_managedObjectContext sectionNameKeyPath:kExerciseFirstLetter cacheName:@"ExerciseList"];
    [self setFetchedResultsController:fetchedResultsController];
    [_fetchedResultsController setDelegate:self];

    return _fetchedResultsController;


- (void)controllerWillChangeContent:(NSFetchedResultsController *)controller

    [self.tableView beginUpdates];


- (void)controller:(NSFetchedResultsController *)controller didChangeSection:(id <NSFetchedResultsSectionInfo>)sectionInfo
           atIndex:(NSUInteger)sectionIndex forChangeType:(NSFetchedResultsChangeType)type

    switch(type) 
        case NSFetchedResultsChangeInsert:
            [self.tableView insertSections:[NSIndexSet indexSetWithIndex:sectionIndex] withRowAnimation:UITableViewRowAnimationFade];
            break;

        case NSFetchedResultsChangeDelete:
            [self.tableView deleteSections:[NSIndexSet indexSetWithIndex:sectionIndex] withRowAnimation:UITableViewRowAnimationFade];
            break;
    


- (void)controller:(NSFetchedResultsController *)controller didChangeObject:(id)anObject
       atIndexPath:(NSIndexPath *)indexPath forChangeType:(NSFetchedResultsChangeType)type
      newIndexPath:(NSIndexPath *)newIndexPath

    UITableView *tableView = self.tableView;

    switch(type) 
        case NSFetchedResultsChangeInsert:
            [tableView insertRowsAtIndexPaths:@[newIndexPath] withRowAnimation:UITableViewRowAnimationFade];
            break;

        case NSFetchedResultsChangeDelete:
            [tableView deleteRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationFade];
            break;

        case NSFetchedResultsChangeUpdate:
            [self configureCell:[tableView cellForRowAtIndexPath:indexPath] atIndexPath:indexPath];
            break;

        case NSFetchedResultsChangeMove:
            [tableView deleteRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationFade];
            [tableView insertRowsAtIndexPaths:@[newIndexPath] withRowAnimation:UITableViewRowAnimationFade];
            break;
    


- (void)controllerDidChangeContent:(NSFetchedResultsController *)controller

    [self.tableView endUpdates];


@end

【问题讨论】：

我编辑了它，并添加了触摸搜索栏时触发的错误。

【参考方案1】：

它显示一些数组仍然是空的..检查它的更好方法

-将 NSLog 语句放在数组元素之后并运行它。它会显示哪个数组仍然为空。

这样做如果您的问题没有得到解决..请告诉我..这样，我可以进一步帮助您..

【讨论】：

你检查这个链接..它可能对你有帮助..***.com/questions/4965827/…

哪里是放置 nslog 的有效位置？或者位置无关紧要。

在视图 didload 中对所有获取的对象进行了快速枚举，以检查数组中是否有任何对象为 nil，但没有一个为 nil。你是这个意思吗？

@JakeOrtiz k..让我再检查一次..您还将 NSLog 放在获取行详细信息的位置..

放在configurecell方法中可以吗？

【参考方案2】：

您在哪里看到崩溃 - 仅显示搜索结果或显示整个列表时？

如果只是搜索结果，那么您的 _searchResults 记录不超过 7 条。

如果是显示所有结果时，请检查 _fetchedResultsController.sections 的每个值中的记录数。看起来他们的记录不超过 7 条。

【讨论】：

如果我有 8 个或更多单元格并触摸它崩溃的搜索栏，它甚至不会显示 searchdisplaycontroller。而且它不需要对searchResults做任何事情，当搜索栏被触摸时它甚至不调用uitableviewdatasource。

【参考方案3】：

您好，我想您从 _searchResults 中删除所有元素可能是因为此应用程序崩溃了。请检查一次。

- (BOOL)searchDisplayController:(UISearchDisplayController *)controller shouldReloadTableForSearchString:(NSString *)searchString

    [_searchResults removeAllObjects];

【讨论】：

我应该删除那行吗？