Question

这有点奇怪，我似乎无法弄明白。我使用Parse后端并显示TableView来加载数据并滑动以删除它。

代码的工作原理除了一部分： [tableView deleteRowsAtIndexPaths：[NSArray arrayWithObject：indexPath] withRowAnimation：UITableViewRowAnimationFade];

如果我将该代码留在应用程序崩溃中，如果我将其注释掉它可以正常工作但没有动画。我检查了放入NSLog语句以打印出indexPath.row以确保我删除并且我有正确的总行数。但是为什么没有动画就可以完美地运行但动画会崩溃？

我收到的错误消息是：

＆＃39; NSInternalInconsistencyException＆＃39;，原因：＆＃39;无效更新：无效第0节中的行数。包含在中的行数更新后的现有部分（1）必须等于数量在更新（1）之前，该部分中包含的行加或减从该部分插入或删除的行数（插入0，删除1）加上或减去移入或移出的行数该部分（0移入，0移出）。＆＃39;

我的代码是：

- (void)viewWillAppear:(BOOL)animated {
    [super viewWillAppear:animated];
    [self retrieveOrders];
}

- (void)viewDidLoad
{
    [super viewDidLoad];
    PFUser *currentUser = [PFUser currentUser];
    if (currentUser)
    {
        NSLog(@"%@'s Orders", currentUser.username);
    }

    self.refreshControl = [[UIRefreshControl alloc] init]; // Refresher MBProgress Hud
    [self.refreshControl addTarget:self action:@selector(retrieveOrders) forControlEvents:UIControlEventValueChanged]; // Refresher MBProgress Hud
}

#pragma mark - Table view data source

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
    return 1;
}

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


- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"Cell" forIndexPath:indexPath];

    // Configure the cell...

    PFObject *order = [self.ordersArray objectAtIndex:indexPath.row];

//    NSData *imageData = [NSData dataWithContentsOfURL:blogPost.thumbnailURL];
//    UIImage *image = [UIImage imageWithData:imageData];
//    cell.imageView.image = image;

    _updatedAt = order.updatedAt;

    cell.imageView.image = [UIImage imageNamed:@"treehouse.png"];
    cell.textLabel.text = [NSString stringWithFormat:@"%@", order[@"recepientName"]];
    cell.detailTextLabel.text = [NSString stringWithFormat:@"Shipped on %@", self.formatDate];
    return cell;
}

- (void)retrieveOrders {
    PFQuery *orderQuery = [PFQuery queryWithClassName:@"Orders"];
    [orderQuery orderByAscending:@"createdAt"];

    [orderQuery findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
        if (error) {
            NSLog(@"Error %@ %@", error, [error userInfo]);
        }
        else {
            self.ordersArray = objects;
            [self.tableView reloadData];
        }
        if ([self.refreshControl isRefreshing]) {
            [self.refreshControl endRefreshing];
        }
    }];
}

-(NSString *) formatDate{
    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
    [dateFormatter setDateFormat:@"MMM dd, yyyy"];
    [dateFormatter stringFromDate:_updatedAt];
    NSString *newTime = [dateFormatter stringFromDate:[[NSDate alloc]init]];
    return newTime;
}

- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath {
    return 70;
}

- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle
forRowAtIndexPath:(NSIndexPath *)indexPath {
    // If row is deleted, remove it from the list.
    PFObject *removeObject = [self.ordersArray objectAtIndex:indexPath.row];
    NSString *deleteId = removeObject.objectId;
    PFObject *object = [PFObject objectWithoutDataWithClassName:@"Orders" objectId:deleteId];
    [object deleteInBackground];

    if (editingStyle == UITableViewCellEditingStyleDelete) {
    // Animate the deletion from the table.
       [tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationFade];
        NSLog(@"indexPath.row = %ld", (long)indexPath.row);
        [self.tableView reloadData];
    }
}

Answer 1

在致电retrieveOrders后，您永远不会致电deleteInBackground，以便self.ordersArray可能仍然保留对您“已删除”对象的引用。 deleteRowsAtIndexPaths:withRowAnimation:期望行数不同。

此外，deleteInBackground在后台运行，因此调用retrieveOrders可能甚至无法完全解决您的问题。

修改

你也可以试试这个......

- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath { if (editingStyle == UITableViewCellEditingStyleDelete) { PFObject *removeObject = [self.ordersArray objectAtIndex:indexPath.row]; NSString *deleteId = removeObject.objectId; PFObject *object = [PFObject objectWithoutDataWithClassName:@"Orders" objectId:deleteId]; [object deleteInBackgroundWithBlock:^(BOOL succeeded, NSError *error) { if (succeeded) { [tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationFade]; NSLog(@"indexPath.row = %ld", (long)indexPath.row); } }]; } }

tableView deleteRowsAtIndexPaths动画不起作用

1 个答案: