Question

I have looked through almost all search results, but my error doesnt go away. I have a table view initialised with 2 sections and 1 row each (from an array). I have a button for the section header view. On clicking a button I want to add a row to the 1st section. Here’s the code:

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
    return 2;
}

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

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{   
    UITableViewCell *cell = (UITableViewCell*)[self.myTableView dequeueReusableCellWithIdentifier:@"DetailCell"];
    cell.textLabel.text=[arr objectAtIndex:indexPath.row];
    cell.backgroundColor=[UIColor clearColor];
    return cell; 
} 

-(UIView*)tableView:(UITableView *)tableView viewForHeaderInSection:(NSInteger)section
{
    switch (section) {
        case 0:
            btnReleases=[UIButton buttonWithType:UIButtonTypeCustom];
            [btnReleases setFrame:CGRectMake(10, 0, 30, 39)];
            [btnReleases setImage:[UIImage imageNamed:@"buttonr.png"] forState:UIControlStateNormal];
            [btnReleases addTarget:self action:@selector(loadReleases) forControlEvents:UIControlEventTouchUpInside];
            return btnReleases;
            break;
        case 1:
            btnLinks=[UIButton buttonWithType:UIButtonTypeCustom];
            [btnLinks setFrame:CGRectMake(10, 0, 30, 39)];
            [btnLinks setImage:[UIImage imageNamed:@"buttonl.png"] forState:UIControlStateNormal];
            [btnLinks addTarget:self action:nil forControlEvents:UIControlEventTouchUpInside];
            return btnLinks;
            break;
        default:
            break;
    }

}
-(void)loadReleases
{

    [self.myTableView beginUpdates];
        [arr addObject:@"WTF"];
    NSArray *insert0 = [NSArray arrayWithObject:[NSIndexPath indexPathForRow:0 inSection:0]]; NSLog(@"%@",insert0);
    [self.myTableView insertRowsAtIndexPaths:insert0 withRowAnimation:UITableViewRowAnimationBottom];
    [self.myTableView endUpdates];
}

Heres the error:

* Assertion failure in -[UITableView _endCellAnimationsWithContext:], /SourceCache/UIKit_Sim/UIKit-1912.3/UITableView.m:1046

Answer 1

Since you’re using [arr count] as the return value for tableView:numberOfRowsInSection:, at the end of the beginUpdates…endUpdates block the tableView is expecting that there will be two rows in each of your tableView sections, but your call to insertRowsAtIndexPaths: only indicates that a row is being to section 0.

You need to fix your tableView:numberOfRowsInSection: to return different values depending on the section:

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    if (section == 0) {
        return [arr count];
    } else {
        return 1;
    }
}

Note that there’s a lot of fishy stuff going on with your tableView: you have two sections, but you’re showing the same exact row 0 in each section. And the insertion behavior within your sections is pretty wonky: you start off showing just one row, corresponding to case 0 in your switch, then you indicate that you’re inserting a row at row 0, after which you’ll be showing the case 0 row at row 0 and the case 1 row at row 1. So you should really be inserting a row at row 1 instead of row 0:

NSArray *insert0 = [NSArray arrayWithObject:[NSIndexPath indexPathForRow:1 inSection:0]]; 
[self.myTableView insertRowsAtIndexPaths:insert0 withRowAnimation:UITableViewRowAnimationBottom];