UITableViewCell Expandable Crash

Question

I am facing a problem about expandable tableviewcell. It crashes when i try to expand tableviewcell. I don't understand where app crashes. Please suggest me some solution. Please Help Me.

My Code:

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
   if (appDelegate.array_proj == (id)[NSNull null])
        return 0;
    else
        return [appDelegate.array_proj count];
}

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

    if ([expandedSections containsIndex:section])
    {
        if ([appDelegate.array_task count]==0)
        {
            return 0;
        }
        else
        {
            NSLog(@"array task count: %d",[appDelegate.array_task count]);
            return [appDelegate.array_task count];
        }
    }
    return 1;
}

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

    if (cell ==nil){
        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
    }

    cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
    cell.selectionStyle = UITableViewCellSelectionStyleNone;
    cell.backgroundColor = [UIColor clearColor];
    cell.textLabel.textColor = [UIColor colorWithRed:53.0/255 green:53.0/255 blue:53.0/255 alpha:1.0];

    UIImageView *backgroundView = [[UIImageView alloc] initWithFrame:CGRectZero];
    cell.backgroundView = backgroundView;
    backgroundView.image = [UIImage imageNamed:@"prjctcell_bg.png"];

    if (!indexPath.row)
    {
        objePro = [appDelegate.array_proj objectAtIndex:indexPath.section];

        cell.textLabel.text = objePro.projctname;
        appDelegate.intForPid=objePro.pojctid;

        if ([expandedSections containsIndex:indexPath.section])
        {
            cell.accessoryView = [DTCustomColoredAccessory accessoryWithColor:[UIColor blackColor] type:DTCustomColoredAccessoryTypeUp];
        }
        else
        {
            cell.accessoryView = [DTCustomColoredAccessory accessoryWithColor:[UIColor blackColor] type:DTCustomColoredAccessoryTypeDown];
        }
    }
    else
    {
        if (appDelegate.array_task != (id)[NSNull null])
        {
            objePro = [appDelegate.array_proj objectAtIndex:appDelegate.storeAppDelegateIndex];
            objeTask = [appDelegate.array_task objectAtIndex:indexPath.section];

            cell.textLabel.text = objeTask.taskname;
            cell.backgroundView = nil;
            cell.accessoryView = nil;
            cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;
        }
    }
    return cell;
}

- (BOOL)tableView:(UITableView *)tableView canCollapseSection:(NSInteger)section
{
    return YES;
}

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{    
    objePro = [appDelegate.array_proj objectAtIndex:indexPath.section];
    appDelegate.intForPid=objePro.pojctid;

   [appDelegate selectTask:appDelegate.intForPid];

    if (!indexPath.row)
    {
        [tblView beginUpdates];

        //only first row toggles expand/collapse
        [tblView deselectRowAtIndexPath:indexPath animated:YES];

        NSInteger sections = indexPath.section;
        BOOL currentlyExpanded = [expandedSections containsIndex:sections];
        NSInteger rows;

        NSMutableArray *tmpArray = [NSMutableArray array];
        if (currentlyExpanded)
        {
            rows = [self tableView:tblView numberOfRowsInSection:sections];
            [expandedSections removeIndex:sections];
        }
        else
        {
            [expandedSections addIndex:sections];
            rows = [self tableView:tblView numberOfRowsInSection:sections];
        }
        for (int i=1; i<rows; i++)
        {
            NSIndexPath *tmpIndexPath = [NSIndexPath indexPathForRow:i inSection:sections];
            [tmpArray addObject:tmpIndexPath];
        }
        UITableViewCell *cell = [tblView cellForRowAtIndexPath:indexPath];

        if (currentlyExpanded)
        {

            [tblView deleteRowsAtIndexPaths:tmpArray withRowAnimation:UITableViewRowAnimationTop];
            cell.accessoryView = [DTCustomColoredAccessory accessoryWithColor:[UIColor blackColor] type:DTCustomColoredAccessoryTypeDown];
        }
        else
        {
            [tblView insertRowsAtIndexPaths:tmpArray withRowAnimation:UITableViewRowAnimationTop];
            cell.accessoryView =  [DTCustomColoredAccessory accessoryWithColor:[UIColor blackColor] type:DTCustomColoredAccessoryTypeUp];
        }
        [tblView endUpdates];
    }
}

It gives error: Assertion failure in -[UITableView _endCellAnimationsWithContext:], /SourceCache/UIKit_Sim/UIKit-2380.17/UITableView.m:1070 2013-03-20 19:14:00.102 Daily Achiever[2886:c07] * Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Invalid update: invalid number of rows in section 1. The number of rows contained in an existing section after the update (3) must be equal to the number of rows contained in that section before the update (1), plus or minus the number of rows inserted or deleted from that section (0 inserted, 0 deleted) and plus or minus the number of rows moved into or out of that section (0 moved in, 0 moved out).'

Jsdodgers Jsdodgers · Accepted Answer · 2013-03-20T13:57:24

Your problem is in these lines of code:

 [tblView deleteRowsAtIndexPaths:tmpArray withRowAnimation:UITableViewRowAnimationTop];

and

 [tblView insertRowsAtIndexPaths:tmpArray withRowAnimation:UITableViewRowAnimationTop];

The crash that you posted was due to the first one. In these lines, you are trying to insert/delete rows from the table, but your - (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section method does not change correspondingly.

It looks like you want to add/remove items from your appDelegate.array_task array whenever you are adding/removing cells from the table (as this is the array from which you are determining the row count).

As a side note, the line:

 if ([appDelegate.array_task count]==0) { 
    return 0;
 }

is not doing anything, because you have else return [appDelegate.array_task count] which means that 0 will be returned if [appDelegate.array_task count]==0 anyway.

UITableViewCell Expandable Crash

2 Answers