Question

i’am creating an iOS application which is similar to bbc application
– I have a table view which has two section
– 1st section contains cells containing scrollview wid images
– 2nd section contains expandable cells which contains scrollview did images
so the problem is that
when i use the dequereusable its showing weird behaviors like when the bottommost cell in the table is expanded the first cell in the first gets cleared etc etc
so i have just stopped using the queue and everything started working fine
but now when i added images after scrolling the cells which is not in the view gets refreshed and its
taking a lot of time to load

so could kindly guide me how to use the queue wisely in the code
described below
– (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath

{

NSString *CellIdentifier=@"cell";

    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];

if (cell== nil) {
        cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:@"hai"] autorelease];

///[here a different name has been used for the reuse identifier];////

      if ([self tableView:tableView inSection2:indexPath.section]) {
        Coffee *co =[appDelegate.coffeeArray2 objectAtIndex:indexPath.section-s1Count-1];
         cell.textLabel.text=co.coffeeName;

    }

    if ([self tableView:tableView inSection1:indexPath.section]) {

        Coffee *co =[appDelegate.coffeeArray1 objectAtIndex:indexPath.section];
        cell.textLabel.text = co.coffeeName;
        CGRect cellname = CGRectMake(5, 0, 290, 25);
        UILabel *cellabel = [[[UILabel alloc] initWithFrame:cellname] autorelease];

        cellabel.backgroundColor = [UIColor whiteColor];

        cellabel.font = [UIFont italicSystemFontOfSize:20];

        cellabel.textColor=[UIColor blueColor];

        cellabel.highlightedTextColor = [UIColor clearColor];

       cellabel.text=co.coffeeName;

        [cell.contentView addSubview:cellabel];


    }


// Configure the cell...

if ([self tableView:tableView canCollapseSection:indexPath.section]) 

{
    if (!indexPath.row)

    {     

        // first row

       // only top row showing



        if ([expandedSections containsIndex:indexPath.section])

        {

            cell.accessoryView = [myuicontroller accessoryWithColor:[UIColor grayColor] type:DTCustomColoredAccessoryTypeUp];

        }

        else

        {

            cell.accessoryView = [myuicontroller accessoryWithColor:[UIColor grayColor] type:DTCustomColoredAccessoryTypeDown];

        }





    }

    else

    {

        // all other rows

        cell.accessoryView = nil;    

        cell.accessoryType =UITableViewCellAccessoryDisclosureIndicator;


        CGRect cellname = CGRectMake(5, 0, 290, 25);

        UILabel *cellabel = [[[UILabel alloc] initWithFrame:cellname] autorelease];

        cellabel.backgroundColor = [UIColor whiteColor];

        cellabel.font = [UIFont italicSystemFontOfSize:13];

        cellabel.textColor=[UIColor blueColor];

        cellabel.highlightedTextColor = [UIColor clearColor];

       // cellabel.text =[NSString stringWithFormat:@"category"];

        [cell.contentView addSubview:cellabel];

        myscrollView *svb;
           svb=[[myscrollView alloc]initwitharray:appDelegate.newscat1];

}else{

    myscrollView *s;

    NSLog(@"inside the textlabel ext%@",cell.textLabel.text);

    NSLog(@"count of array  %d",[appDelegate.newscat1 count]);

    NSString *cat=cell.textLabel.text;

            [cell.contentView addSubview:s];

}

}   



return cell;

}

Answer 1

You need to set the alternative reuse identifier before you dequeue the cell. At the moment you are dequeuing a cell with identifier “cell” regardless of the section you are in, so you will often be returning a section 0 cell for a section 1 part of the table.

So, branch your code so that you do different things depending on the value of indexPath.section:

if (indexPath.section == 0)
    cellIdentifier = @"thisCell";
else
    cellIdentifier = @"otherCell";

Then dequeue your cell, if it is nil, create with the same cell identifier variable above.

You should only be adding subviews inside your (cell = nil) code – otherwise you will end up with cells with lots of overlapping subviews and will be wasting memory. If a cell has been dequeued, you just configure the existing subviews, you don’t make new ones. You can assign tags to your subviews as you add them to assist with this.