UITableView is loading every cell

Question

Hey everyone,

UITableview should only load cells that is visible at first right? My tableview is loading every cell initially which slows it down a lot. I'm using around 1000 rows. Only want it to load a cell when it has to (like user scrolling down). Anyone have any ideas why it's doing this?

Answer 1

Can you please post some code? The method -tableView:cellForRowAtIndexPath is only called when a new "slot" for a potential cell opens up, so you'd need to be doing something majorly wrong to be "loading every cell" initially!

Do you perhaps mean that you're loading all the data initially, and wish to do that in batches?

Answer 2

That's right - it should only load the ones it has to. What is your UITableView's rowHeight? If that was extremely low, the Table might expect to have to load all the cells

If that's not the problem, can you paste in your tableView:cellForRowAtIndexPath: code?

Answer 3

I know cellForRowAtIndexPath is getting called initially for every cell. The height of the cells is 89.

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

static NSString *CellIdentifier = @"Cell";
UILabel *textName    = nil;
UIImageView* image    = nil;
unsigned int  DATA_TAG = 1001;
unsigned int  IMG_TAG  = 1002;

// Retrieve a cell is Available
cell = [aTableView dequeueReusableCellWithIdentifier:CellIdentifier];

// Check if no new cell was available
if (cell == nil) 
{
 cell = [[[UITableViewCell alloc] initWithFrame:CGRectZero reuseIdentifier:CellIdentifier] autorelease];

 // Set the Accessory Data
 textName = [[[UILabel alloc]initWithFrame:CGRectMake(cell.frame.origin.x, 80, cell.frame.size.width, 20)]autorelease];
 textName.tag     = DATA_TAG;
 textName.textAlignment   = UITextAlignmentCenter;
 textName.backgroundColor  = [UIColor clearColor];
 textName.highlightedTextColor = [UIColor colorWithRed:1.0 green:1.0 blue:0.9 alpha:1.0];
 textName.textColor    = [UIColor colorWithRed:0.0 green:0.0 blue:0.0 alpha:1.0];
 textName.lineBreakMode   = UILineBreakModeWordWrap;

 [cell.contentView addSubview:textName];

 //Set the Image Data
 image = [[[UIImageView alloc]initWithFrame:CGRectMake(cell.frame.origin.x, cell.frame.origin.y, cell.frame.size.width, 80)]autorelease];
 image.tag = IMG_TAG;
 image.contentMode= UIViewContentModeScaleAspectFit;
 [cell.contentView addSubview:image];

}

Accessory* acc= [[AccessoryManager sharedManager].currentList objectAtIndex:indexPath.row];
if(acc == nil)
 return cell;


textName= (UILabel*)[cell.contentView viewWithTag:DATA_TAG];
textName.text= acc.accessoryName;


image= (UIImageView*)[cell.contentView viewWithTag:IMG_TAG];
[image setImage:acc.accessoryImage]; 
return cell;
}

Answer 4

Are you invoking cellForRowAtIndexPath yourself, for example from heightForRowAtIndexPath? If so, you don't need to create the cell to determine its height.