Question

I have a UITableView, and custom cells on it. On cell I have a UILabel, but before I set text to UILabel I did really hard work on text…like find the text in another text, highlight some words on it, and only then I set it to label. So when I scroll my list, it has delay because of this hard work. Any idea how to improve performance ? Maybe to do all hard work in another thread ??

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:
        (NSIndexPath *)indexPath {
static NSString *customCellIdentifier =
    @"CellIdentifier";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:
    customCellIdentifier];
if (cell == nil) {
    NSArray *nib = [[NSBundle mainBundle] loadNibNamed:@"CustomTableRow"
        owner:self options:nil];
    if (nib.count > 0) {
        cell = self.customTableRow;
    }
}

   self.myLabel.text = [self giveMeTheTextThatINeed];

return cell;
}

[self giveMeTheTextThatINeed] – did a hard work on text that takes some time.

Answer 1

Make a new thread for every cell. this thread calls [self giveMeTheTextThatINeed:indexPath], and resets the label(s) in the cell. I’m assuming you can’t get your data any faster, so you want to maintain the scrolling in the table and spin the hard work out to the thread. When the thread is finished, update the cell. You see this a lot in cells with a thumbnail image where the thumbnail only gets uploaded after a while, and is blank or has a placeholder there first.