UITableView scroll is choppy - objective-c

Question

Here is my cellForRowAtIndexPath method. Using ARC in my project.
-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath*)indexPath {
static NSString* cellIdentifier = #"ActivityCell";
UITableViewCell* cell = [tableView dequeueReusableCellWithIdentifier:cellIdentifier];
if (!cell) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:cellIdentifier];
}
Activity* activityToShow = [self.allActivities objectAtIndex:indexPath.row];
//Cell and cell text attributes
cell.textLabel.text = [activityToShow name];
//Slowing down the list scroll, I guess...
LastWeekView* lastWeekView = [[LastWeekView alloc] initWithFrame:CGRectMake(10, 39, 120, 20)];
[lastWeekView setActivity:activityToShow];
lastWeekView.backgroundColor = [UIColor clearColor];
[cell.contentView addSubview:lastWeekView];
return cell;
}
LastWeelView allocation is slowing down the scroll i guess. In the lastWeekView, I fetch relationships of an entity from CoreData, perform a calculation on those values and draw some colors inside its drawRect method.
Here is the drawRect of LastWeekView
- (void)drawRect:(CGRect)rect
{
NSArray* activityChain = self.activity.computeChain; //fetches its relationships data
for (id item in activityChain) {
if (marking == [NSNull null])
{
[notmarkedColor set];
}
else if([(NSNumber*)marking boolValue] == YES)
{
[doneColor set];
}
else if([(NSNumber*)marking boolValue] == NO)
{
[notdoneColor set];
}
rectToFill = CGRectMake(x, y, 10, 10);
CGContextFillEllipseInRect(context, rectToFill);
x = x + dx;
}
}
What can I do to smoothen the scroll of tableView? If I have to asynchronously add this lastWeekView to each cell's contentView, how can i do it? please help.

Answer 1

I'd suggest allocating LastWeekView in cell's allocation scope. Also - fetch all core data objects in viewDidLoad so that in cellForRowAtIndexPath: method would retrieve it from array and not from the store. It should look something like this:
- (void)viewDidLoad
...
_activities = [Activity fetchAllInContext:managedObjectContext];
...
}
-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath*)indexPath {
UITableViewCell *cell = [tableView dequeueReusableCell];
if (!cell) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:cellIdentifier];
LastWeekView* lastWeekView = [[LastWeekView alloc] initWithFrame:CGRectMake(10, 39, 120, 20)];
lastWeekView.backgroundColor = [UIColor clearColor];
[cell.contentView addSubview:lastWeekView];
}
Activity *activityToShow = [_activities objectAtIndex:[indexPath row]];
LastWeekView *lastWeekView = (LastWeekView *)[[[cell contentView] subviews] lastObject];
[lastWeekView setActivity:activityToShow];
return cell;
}
Note that you may also subclass the UITableViewCell to replace contentView with your LastWeekView to quickly access the activity property.