How to avoid data being copied to UITableViewCell? - objective-c

Question

I have an array with charts that I would like to display in a table view. Since drawing the charts takes a few milli seconds, which would make scrolling choppy, I would like to remove the old chart from cell.contentView of a re-used cell and add a new subview with the correct chart when scrolling (see source code below). This works: the charts are correctly displayed.
However, when adding the subviews, the used memory increases and scrolling the first time down is choppy (scrolling is not choppy after all rows were displayed once).
It seems that the chart data, which is already stored in an instance variable (strong) is copied (not just a reference) into the UITableViewCell.
I would like to avoid this so that less memory is used.
Summary: How can I avoid it that my charts are being copied into a UITableViewCell when using addSubview. Instead, I would like to add just a reference to my data when using addSubview.
static NSString *CellIdentifier = #"chart";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell==nil)
{
cell = [[UITableViewCell alloc]
initWithStyle:UITableViewCellStyleDefault
reuseIdentifier:CellIdentifier];
}
[cell.contentView.subviews makeObjectsPerformSelector:#selector(removeFromSuperview)];
VMKChartData *chartData = [shinobiCharts_ objectAtIndex:rowNumber];
ShinobiChart *shinobiChart = chartData.shinobiChart;
[cell.contentView addSubview:shinobiChart];
[self setSeparatorInsets:cell];
return cell;

Answer 1

Don't use a plain UITableViewCell and addSubview:, but create a custom table view subclass that has a property #property (nonatomic, weak) UIView *chartView, in tableView:cellForRowAtIndexPath: just assign it.
cell.chartView = shinobiChart;
in the setter for chartView, add it to the content view.
-(void)setChartView:(UIView *)chartView
{
[_chartView removeFromSuperview];
_chartView = chartView;
[self.contentView addSubView:chartView];
}