Debugging app artwork slow down in Objective-C - iphone

Question

I have a tableviewcontroller, specifically, in my app which is getting a little jittery when scrolling.
I fairly certain it's because of my custom UISegmentedControl appearance, I have four in my table, each in their own cell.
I use this code in my app delegate to customise them:
[[UISegmentedControl appearance] setBackgroundImage:[[UIImage imageNamed:#"SegmentedControl.png"] resizableImageWithCapInsets:UIEdgeInsetsMake(0, 4, 0, 4)] forState:UIControlStateNormal barMetrics:UIBarMetricsDefault];
[[UISegmentedControl appearance] setBackgroundImage:[[UIImage imageNamed:#"SegmentedControlSelected.png"] resizableImageWithCapInsets:UIEdgeInsetsMake(0, 4, 0, 4)] forState:UIControlStateSelected barMetrics:UIBarMetricsDefault];
[[UISegmentedControl appearance] setDividerImage:[UIImage imageNamed:#"SegmentedControlDivider.png"] forLeftSegmentState:UIControlStateNormal rightSegmentState:UIControlStateNormal barMetrics:UIBarMetricsDefault];
[[UISegmentedControl appearance] setDividerImage:[UIImage imageNamed:#"SegmentedControlSelectedDivider.png"] forLeftSegmentState:UIControlStateSelected rightSegmentState:UIControlStateNormal barMetrics:UIBarMetricsDefault];
[[UISegmentedControl appearance] setDividerImage:[UIImage imageNamed:#"SegmentedControlSelectedDivider.png"] forLeftSegmentState:UIControlStateNormal rightSegmentState:UIControlStateSelected barMetrics:UIBarMetricsDefault];
[[UISegmentedControl appearance] setTitleTextAttributes:[NSDictionary dictionaryWithObjectsAndKeys:
[UIColor whiteColor], UITextAttributeTextColor,
[UIColor grayColor], UITextAttributeTextShadowColor,
[NSValue valueWithUIOffset:UIOffsetMake(0, -1)], UITextAttributeTextShadowOffset,
[UIFont fontWithName:#"Georgia-Italic" size:0.0], UITextAttributeFont,
nil] forState:UIControlStateNormal];
Why might this cause such a slow down? What could I do to improve performance? It jitters as they come onto the screen. I have never had a problem like this before.
I'm fairly sure its the switches and segmented controls, as when I remove them it speeds up and goes all silky smooth. I basically do this:
if (indexPath.row == 0)
{
cell.textLabel.text = #"text";
UISegmentedControl *segControl = [[UISegmentedControl alloc] initWithItems:[NSArray arrayWithObjects:#"1", #"2", nil]];
[segControl setSelectedSegmentIndex:[myBool boolValue]];
[segControl setSegmentedControlStyle:UISegmentedControlStyleBar];
[segControl addTarget:self action:#selector(myMethod:) forControlEvents:UIControlEventValueChanged];
cell.accessoryView = segControl;
}
In my cellForRowAtIndexPath 7 times, how can I make this faster?

Answer 1

I have an app that I am working on and I had some similar customizations. I recommend reusing the set controls... You can accomplish this by making a UITableViewCell subclass and setting up your seg control in it, then you can create outlets for the things you need to customize.
A quick search found this tutorial and it looks like what I am talking about
UITableViewCell Prototype Tutorial
This way your cells will be completely reusable and therefore, much faster.
But then, I don't now your exact use case, so maybe this won't apply to you. It sped up my cells with custom buttons, art, and animations quite a bit.
Just remember alloc inits are very slow.
I guess another option would be to pre-init all that you can with the controls and maybe store them in and array then only load them in cellForRowAtIndexPath: