Adding CAAnimation to sublayer in UITableViewCell - ios

Question

I've got a uitableviewcell subclass with an imageView property. Im fetching the image from the web and when i get it, i'd like to crossfade it into the image view.
I've got this CAAnimation code that i was originally using within the view controller to apply this effect. my code looked like this:
CATransition *transition = [CATransition animation];
transition.duration = 0.3f;
transition.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];
transition.type = kCATransitionFade;
[self.photoView.layer addAnimation:transition forKey:someKey];
Now, i'd like to move that code into my UITableViewCell. I've tried applying that animation in various locations but it doesn't seem to be having an affect. I put it in awakeFromNib (the cell is from a nib file) as well as willMoveToSuperview. Any thoughts?

Answer 1

David is right, you're not actually changing the contents of the imageView in your code.
I just made this subclass of an UITableViewCell and added it to a basic iOS Single View application:
#import "AnimatedCell.h"
#implementation AnimatedCell {
BOOL imageWasGrabbed;
}
- (id)initWithStyle:(UITableViewCellStyle)style
reuseIdentifier:(NSString *)reuseIdentifier {
self = [super initWithStyle:style reuseIdentifier:reuseIdentifier];
if (self) {
self.frame = CGRectMake(0,0,320,44);
self.imageView.image = [UIImage imageNamed:#"localImage"];
self.textLabel.text = #"Locally loaded image";
self.layer.borderColor = [UIColor lightGrayColor].CGColor;
self.backgroundColor = [UIColor groupTableViewBackgroundColor];
}
return self;
}
-(void)grabImage {
NSString *path = #"http://www.c4ios.com/images/temp/webImage#2x.png";
NSURL *webImageUrl = [NSURL URLWithString:path];
NSData *webImageData = [NSData dataWithContentsOfURL:webImageUrl];
UIImage *image = [UIImage imageWithData:webImageData];
CATransition *transition = [CATransition animation];
transition.duration = 1.0f;
transition.delegate = self;
NSString *n = kCAMediaTimingFunctionEaseInEaseOut;
transition.timingFunction = [CAMediaTimingFunction functionWithName:n];
transition.type = kCATransitionFade;
[self.imageView.layer addAnimation:transition forKey:#"animateContents"];
self.imageView.image = image;
}
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
if(!imageWasGrabbed) {
[self grabImage];
}
}
-(void)animationDidStop:(CAAnimation *)anim finished:(BOOL)flag {
self.textLabel.text = #"Web loaded image";
imageWasGrabbed = YES;
}
#end
After you add the transition to your cell's imageView layer, you need to call the following:
self.imageView.image = image;
For reference, the View Controller for my project looks like this:
#import "ViewController.h"
#import "AnimatedCell.h"
#implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
AnimatedCell *cell = [[AnimatedCell alloc]
initWithStyle:UITableViewCellStyleDefault
reuseIdentifier:#"AnimatedCell"];
cell.center = self.view.center;
[self.view addSubview:cell];
}
#end