Program multiple animations for single UIImageView with image change - ios

Question

I need to animate a UIImageView inside my application, and cyclically change the UIImage inside it, making it look like an animated photo slideshow.
Right now I'm using an NSTimer to fire every N seconds the UIImage change and the animation itself:
- (void)viewDidLoad {
// NSArray initialization
NSTimer *timer = [NSTimer timerWithTimeInterval:16
target:self
selector:#selector(onTimer)
userInfo:nil
repeats:YES];
[[NSRunLoop currentRunLoop] addTimer:timer forMode:NSDefaultRunLoopMode];
[timer fire];
[super viewDidLoad];
}
This is the onTimer selector code:
- (void) onTimer {
// cycle through max 9 images
if(imageIndex > 8)
imageIndex = 0;
// set the image
[_imageContainer setImage:[images objectAtIndex:imageIndex]];
// reset width and height of the UIImage frame
CGRect frame = [_imageContainer frame];
frame.size.width -= 170.0f;
frame.size.height -= 100.0f;
[_imageContainer setFrame:frame];
// fade in
[UIView animateKeyframesWithDuration:2.0f delay:0.0f options:0 animations:^{
[_imageContainer setAlpha:1];
} completion:^(BOOL finished) {
// image movement
[UIView animateKeyframesWithDuration:12.0f delay:0.0f options:0 animations:^{
CGRect frame = [_imageContainer frame];
frame.size.width += 170.0f;
frame.size.height += 100.0f;
[_imageContainer setFrame:frame];
} completion:^(BOOL finished) {
// fade out
[UIView animateKeyframesWithDuration:2.0f delay:0.0f options:0 animations:^{
[_imageContainer setAlpha:0];
} completion:nil];
}];
}];
imageIndex++;
}
This seem a very raw but "working" way to achieve what I want but I recognize it might not be the ideal way.
Is there any better method to achieve what I'm looking for?

Answer 1

Updated Answer For Fade Animation
- (void)viewDidLoad
{
[super viewDidLoad];
// self.animationImages is your Image Array
self.animationImages = #[[UIImage imageNamed:#"Image1"], [UIImage imageNamed:#"Image2"]];
// make the first call
[self animateImages];
}
- (void)animateImages
{
static int count = 0;
UIImage *image = [self.animationImages objectAtIndex:(count % [animationImages count])];
[UIView transitionWithView:self.animationImageView
duration:1.0f // animation duration
options:UIViewAnimationOptionTransitionCrossDissolve
animations:^{
self.animationImageView.image = image; // change to other image
} completion:^(BOOL finished) {
[self animateImages]; // once finished, repeat again
count++; // this is to keep the reference of which image should be loaded next
}];
}