Rotate images with single tap gesture in XCode - ios

Question

So, I'm working in Xcode 5, OS X Mavericks. I have storyboard with one view in it in my project. Programmatically, I have added about 384 UIImageViews in loop in my view. Here's my code I used for it:
-(void)setImageViewsImages {
[self create Randoms]; //it creates random numbers for definition of rotation direction (rn)
for (i = 0; i < 480; i++) {
currentImage = [[UIImageView alloc] initWithImage:[UIImage imageNamed:#"image.png"]];
currentImage.frame = CGRectMake(x, y, 20, 20);
if (rn == 1) {
CGAffineTransform imageRotation = CGAffineTransformMakeRotation(0);
currentImage.transform = imageRotation;
} else {
switch (rn) {
case 2: {
CGAffineTransform imageRotation = CGAffineTransformMakeRotation(M_PI * 0.5);
currentImage.transform = imageRotation;
}
break;
case 3: {
CGAffineTransform imageRotation = CGAffineTransformMakeRotation(M_PI);
currentImage.transform = imageRotation;
}
break;
case 4: {
CGAffineTransform imageRotation = CGAffineTransformMakeRotation(M_PI * 1.5);
currentImage.transform = imageRotation;
}
break;
}
}
[self.view addSubview:currentImage];
x = x + 20;
if (x == 320) {
x = 0;
y = y + 20;
}
}
}
So, what my question is: I want to add a single tap gesture recognizer onto each created image, and then, when all images are in their places, I want to have opportunity to rotate each image right (or left, it doesn't matter) with single tap on it. I wrote this code, and put it in my loop just before [self.view addSubview:currentImage];, :
UITapGestureRecognizer *singleTap = [[UITapGestureRecognizer alloc] initWithTarget:self
action:#selector(didSingleTap:)];
singleTap.numberOfTapsRequired = 1;
[currentImage addGestureRecognizer:singleTap];
but I can't understand, where to go further.
Thanks for help in advance and sorry for my bad English, hope you will be able to understand it.

Answer 1

Basically the only link you're now missing is an access to the imageView instance from the didSingleTap:. The right way IMO would be subclassing UIImageView, instantiate your subclasses instead and when adding the UITapGestureRecognizer to it calling a method in the subclass instance. Most proper approach would be to delegate the callback back to your view controller like so:
.h
#class RotatingImageView;
#protocol RotatingImageViewDelegate <NSObject>
#required
-(void) rotatingImageViewWasTapped:(RotatingImageView*) rotatingImageView;
#end
#interface RotatingImageView : UIImageView
#property (nonatomic,weak) id<RotatingImageViewDelegate> delegate;
-(void) onTap:(UITapGestureRecognizer*) sender;
#end
.m
#implementation RotatingImageView
- (id)initWithImage:(UIImage *)image
{
self = [super initWithImage:image];
if (self) {
UITapGestureRecognizer *singleTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(onTap:)];
singleTap.numberOfTapsRequired = 1;
[self addGestureRecognizer:singleTap];
}
return self;
}
-(void)onTap:(UITapGestureRecognizer *)sender
{
[self.delegate rotatingImageViewWasTapped:self];
}
#end
your view controller would then implement the RotatingImageViewDelegate protocol, assign itself as a delegate of each RotatingImageView instance and on each tap it would receive the rotatingViewWasTapped: callback with the appropriate image view in the parameter. You could either do the logic directly in the onTap: method inside the subclass or handle it in your view controller.

Answer 2

Why are you recreating the logic of a UICollectionView?
You stated you are on mavericks so iOS 5 support is not an issue.
My advice would be to create a UICollectionViewController, use the UICollectionViewFlowLayout with a itemSize of 20, 20 and create a custom cell.
In the setSelected method, transform the image as such:
- (void)setSelected:(BOOL)selected;
{
[super setSelected:selected];
self.imageView.transform = CGAffineTransformMakeRotation((arc4random() % 4) * M_PI);
}