@interface ViewController ()@property (nonatomic, weak) IBOutlet UIImageView *hourHand;
@property (nonatomic, weak) IBOutlet UIImageView *minuteHand;
@property (nonatomic, weak) IBOutlet UIImageView *secondHand;
@property (nonatomic, weak) NSTimer *timer;@end@implementation ViewController- (void)viewDidLoad
{[super viewDidLoad];//start timerself.timer = [NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:@selector(tick) userInfo:nil repeats:YES];//set initial hand positions[self tick];
}- (void)tick
{//convert time to hours, minutes and secondsNSCalendar *calendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];NSUInteger units = NSHourCalendarUnit | NSMinuteCalendarUnit | NSSecondCalendarUnit;NSDateComponents *components = [calendar components:units fromDate:[NSDate date]];CGFloat hoursAngle = (components.hour / 12.0) * M_PI * 2.0;//calculate hour hand angle //calculate minute hand angleCGFloat minsAngle = (components.minute / 60.0) * M_PI * 2.0;//calculate second hand angleCGFloat secsAngle = (components.second / 60.0) * M_PI * 2.0;//rotate handsself.hourHand.transform = CGAffineTransformMakeRotation(hoursAngle);self.minuteHand.transform = CGAffineTransformMakeRotation(minsAngle);self.secondHand.transform = CGAffineTransformMakeRotation(secsAngle);
}@end

- (void)viewDidLoad
{[super viewDidLoad];// adjust anchor pointsself.secondHand.layer.anchorPoint = CGPointMake(0.5f, 0.9f); self.minuteHand.layer.anchorPoint = CGPointMake(0.5f, 0.9f); self.hourHand.layer.anchorPoint = CGPointMake(0.5f, 0.9f);// start timer
} 

@interface ViewController ()@property (nonatomic, weak) IBOutlet UIView *greenView;
@property (nonatomic, weak) IBOutlet UIView *redView;@end@implementation ViewController- (void)viewDidLoad
{[super viewDidLoad];//move the green view zPosition nearer to the cameraself.greenView.layer.zPosition = 1.0f;
}
@end

@interface ViewController ()@property (nonatomic, weak) IBOutlet UIView *layerView;
@property (nonatomic, weak) CALayer *blueLayer;@end@implementation ViewController- (void)viewDidLoad
{[super viewDidLoad];//create sublayerself.blueLayer = [CALayer layer];self.blueLayer.frame = CGRectMake(50.0f, 50.0f, 100.0f, 100.0f);self.blueLayer.backgroundColor = [UIColor blueColor].CGColor;//add it to our view[self.layerView.layer addSublayer:self.blueLayer];
}- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{//get touch position relative to main viewCGPoint point = [[touches anyObject] locationInView:self.view];//convert point to the white layer's coordinatespoint = [self.layerView.layer convertPoint:point fromLayer:self.view.layer];//get layer using containsPoint:if ([self.layerView.layer containsPoint:point]) {//convert point to blueLayer’s coordinatespoint = [self.blueLayer convertPoint:point fromLayer:self.layerView.layer];if ([self.blueLayer containsPoint:point]) {[[[UIAlertView alloc] initWithTitle:@"Inside Blue Layer" message:nildelegate:nil cancelButtonTitle:@"OK"otherButtonTitles:nil] show];} else {[[[UIAlertView alloc] initWithTitle:@"Inside White Layer"message:nil delegate:nilcancelButtonTitle:@"OK"otherButtonTitles:nil] show];}}
}@end

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{//get touch positionCGPoint point = [[touches anyObject] locationInView:self.view];//get touched layerCALayer *layer = [self.layerView.layer hitTest:point];//get layer using hitTestif (layer == self.blueLayer) {[[[UIAlertView alloc] initWithTitle:@"Inside Blue Layer"message:nildelegate:nilcancelButtonTitle:@"OK"otherButtonTitles:nil] show];} else if (layer == self.layerView.layer) {[[[UIAlertView alloc] initWithTitle:@"Inside White Layer"message:nildelegate:nilcancelButtonTitle:@"OK"otherButtonTitles:nil] show];}
}