Implicit Animations - iOS Core Animation - page 150

Listing 7.1 Randomizing the Layer Color
@interface ViewController ()
@property ( nonatomic , weak ) IBOutlet UIView *layerView;
@property ( nonatomic , weak ) IBOutlet CALayer *colorLayer;
@end
@implementation ViewController
- ( void )viewDidLoad
{
[ super viewDidLoad ];
//create sublayer
self .colorLayer = [ CALayer layer ];
self .colorLayer. frame = CGRectMake ( 50.0f , 50.0f , 100.0f , 100.0f );
self .colorLayer. backgroundColor = [ UIColor blueColor ]. CGColor ;
//add it to our view
[ self .layerView. layer addSublayer : self .colorLayer];
}
- ( IBAction )changeColor
{
//randomize the layer background color
CGFloat red = arc4random () / ( CGFloat ) INT_MAX ;
CGFloat green = arc4random () / ( CGFloat ) INT_MAX ;
CGFloat blue = arc4random () / ( CGFloat ) INT_MAX ;
self .colorLayer. backgroundColor = [ UIColor colorWithRed :red
green :green
blue :blue
alpha : 1.0 ]. CGColor ;
}
@end