查找相同的UIImageView类是否相交

Question

I created a subclass of UIimageView because i want to use this imageview multiple times. I'm using touchesmoved to drag the image. So when i use multiple images of same class, i want to find whether they intersect each other. Here's the image class code

 import UIKit

    class imgBall: UIImageView {

        private var xOffset: CGFloat = 0.0
        private var yOffset: CGFloat = 0.0

        required init(coder aDecoder:NSCoder) {
            fatalError("use init(point:")
        }


        init(point:CGPoint) {
            let image = UIImage(named: "ball.png")!
            super.init(image:image)

            self.frame = CGRect(origin: point, size: CGSize(width: 100, height: 100))
            self.userInteractionEnabled = true
        }

        override func touchesBegan(touches: NSSet, withEvent event: UIEvent) {
            let point = touches.anyObject()!.locationInView(self.superview)
            xOffset = point.x - self.center.x
            yOffset = point.y - self.center.y

        }

        override func touchesMoved(touches: NSSet, withEvent event: UIEvent) {
            let point = touches.anyObject()!.locationInView(self.superview)
            self.center.x = point.x - xOffset        
        }
    }

and this is how I'm using it in gameviewcontroller

viewDidLoad() {

var ball1 = imgBall(point: CGPoint(x: 20, y: 0))
self.view.addSubview(ball1)

var ball2 = imgBall(point: CGPoint(x: 50, y: 70))
self.view.addSubview(ball2)

}

so how do i find out if they intersect/collide each other?

Answer 1

You've got to use CGRectIntersectsRect with something like this :

if (CGRectIntersectsRect(ball1.frame,ball2.frame) {
    // they intersect
} else {
    // they're safe
}