I have created Circle using "draw" and can place it anywhere on view. but when I want to move a specific circle by clicking it. it selects "LAST" created circle. how can I select a specific circle? please guide me for the same. if anything else you need let me know.

**CircleView**
import UIKit

class CircleView: UIView {

    override init(frame: CGRect) {
        super.init(frame: frame)
        backgroundColor = .clear
    }


    required init(coder aDecoder : NSCoder) {
        fatalError("init(coder : ) has not been implemented")
    }

    override func draw(_ rect: CGRect) {
        if let context = UIGraphicsGetCurrentContext(){

            context.setLineWidth(2)
            UIColor.yellow.set()


            let circleCenter = CGPoint(x: frame.size.width / 2, y: frame.self.height / 2)
            let circleRadius = (frame.size.width - 10) / 2

            context.addArc(center: circleCenter, radius: circleRadius, startAngle: 0, endAngle: .pi * 2, clockwise: true)

            context.strokePath()
        }
    }


}

**ViewController**
import UIKit

class ViewController: UIViewController {


    var circleView = CircleView(frame: CGRect(x: 0, y: 0, width: 0, height: 0))
    let circleWidth = CGFloat(100)
    var lastCircleCenter = CGPoint()
    var currentCenter = CGPoint()

    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = UIColor.lightGray
        circleView.isUserInteractionEnabled = true
    }


    override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
        if let touch = touches.first{
            lastCircleCenter  = touch.location(in: view)
        }
    }

    override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {

        if let touch = touches.first{
            let circleCenter = touch.location(in: view)

            if circleCenter == lastCircleCenter{

            let circleHeight = circleWidth

            circleView = CircleView(frame: CGRect(x: circleCenter.x - circleWidth / 2, y: circleCenter.y - circleWidth / 2, width: 100, height: 100))

                view.addSubview(circleView)
            }
        }
    }

    override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {

        guard let touch = touches.first else {
            return
        }
        let location = touch.location(in: view)
        circleView.center = location
    }

}

how can I select a specific circle? please guide me for the same. if anything else you need let me know. how can I select a specific circle? please guide me for the same. if anything else you need let me know.

CodePudding user response：

If you are creating multiple circles and adding them to your view, I would suggest to keep track of the created circles in a collection. That way on each touch you can check if the coordinate matches any of the created circles. Based on that you can determine if to create a new circle or to move an existing one.

Example:

class ViewController: UIViewController {
    var circleViews: [CircleView] = []
    let circleWidth = CGFloat(100)
    var draggedCircle: CircleView?

    override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
        // Do nothing if a circle is being dragged
        // or if we do not have a coordinate
        guard draggedCircle == nil, let point = touches.first?.location(in: view) else {
            return
        }

        // Do not create new circle if touch is in an existing circle
        // Keep the reference of the (potentially) dragged circle
        if let draggedCircle = circleViews.filter({ UIBezierPath(ovalIn: $0.frame).contains(point) }).first {
            self.draggedCircle = draggedCircle
            return
        }

        // Create new circle and store in an array
        let offset = circleWidth / 2
        let rect = CGRect(x: point.x - offset, y: point.y - offset, width: circleWidth, height: circleWidth)
        let circleView = CircleView(frame: rect)
        circleViews.append(circleView)
        view.addSubview(circleView)
        // The newly created view can be immediately dragged
        draggedCircle = circleView
    }

    override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
        // If touches end then a circle is never dragged
        draggedCircle = nil
    }

    override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {
        guard let draggedCircle = draggedCircle, let point = touches.first?.location(in: view) else {
            return
        }

        draggedCircle.center = point
    }
}