ios - 自定义 UIButton .touchDragEnter 和 .touchDragExit 区域/大小？

Question

是否可以从被认为是 .touchDragExit(或 .touchDragEnter)的按钮自定义区域(超出其可选区域？)？

更具体地说，我说的是这种情况:我点击 UIButton，.touchDown 被调用，然后我开始将我的手指从按钮上拖开，在某个点(一段距离)它将不再选择(当然我可以拖回去选择...)。我想要修改那个距离...

这可能吗？

Answer 1

您需要覆盖 UIButton continueTracking 和 touchesEnded 函数。

改编@Dean的链接，实现如下(swift 4.2):

class ViewController: UIViewController {

    @IBOutlet weak var button: DragButton!

    override func viewDidLoad() {
        super.viewDidLoad()
    }

}

class DragButton: UIButton {

    private let _boundsExtension: CGFloat = 0 // Adjust this as needed

    override open func continueTracking(_ touch: UITouch, with event: UIEvent?) -> Bool {

        let outerBounds: CGRect = bounds.insetBy(dx: CGFloat(-1 * _boundsExtension), dy: CGFloat(-1 * _boundsExtension))

        let currentLocation: CGPoint = touch.location(in: self)
        let previousLocation: CGPoint = touch.previousLocation(in: self)

        let touchOutside: Bool = !outerBounds.contains(currentLocation)
        if touchOutside {
            let previousTouchInside: Bool = outerBounds.contains(previousLocation)
            if previousTouchInside {
                print("touchDragExit")
                sendActions(for: .touchDragExit)
            } else {
                print("touchDragOutside")
                sendActions(for: .touchDragOutside)
            }
        } else {
            let previousTouchOutside: Bool = !outerBounds.contains(previousLocation)
            if previousTouchOutside {
                print("touchDragEnter")
                sendActions(for: .touchDragEnter)
            } else {
                print("touchDragInside")
                sendActions(for: .touchDragInside)
            }
        }

        return true
    }

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

        let touch: UITouch = touches.first!
        let outerBounds: CGRect = bounds.insetBy(dx: CGFloat(-1 * _boundsExtension), dy: CGFloat(-1 * _boundsExtension))

        let currentLocation: CGPoint = touch.location(in: self)

        let touchInside: Bool = outerBounds.contains(currentLocation)
        if touchInside {
            print("touchUpInside action")
            return sendActions(for: .touchUpInside)
        } else {
            print("touchUpOutside action")
            return sendActions(for: .touchUpOutside)
        }
    }
}

尝试更改 _boundsExtension 值