ios - 使用委托(delegate)将数据从UIView子类发送到UIViewController

我有一个连接IBOutlet的UIView对象(innerView)，它位于视图控制器(UIViewController)的视图上方。我想让用户用手指旋转innerView。因此，我将UIView的子类(TouchView)设置为innerView的类。当用户旋转视图对象时，我希望视图控制器从TouchView接收一个值。我所拥有的如下。

// UIView
protocol TouchDelegate: class {
    func degreeChanged(degree: Double)
}

class TouchView: UIView {
    weak var delegate: TouchDelegate? = nil
    override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {
        let aTouch: AnyObject = touches.first! as UITouch
        let newLoc = aTouch.location(in: self.superview)

        ...
        ...

        let degree = { (radians: Double) -> Double in
            return radians * 180 / M_PI
        }
        self.delegate?.degreeChanged(degree: degree)
    }
}

// UIViewController
class ViewController: UIViewController, TouchDelegate {
    @IBOutlet weak var innerView: UIView!

    // MARK: - View
    override func viewDidLoad() {
        super.viewDidLoad()
        let touchView = TouchView()
        touchView.delegate = self
    }

    // MARK: - From TouchView
    func degreeChanged(degree: Double) {
        print(degree) // <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< no call
    }
}

好吧，视图控制器永远不会收到来自TouchView的委托调用。我究竟做错了什么？感谢您的帮助。

最佳答案

我看到两个问题

您创建了touchView的新实例，但未将其添加到视图控制器的视图中

您的innerView不是touchView的实例，并且其委托未设置

我对您的情况的处理方式如下所示:

// UIViewController
class ViewController: UIViewController, TouchDelegate {
@IBOutlet weak var innerView: TouchView!

// MARK: - View
override func viewDidLoad() {
    super.viewDidLoad()
    innerView.delegate = self
}

    // MARK: - From TouchView
    func degreeChanged(degree: Double) {
        print(degree) // <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< no call
    }
}