使用委托将数据从UIView子类发送到UIViewController

问题描述

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.而我所拥有的如下.

I have an IBOutlet-connected UIView object (innerView) sitting over view controller (UIViewController)'s view. I want to let the user rotate innerView with their finger. So I have a subclass (TouchView) of UIView set to innerView's class. As the user rotates the view object, I want the view controller to receive a value from TouchView. And what I have is the following.

// 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，视图控制器从不接收来自TouchView的委托调用.我究竟做错了什么?谢谢您的帮助.

Well, the view controller never receives a delegate call from TouchView. What am I doing wrong? Thank you for your help.

推荐答案

我看到2个问题

1. 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
2. 您的innerView不是touchView的实例，并且未设置其委托

我对您情况的处理方式如下:

My approach to your situation would look something like this:

// 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
    }
}

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