在Swift中找到最近的UIView的最佳方法

Question

我正在尝试查找最近的可能子视图。在我的应用程序中，有7个UIButton s和一个UILabel s居中以下20的余量。它不是子视图。

我想要什么？用较小的努力找出离按钮最近的标签。

我现在在做什么？我在函数中传递UIButton并计算从该按钮到所有标签的可能距离。然后对距离进行排序会导致上升并选取第一个对象以获得最小距离，这应该是我最近的标签。

internal func findNearByLabel(withRespectToButton button: UIButton) -> UILabel? { 

    var distance = Array<CGFloat>() 
    var labels: Array<UILabel> = self.view.subViews(type: UILabel.self) 

    labels.forEach { (label) in 
     distance.append(self.distance(label.frame.origin, button.frame.origin)) 
    } 

    if !distance.isEmpty { 
     let sortedDistance = Array.init(distance).sorted() 
     let minDistance = sortedDistance.first! 
     let indexOfMinDistance = distance.index(of: minDistance)! 
     return labels[indexOfMinDistance] 
    } 

    return nil 
} 

internal func distance(_ a: CGPoint, _ b: CGPoint) -> CGFloat { 
    let xDistance = a.x - b.x 
    let yDistance = a.y - b.y 
    return CGFloat(sqrt((xDistance * xDistance) + (yDistance * yDistance))) 
} 

extension UIView { 
    func subViews<T : UIView>(type : T.Type) -> [T]{ 
     var all = [T]() 
     for view in self.subviews { 
      if let aView = view as? T{ 
       all.append(aView) 
      } 
     } 
     return all 
    } 
} 

什么是问题？没问题，它的工作原理，但我想检查这是最好的解决方案还是可以改进的？

Answer 1

只是使用功能模式的一些改进。

// generic method, can be in a category 
extension CGPoint { 
    func distance(to point: CGPoint) -> CGFloat { 
     // there is already a function for sqrt(x * x + y * y) 
     return hypot(self.x - point.x, self.y - point.y) 
    } 
} 

internal func findNearByLabel(withRespectToButton button: UIButton) -> UILabel? { 
    // you don't really need the subViews method 
    let labels = self.view.subviews.flatMap { $0 as? UILabel } 
    // don't forget we got "map" 
    let distances = labels.map { $0.frame.origin.distance(to: button.frame.origin) } 

    // we zip both sequences into one, that way we don't have to worry about sorting two arrays 
    let labelDistances = zip(labels, distances) 
    // we don't need sorting just to get the minimum 
    let closestLabel = labelDistances.min { $0.1 < $1.1 } 

    return closestLabel?.0 
}