ios - 如何删除某种类型的所有 subview

Question

我有一张疼痛图，我在其中使用位置坐标来绘制疼痛部位。我可以在 for in 循环中添加“点”，它们显示得很好。但是，在 for in 循环之外实例化它们之前，我无法删除它们。因此，每次我更新 View 时，它都会绘制新 View ，而不是在旧 View 之上绘制新 View 。我能做什么？

这个版本很好地添加了点，但是我不能在外面删除它们，因为我不能调用 dot.removeFromSuperview()

DispatchQueue.global(qos: .background).async {
      if let locationNotNilX = self.painDiagramAnalysisModel.painLocationXFor(days: self.daysChosen){
        x = locationNotNilX
        count = locationNotNilX.count
      }

      if let locationNotNilY = self.painDiagramAnalysisModel.painLocationYFor(days: self.daysChosen){
        y = locationNotNilY
      }

      let locationsArray = zip(x, y)
      print("zipped array \(locationsArray)")
      DispatchQueue.main.async {
        let dot = UIImageView()
        dot.removeFromSuperview()
        dot.image = nil
        for item in locationsArray {
          self.locationPainY = (diagramHeight * CGFloat(item.1)) + originY
          self.locationPainX = (diagramWidth * CGFloat(item.0)) + originX
          print(" locationX \(self.locationPainX) locationY  \(self.locationPainY)")
          dot.image = UIImage(named: "dot")
          dot.frame = CGRect(x: self.locationPainX - (dotDiameter / 4), y: self.locationPainY - (dotDiameter / 4), width: dotDiameter , height: dotDiameter)

          if count > 2 {
            dot.alpha = 0.6
          } else {
        dot.alpha = 1.0
          }
          dot.readingsPressedAnimation()

          self.view.addSubview(dot)
        }
      }
    }

此版本删除了点，但只有一个点(self 卡在点上，只在 for in 循环中实例化一次。

let dot = UIImageView()
    dot.removeFromSuperview()
    dot.image = nil

    DispatchQueue.global(qos: .background).async {
       if let locationNotNilX = self.painDiagramAnalysisModel.painLocationXFor(days: self.daysChosen){
        x = locationNotNilX
        count = locationNotNilX.count
      }

      if let locationNotNilY = self.painDiagramAnalysisModel.painLocationYFor(days: self.daysChosen){
        y = locationNotNilY
      }

      let locationsArray = zip(x, y)
      print("zipped array \(locationsArray)")
      DispatchQueue.main.async {

        for item in locationsArray {
          self.locationPainY = (diagramHeight * CGFloat(item.1)) + originY
          self.locationPainX = (diagramWidth * CGFloat(item.0)) + originX
          print(" locationX \(self.locationPainX) locationY  \(self.locationPainY)")
          dot.image = UIImage(named: "dot")
          dot.frame = CGRect(x: self.locationPainX - (dotDiameter / 4), y: self.locationPainY - (dotDiameter / 4), width: dotDiameter , height: dotDiameter)

          if count > 2 {
            dot.alpha = 0.6
          } else {
            dot.alpha = 1.0
          }
          dot.readingsPressedAnimation()

          self.view.addSubview(dot)
        }
      }
    }

如何在循环外添加点的多个实例并将它们移除？

Answer 1

遍历您的 map subview 并删除所有 UIImageViews:

func removeDots() {
    for case let dot as UIImageView in yourPainMapView.subViews {
        dot.removeFromSuperView()
    }
}

如果您正在使用其他不想删除的 UIImageView subview ，子类 UIImageView (class MyDot:UIImage {...}):

for case let dot as MyDot in yourPainMapView.subViews