view.center命令后子视图框架未更新

Question

我有这些不同的视图，如图所示：主视图是container，内部是boxSentence，在boxSentence内部，是subView，在subView内部，带有灰色框boxWord的不同文本标签。然后是另一个视图boxAnswer，它是我创建的可拖动元素，只能拖放到boxWord内部（我将boxWord传递给了boxAnswer的自定义类，以检查其位置（帧） ）。

在这种情况下，一切正常，只能放置boxAnswer在盒子里Word

然后用于调整整个视图的图形，我想将我的subView及其所有实际子视图放在boxSentence的中心。为此，我使用了subView.center = boxSentence.center，并获得了想要的东西。

[现在，问题出在我尝试将boxAnswer拖放到boxWord的新位置内时，它不起作用，但是如果我尝试将其拖放到boxWord的位置之前，它工作的中心。

似乎当您执行subView.center = boxSentence.center时，它仅影响subView的框架，但不影响其子视图的框架。有关如何解决问题的任何建议？

CODE：

// creo box dove inserire la frase
let boxSentence = UIView(frame: CGRect(x: 0, y: 0, width: container.frame.width, height: container.frame.height/2))
container.addSubview(boxSentence)
boxSentence.backgroundColor = hexStringToUIColor(hex: "#49eb34")

let subView = UIView(frame: CGRect(x: 0, y: 0, width: container.frame.width, height: 70))


let label1 = UILabel(frame: CGRect(x: 0, y: 0, width: 100, height: 100))
label1.text = esercizio.ctsex![0].first_sentence
label1.backgroundColor = UIColor.yellow
label1.sizeToFit()

let boxWord = UIView(frame: CGRect(x: label1.frame.maxX, y: 0, width: 100, height: 60))
boxWord.backgroundColor = UIColor.gray

let label2 = UILabel(frame: CGRect(x: boxWord.frame.maxX, y: 0, width: 100, height: 100))
label2.text = esercizio.ctsex![0].second_sentence
label2.backgroundColor = UIColor.yellow
label2.sizeToFit()

subView.addSubview(label1)
subView.addSubview(boxWord)
subView.addSubview(label2)
subView.backgroundColor = UIColor.purple
boxSentence.addSubview(sottoView)
subView.frame = CGRect(x: 0, y: 0, width: label2.frame.maxX-label1.frame.minX, height: 80)
subView.center = boxSentence.center


let coordrisposta = CGRect(x: boxFrase.frame.minX, y: boxFrase.frame.maxY, width: 80.0, height: 40.0)
let boxAnswer = DragObject(frame: coordrisposta, vistap: boxWord)
boxAnswer.backgroundColor = UIColor.red

container.addSubview(rispostaBox)

CLASS DragObject OF boxAnser：

import UIKit

// CLASSE CHE CREA UNA VISTA CHE PUO ESSERE SPOSTATA SOLO ALL'INTERNO DI UNA VISTA PASSATA DA PARAMETRO

class DragObject: UIView {

    var vista: UIView
    var initcoord: CGRect

    init(frame: CGRect, vistap: UIView){
        self.vista = vistap
        self.initcoord = frame
        super.init(frame: frame)
    }

    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
        print("touch began")
    }

    override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {
       var touch : UITouch! = touches.first as UITouch?
       self.center = touch.location(in: self.superview)        
    }

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

        var coorv = vista.frame
        print(coorv)

        let coord1 = (touches.first?.location(in: self.superview))!
        let destinazione1 = CGPoint(x: coorv.minX, y: coorv.minY)
        let destinazione2 = CGPoint(x: coorv.maxX, y: coorv.maxY)

        if coord1.x > destinazione1.x && coord1.y > destinazione1.y && coord1.x < destinazione2.x && coord1.y < destinazione2.y {
            print("OK")
            self.frame = vista.frame
        } else {
            print("fuori")
            self.frame = initcoord
        }
    }
}

Answer 1

UIView的框架是相对于其父边界的坐标（UIView的内部坐标系是该视图的子视图的坐标系）。例如，我们有2个视图的UIViewController：

let redView = UIView()
redView.backgroundColor = .red
redView.frame = CGRect(x: 20, y: 20, width: 100, height: 100)
self.view.addSubview(redView)

let greenView = UIView()
greenView.backgroundColor = .green
greenView.frame = CGRect(x: 25, y:25, width:50, height: 50)
redView.addSubview(greenView)

print(redView.frame)
/*
(20.0, 20.0, 100.0, 100.0)
redView is placed self.view.bounds.origin.x + 20 and self.view.bounds.origin.y + 20
*/
print(greenView.frame)
/*
(25.0, 25.0, 50.0, 50.0)
green is placed redView.bounds.origin.x + 25 and redView.bounds.origin.y + 25
*/
print(redView.convert(greenView.frame, to: self.view))
/*
(45.0, 45.0, 50.0, 50.0)
converted frame of greenView from redViews bounds to of self.view bounds.
*/

所以在DragObject内部的问题是，传递框架和视图坐标，以反映它们相对于subView视图原点的位置。同时，DragObject是容器视图的子视图，当您收到触摸坐标时，您将获得相对于容器视图的坐标。您可以通过将vista.frame转换为DragObject Superview坐标系来解决此问题。这是DragObject中的重写func touchesEnded（_ touches：Set，带有事件：UIEvent？）的完整代码。
var coorv = vista.superview!.convert(vista.frame, to: self.superview!)
print(coorv)

let coord1 = (touches.first?.location(in: self.superview))!
let destinazione1 = CGPoint(x: coorv.minX, y: coorv.minY)
let destinazione2 = CGPoint(x: coorv.maxX, y: coorv.maxY)

if coord1.x > destinazione1.x && coord1.y > destinazione1.y && coord1.x < destinazione2.x && coord1.y < destinazione2.y {
    print("OK")
    self.frame = coorv
} else {
    print("fuori")
    self.frame = initcoord
}