swiftでカスタムviewを追加したviewをdismissすると例外発生

Question

swiftにカスタムview(stateBtn)をaddsubviewして親viewをdismissするとappdelegateでsigabortが発生します。

UserApp[2337:59789] *** Terminating app due to uncaught exception 'NSGenericException', reason: 'Unable to activate constraint with anchors <NSLayoutYAxisAnchor:0x600003e25640 "UserApp.dropDownView:0x7fd7a81dde80.top"> and <NSLayoutYAxisAnchor:0x600003e24340 "UserApp.dropDownBtn:0x7fd7a81dd3a0'神奈川県'.bottom"> because they have no common ancestor. Does the constraint or its anchors reference items in different view hierarchies? That's illegal.'
*** First throw call stack:
省略

libc++abi.dylib: terminating with uncaught exception of type NSException

が発生します。
stateBtnをaddsubviewせずにdismissすると正常に親viewが閉じられます。
この事象を解決する方法はないでしょうか？

開発環境はxcode10.2.1,swift 5.0.1です。

ソースは以下のとおりです。

//// UserEditViewController.swift //////////////////////////////
class UserEditViewController: UIViewController {
var stateBtn: dropDownBtn? = nil

override func viewDidLoad() {
    super.viewDidLoad()

    // Do any additional setup after loading the view.
    stateBtn = dropDownBtn()
    stateBtn = dropDownBtn.init(frame: CGRect(x: 0, y: 0, width: 0, height: 0))

    if let stbtn = self.stateBtn {

　　　　　　　stbtn.translatesAutoresizingMaskIntoConstraints = false

        self.view.addSubview(stbtn)

        stbtn.leftAnchor.constraint(equalTo: self.view.leftAnchor, constant: CGFloat(66)).isActive = true
        stbtn.topAnchor.constraint(equalTo: self.view.topAnchor, constant: CGFloat(373)).isActive = true
        stbtn.widthAnchor.constraint(equalToConstant: 300).isActive = true
        stbtn.heightAnchor.constraint(equalToConstant: 30).isActive = true
    }
}

@IBAction func backTapped(_ sender: Any) {
    self.dismiss(animated: true, completion: nil)
}

//// DropDownList.swift ////////////////////////////////////////////
import UIKit

protocol dropDownProtocol {
func dropDownPressed(string : String)
}

class dropDownBtn: UIButton, dropDownProtocol {

func dropDownPressed(string: String) {
    self.setTitle(string, for: .normal)
    self.dismissDropDown()
}

var dropView = dropDownView()

var height = NSLayoutConstraint()


override init(frame: CGRect) {
    super.init(frame: frame)
    
    self.backgroundColor = UIColor.darkGray
    
    dropView = dropDownView.init(frame: CGRect.init(x: 0, y: 0, width: 0, height: 0))
    dropView.delegate = self
    dropView.translatesAutoresizingMaskIntoConstraints = false
}

override func didMoveToSuperview() {
    self.superview?.addSubview(dropView)
    self.superview?.bringSubviewToFront(dropView)
    dropView.topAnchor.constraint(equalTo: self.bottomAnchor).isActive = true
    dropView.centerXAnchor.constraint(equalTo: self.centerXAnchor).isActive = true
    dropView.widthAnchor.constraint(equalTo: self.widthAnchor).isActive = true
    height = dropView.heightAnchor.constraint(equalToConstant: 0)
}

var isOpen = false
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
    if isOpen == false {
        
        isOpen = true
        
        NSLayoutConstraint.deactivate([self.height])
        
        if self.dropView.tableView.contentSize.height > 150 {
            self.height.constant = 150
        } else {
            self.height.constant = self.dropView.tableView.contentSize.height
        }
        
        
        NSLayoutConstraint.activate([self.height])
        
        UIView.animate(withDuration: 0.5, delay: 0, usingSpringWithDamping: 0.5, initialSpringVelocity: 0.5, options: .curveEaseInOut, animations: {
            self.dropView.layoutIfNeeded()
            self.dropView.center.y += self.dropView.frame.height / 2
        }, completion: nil)
        
    } else {
        isOpen = false
        
        NSLayoutConstraint.deactivate([self.height])
        self.height.constant = 0
        NSLayoutConstraint.activate([self.height])
        UIView.animate(withDuration: 0.5, delay: 0, usingSpringWithDamping: 0.5, initialSpringVelocity: 0.5, options: .curveEaseInOut, animations: {
            self.dropView.center.y -= self.dropView.frame.height / 2
            self.dropView.layoutIfNeeded()
        }, completion: nil)
        
    }
}

func dismissDropDown() {
    isOpen = false
    NSLayoutConstraint.deactivate([self.height])
    self.height.constant = 0
    NSLayoutConstraint.activate([self.height])
    UIView.animate(withDuration: 0.5, delay: 0, usingSpringWithDamping: 0.5, initialSpringVelocity: 0.5, options: .curveEaseInOut, animations: {
        self.dropView.center.y -= self.dropView.frame.height / 2
        self.dropView.layoutIfNeeded()
    }, completion: nil)
}

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

}

class dropDownView: UIView, UITableViewDelegate, UITableViewDataSource {

var dropDownOptions = [String]()

var tableView = UITableView()

var delegate : dropDownProtocol!

override init(frame: CGRect) {
    super.init(frame: frame)
    
    tableView.backgroundColor = UIColor.darkGray
    self.backgroundColor = UIColor.darkGray
    
    
    tableView.delegate = self
    tableView.dataSource = self
    
    tableView.translatesAutoresizingMaskIntoConstraints = false
    
    self.addSubview(tableView)
    
    tableView.leftAnchor.constraint(equalTo: self.leftAnchor).isActive = true
    tableView.rightAnchor.constraint(equalTo: self.rightAnchor).isActive = true
    tableView.topAnchor.constraint(equalTo: self.topAnchor).isActive = true
    tableView.bottomAnchor.constraint(equalTo: self.bottomAnchor).isActive = true
    
}

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

func numberOfSections(in tableView: UITableView) -> Int {
    return 1
}

func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    return dropDownOptions.count
}

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    let cell = UITableViewCell()
    
    cell.textLabel?.text = dropDownOptions[indexPath.row]
    cell.backgroundColor = UIColor.lightGray
    return cell
}

func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
    self.delegate.dropDownPressed(string: dropDownOptions[indexPath.row])
    self.tableView.deselectRow(at: indexPath, animated: true)
}

}

Comments

[MasatoUchida]

読みづらいので質問とは関係ありませんが、markdown記法で修正して頂けると幸いです。

[vanderlvov]

マークダウンのフォーマットの通りに質問を修正してください。
https://teratail.com/help#about-markdown

Answer 1

addSubviewしていないView(dropView)に対して制約を付けようとして落ちています。
didMoveToSuperview()はremove時にも呼ばれます。

Comments

[matsuda2]

ありがとうございます。didMoveToSuperviewを以下のコードに変更して解決しました。

override func didMoveToSuperview() {
if let sview = self.superview {
sview.addSubview(dropView)
sview.bringSubviewToFront(dropView)
dropView.topAnchor.constraint(equalTo: self.bottomAnchor).isActive = true
dropView.centerXAnchor.constraint(equalTo: self.centerXAnchor).isActive = true
dropView.widthAnchor.constraint(equalTo: self.widthAnchor).isActive = true
height = dropView.heightAnchor.constraint(equalToConstant: 0)
}
}