UIButtonが

Question

こんにちは動作しないカスタムに制約を追加するI持って次のコード：だから基本的に私は、幅と高さの制約を持つ2つのボタンを追加している、と私はcancelButtonを設定

class MyController {  
    override func viewDidLoad() { 
     self.addButtons() 

     super.viewDidLoad() 
    } 

    func addButtons() { 
     let cancelButton = UIButton(type: .custom) 
     let validateButton = UIButton(type: .custom) 

     cancelButton.setImage(UIImage(named: "cancel_icon"), for: .normal) 
     validateButton.setImage(UIImage(named: "validate_icon"), for: .normal) 

     cancelButton.addTarget(self, action: #selector(cancelAction), for: .touchUpInside) 
     validateButton.addTarget(self, action: #selector(validateAction), for: .touchUpInside) 

     cancelButton.translatesAutoresizingMaskIntoConstraints = false 
     validateButton.translatesAutoresizingMaskIntoConstraints = false 

     self.view.addSubview(cancelButton) 
     self.view.addSubview(validateButton) 

     let leftCancel = NSLayoutConstraint(item: cancelButton, attribute: .leading, relatedBy: .equal, toItem: self.view, attribute: .leading, multiplier: 1, constant: 16) 
     let bottomCancel = NSLayoutConstraint(item: cancelButton, attribute: .bottom, relatedBy: .equal, toItem: self.view, attribute: .bottom, multiplier: 1, constant: 20) 
     let widthCancel = NSLayoutConstraint(item: cancelButton, attribute: .width, relatedBy: .equal, toItem: nil, attribute: .notAnAttribute, multiplier: 1, constant: 20) 
     let heightCancel = NSLayoutConstraint(item: cancelButton, attribute: .height, relatedBy: .equal, toItem: nil, attribute: .notAnAttribute, multiplier: 1, constant: 20) 
     let rightValidate = NSLayoutConstraint(item: validateButton, attribute: .trailing, relatedBy: .equal, toItem: self.view, attribute: .trailing, multiplier: 1, constant: 16) 
     let bottomValidate = NSLayoutConstraint(item: validateButton, attribute: .bottom, relatedBy: .equal, toItem: self.view, attribute: .bottom, multiplier: 1, constant: 20) 
     let widthValidate = NSLayoutConstraint(item: validateButton, attribute: .width, relatedBy: .equal, toItem: nil, attribute: .notAnAttribute, multiplier: 1, constant: 20) 
     let heightValidate = NSLayoutConstraint(item: validateButton, attribute: .height, relatedBy: .equal, toItem: nil, attribute: .notAnAttribute, multiplier: 1, constant: 20) 
     NSLayoutConstraint.activate([leftCancel, bottomCancel, rightValidate, bottomValidate, widthCancel, heightCancel, widthValidate, heightValidate]) 

     self.view.layoutIfNeeded() 
    } 

    func cancelAction() { 
     self.dismiss(animated: true, completion: nil) 
    } 

    func validateAction() { 
     self.dismiss(animated: true, completion: nil) 
    } 
} 

左下にはvalidateButtonが表示されます。

マイボタンが表示されません。ボタンのフレームをこのように設定すると、それは機能します：

cancelButton.frame = CGRect(x: 16, y: self.view.frame.height - 40, width: 20, height: 20) 
validateButton.frame = CGRect(x: self.view.frame.width - 36, y: self.view.frame.height - 40, width: 20, height: 20) 

誰かが私の制約に間違いを知っていますか？ ありがとう！

Answer 1

はVisualFormatは、その用途がありますが、それはまた、独自の癖がある - そのような要素間の柔軟な間隔とします。ここでVisualFormatのないソリューションです：

//: Playground - noun: a place where people can play 

import UIKit 

import PlaygroundSupport 

class MyController: UIViewController { 
    override func viewDidLoad() { 
     super.viewDidLoad() 

     self.addButtons() 
    } 

    func addButtons() { 
     let cancelButton = UIButton(type: .custom) 
     let validateButton = UIButton(type: .custom) 

     cancelButton.setImage(UIImage(named: "cancel_icon"), for: .normal) 
     validateButton.setImage(UIImage(named: "validate_icon"), for: .normal) 

     cancelButton.addTarget(self, action: #selector(cancelAction), for: .touchUpInside) 
     validateButton.addTarget(self, action: #selector(validateAction), for: .touchUpInside) 

     cancelButton.translatesAutoresizingMaskIntoConstraints = false 
     validateButton.translatesAutoresizingMaskIntoConstraints = false 

     self.view.addSubview(cancelButton) 
     self.view.addSubview(validateButton) 

     validateButton.backgroundColor = UIColor.red 
     cancelButton.backgroundColor = UIColor.blue 

     validateButton.setTitle("V", for: UIControlState()) 
     cancelButton.setTitle("C", for: UIControlState()) 

     let leftCancel = NSLayoutConstraint(item: cancelButton, attribute: .leading, relatedBy: .equal, toItem: self.view, attribute: .leading, multiplier: 1, constant: 16) 
     let bottomCancel = NSLayoutConstraint(item: cancelButton, attribute: .bottom, relatedBy: .equal, toItem: self.view, attribute: .bottom, multiplier: 1, constant: -20) 
     let widthCancel = NSLayoutConstraint(item: cancelButton, attribute: .width, relatedBy: .equal, toItem: nil, attribute: .notAnAttribute, multiplier: 1, constant: 20) 
     let heightCancel = NSLayoutConstraint(item: cancelButton, attribute: .height, relatedBy: .equal, toItem: nil, attribute: .notAnAttribute, multiplier: 1, constant: 20) 
     let rightValidate = NSLayoutConstraint(item: validateButton, attribute: .trailing, relatedBy: .equal, toItem: self.view, attribute: .trailing, multiplier: 1, constant: -16) 
     let bottomValidate = NSLayoutConstraint(item: validateButton, attribute: .bottom, relatedBy: .equal, toItem: self.view, attribute: .bottom, multiplier: 1, constant: -20) 
     let widthValidate = NSLayoutConstraint(item: validateButton, attribute: .width, relatedBy: .equal, toItem: nil, attribute: .notAnAttribute, multiplier: 1, constant: 20) 
     let heightValidate = NSLayoutConstraint(item: validateButton, attribute: .height, relatedBy: .equal, toItem: nil, attribute: .notAnAttribute, multiplier: 1, constant: 20) 

     NSLayoutConstraint.activate([leftCancel, bottomCancel, rightValidate, bottomValidate, widthCancel, heightCancel, widthValidate, heightValidate]) 

     self.view.layoutIfNeeded() 
    } 

    func cancelAction() { 
     //  self.dismiss(animated: true, completion: nil) 
     print("cancel") 
    } 

    func validateAction() { 
     //  self.dismiss(animated: true, completion: nil) 
     print("validate") 
    } 
} 

var vc = MyController() 
vc.view.backgroundColor = UIColor.green 
vc.view.frame = CGRect(x: 0, y: 0, width: 400, height: 400) 

PlaygroundPage.current.liveView = vc.view 

PlaygroundPage.current.needsIndefiniteExecution = true 

あなたが/結果を確認するために遊び場のページにこれをコピー＆ペーストすることができるはずです。私はあなたのボタンイメージを持っていないので、私は "V"と "C"のタイトルを持っています。

重要な違いは、ボトムとトレーリングの値を負に設定することです。つまり、ボタンのボトムを（MINUS 20を含むビューの下に）設定します。同様に、Buttonの後端を含むビューの後端から-16になります。

Answer 2

これは複雑すぎるようです。 VisualFormat文字列で簡単にこれを実現できます。

はこちらをご覧https://developer.apple.com/library/content/documentation/UserExperience/Conceptual/AutolayoutPG/VisualFormatLanguage.html#//apple_ref/doc/uid/TP40010853-CH27-SW1

を持ってここにあなたのコードを使用した例です：

func addButtons() { 
    let cancelButton = UIButton(type: .custom) 
    let validateButton = UIButton(type: .custom) 

    cancelButton.setImage(UIImage(named: "cancel_icon"), for: .normal) 
    validateButton.setImage(UIImage(named: "validate_icon"), for: .normal) 

    cancelButton.addTarget(self, action: #selector(cancelAction), for: .touchUpInside) 
    validateButton.addTarget(self, action: #selector(validateAction), for: .touchUpInside) 

    cancelButton.translatesAutoresizingMaskIntoConstraints = false 
    validateButton.translatesAutoresizingMaskIntoConstraints = false 

    self.view.addSubview(cancelButton) 
    self.view.addSubview(validateButton) 

    // With visual format strings 
    let views = ["cancelButton" : cancelButton, "validateButton" : validateButton] 

    let horizontalFormat = "|[cancelButton]-[validateButton(==cancelButton)]|" 
    let verticalFormat = "V:[cancelButton]-10-|" 

    let horizontalConstraints = NSLayoutConstraint.constraints(withVisualFormat: horizontalFormat, options:.alignAllBottom , metrics: nil, views: views) 
    let verticalConstraints = NSLayoutConstraint.constraints(withVisualFormat: verticalFormat, options:.alignAllBottom, metrics: nil, views: views) 

    NSLayoutConstraint.activate(horizontalConstraints) 
    NSLayoutConstraint.activate(verticalConstraints) 

    self.view.layoutIfNeeded() 
}