swift5メモ

コードから直接セーフアリアにconstraintする

+読み込んだwebページのURLをprint

swift5

import UIKit
import WebKit

class ViewController: UIViewController, WKNavigationDelegate {

    override func viewDidLoad() {
        super.viewDidLoad()

        let webView = WKWebView(frame: .zero)
        webView.translatesAutoresizingMaskIntoConstraints = false
        webView.navigationDelegate = self
        view.addSubview(webView)

        webView.leftAnchor.constraint(equalTo: view.safeLeftAnchor).isActive = true
        webView.rightAnchor.constraint(equalTo: view.safeRightAnchor).isActive = true
        webView.topAnchor.constraint(equalTo: view.safeTopAnchor, constant: 60).isActive = true
        webView.bottomAnchor.constraint(equalTo: view.safeBottomAnchor, constant: 100).isActive = true
    }

    // 読み込んだwebページのURLをprint
    func webView(_ webView: WKWebView, didFinish navigation: WKNavigation!) {
        let activeUrl: URL? = self.webView.url
        let url = activeUrl?.absoluteString
        print(url)
    } 
}

extension UIView {
    var safeTopAnchor: NSLayoutYAxisAnchor {
        if #available(iOS 11.0, *) {
            return self.safeAreaLayoutGuide.topAnchor
        }
        return self.topAnchor
    }

    var safeLeftAnchor: NSLayoutXAxisAnchor {
        if #available(iOS 11.0, *){
            return self.safeAreaLayoutGuide.leftAnchor
        }
        return self.leftAnchor
    }

    var safeRightAnchor: NSLayoutXAxisAnchor {
        if #available(iOS 11.0, *){
            return self.safeAreaLayoutGuide.rightAnchor
        }
        return self.rightAnchor
    }

    var safeBottomAnchor: NSLayoutYAxisAnchor {
        if #available(iOS 11.0, *) {
            return self.safeAreaLayoutGuide.bottomAnchor
        }
        return self.bottomAnchor
    }
}

配列を値から検索して削除

削除したい値以外で新しい配列を作成

swift5

        var array = ["a","b","c","d","e","f"]
        array = array.filter { $0 != "d" }
        print(array)    //結果:["a", "b", "c", "e", "f"]

配列で値が重複してなかったら追加

swift5

        var array = ["a","b","c","d","e","f"]
        let target = "s"
        if !array.contains(target) {
            array.append(target)    //重複してなかったら追加される
        }
        print(array)    //["a", "b", "c", "d", "e", "f", "s"]

switch文の挙動

default: break or returnの違い
breakはswitch文からの離脱
returnは関数からの離脱

swift5

import UIKit

class ViewController: UIViewController {

    @IBOutlet weak var textFieldA: UITextField!
    @IBOutlet weak var textFieldB: UITextField!
    @IBOutlet weak var textFieldC: UITextField!

    override func viewDidLoad() {
        super.viewDidLoad()
    }

    func textFieldDidEndEditing(_ textField: UITextField) {
        switch textField {
        case textFieldA:
            textFieldA.text = "AAA"
        case textFieldB:
            textFieldB.text = String(987)
        default:
            break   // or return
        }
        print(textField.text!)
        // textFieldA,textFieldBを編集した時は必ず実行されるがtextFieldCの時、breakなら実行される
        // returnならtextFieldDidEndEditing()から抜けてしまうので実行されない
    }

}