［Swift/iOS］StoryBoardを使わずに、UIButtonを実装する方法

開発環境

Swift 4
Xcode 9.2

ポイント

UIButtonの追加

sample.swift

let button:UIButton = UIButton(frame: CGRect(x: 0, y: 50, width: self.view.frame.width, height: self.view.frame.height / 4))
button.backgroundColor = .black
button.setTitle("sample", for: .normal)
button.setTitleColor(.white, for: .normal)
self.view.addSubview(button)

UIButtonを押すと、発火するfunc

func の前に @objc を追加

sample.swift

@objc func pushButton(sender: UIButton){
        print("button pushed.")
}

UIButtonとfuncの紐付け

sample.swift

let button:UIButton = UIButton(frame: CGRect(x: 0, y: 50, width: self.view.frame.width, height: self.view.frame.height / 4))
button.backgroundColor = .black
button.setTitle("sample", for: .normal)
button.setTitleColor(.white, for: .normal)

//追加したコード
button.addTarget(self, action: #selector(pushButton), for: .touchUpInside)

self.view.addSubview(button)

コード例

ViewController.swift

import UIKit

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        
        let button:UIButton = UIButton(frame: CGRect(x: 0, y: 50, width: self.view.frame.width, height: self.view.frame.height / 4))
        button.backgroundColor = .black
        button.setTitle("sample", for: .normal)
        button.setTitleColor(.white, for: .normal)
        button.addTarget(self, action: #selector(pushButton), for: .touchUpInside)
        self.view.addSubview(button)
        
    }
    
    @objc func pushButton(sender: UIButton){
        print("button pushed.")
    }

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

}