[ 2022-08-17 🤖 TIL ]

😎 마크다운을 공부했으니 적용을 해보기로

import UIKit

class ViewController: UIViewController {
    let numOfTouchs = 2

    @IBOutlet var imgViewUp: UIImageView!
    @IBOutlet var imgViewLeft: UIImageView!
    @IBOutlet var imgViewRight: UIImageView!
    @IBOutlet var imgViewDown: UIImageView!
    
    var imgLeft = [UIImage]()
    var imgDown = [UIImage]()
    var imgUp = [UIImage]()
    var imgRight = [UIImage]()
    //아마자 배열에 추가

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view.
        
        imgUp.append(UIImage(named: "arrow-up-black.png")!)
        imgUp.append(UIImage(named: "arrow-up-red.png")!)
        imgUp.append(UIImage(named: "arrow-up-green.png")!)

        imgDown.append(UIImage(named: "arrow-down-black.png")!)
        imgDown.append(UIImage(named: "arrow-down-red.png")!)
        imgDown.append(UIImage(named: "arrow-down-green.png")!)

        imgLeft.append(UIImage(named: "arrow-left-black.png")!)
        imgLeft.append(UIImage(named: "arrow-left-red.png")!)
        imgLeft.append(UIImage(named: "arrow-left-green.png")!)
        
        imgRight.append(UIImage(named: "arrow-right-black.png")!)
        imgRight.append(UIImage(named: "arrow-right-red.png")!)
        imgRight.append(UIImage(named: "arrow-right-green.png")!)
        
        imgViewUp.image = imgUp[0]
        imgViewDown.image = imgDown[0]
        imgViewRight.image = imgRight[0]
        imgViewLeft.image = imgLeft[0]
        //처음 화면에 보여질 이미지를 뽑아와 화면에 보여줌
        
        let swipeUp = UISwipeGestureRecognizer(target: self, action: #selector(ViewController.respondToSwipeGesture(_:)))
        swipeUp.direction = UISwipeGestureRecognizer.Direction.up
        self.view.addGestureRecognizer(swipeUp)
        
        let swipeDown = UISwipeGestureRecognizer(target: self, action: #selector(ViewController.respondToSwipeGesture(_:)))
        swipeDown.direction = UISwipeGestureRecognizer.Direction.down
        self.view.addGestureRecognizer(swipeDown)
        
        let swipeRight = UISwipeGestureRecognizer(target: self, action: #selector(ViewController.respondToSwipeGesture(_:)))
        swipeRight.direction = UISwipeGestureRecognizer.Direction.right
        self.view.addGestureRecognizer(swipeRight)
        
        let swipeLeft = UISwipeGestureRecognizer(target: self, action: #selector(ViewController.respondToSwipeGesture(_:)))
        swipeLeft.direction = UISwipeGestureRecognizer.Direction.left
        self.view.addGestureRecognizer(swipeLeft)
        
        //화면에서 인식할 수 있는 제스쳐를 추가 합니다.(한손가락으로 위, 아래, 오른쪽, 왼쪽 스와이프)
        //스와이프 이벤트 발생시 선언해 놓은 respondToSwipeGesture 함수가 실행이 되도록 선언
        
        let swipeUpMulti = UISwipeGestureRecognizer(target: self, action: #selector(ViewController.respondToSwipeGestureMulti(_:)))
        swipeUpMulti.direction = UISwipeGestureRecognizer.Direction.up
        swipeUpMulti.numberOfTouchesRequired = numOfTouchs
        self.view.addGestureRecognizer(swipeUpMulti)
        
        let swipeDownMulti = UISwipeGestureRecognizer(target: self, action: #selector(ViewController.respondToSwipeGestureMulti(_:)))
        swipeDownMulti.direction = UISwipeGestureRecognizer.Direction.down
        swipeDownMulti.numberOfTouchesRequired = numOfTouchs
        self.view.addGestureRecognizer(swipeDownMulti)
        
        let swipeRightMulti = UISwipeGestureRecognizer(target: self, action: #selector(ViewController.respondToSwipeGestureMulti(_:)))
        swipeRightMulti.direction = UISwipeGestureRecognizer.Direction.right
        swipeRightMulti.numberOfTouchesRequired = numOfTouchs
        self.view.addGestureRecognizer(swipeRightMulti)
        
        let swipeLeftMulti = UISwipeGestureRecognizer(target: self, action: #selector(ViewController.respondToSwipeGestureMulti(_:)))
        swipeLeftMulti.direction = UISwipeGestureRecognizer.Direction.left
        swipeLeftMulti.numberOfTouchesRequired = numOfTouchs
        self.view.addGestureRecognizer(swipeLeftMulti)
        
        //화면 에서 인식할 수 있는 제스쳐를 추가 합니다.(두 손가락으로 위, 아래, 오른쪽, 왼쪽 스와이프)
        //스와이프 이벤트 발생시 선언해 놓은 respondToSwipeGestureMulti 함수가 실행이 되도록 선언
    }
    
    @objc func respondToSwipeGesture(_ gesture: UIGestureRecognizer){
        if let swipeGesture = gesture as? UISwipeGestureRecognizer {
            imgViewUp.image = imgUp[0]
            imgViewDown.image = imgDown[0]
            imgViewLeft.image = imgLeft[0]
            imgViewRight.image = imgRight[0]

            switch swipeGesture.direction {
                case UISwipeGestureRecognizer.Direction.up :
                    imgViewUp.image = imgUp[1]
                case UISwipeGestureRecognizer.Direction.down :
                    imgViewDown.image = imgDown[1]
                case UISwipeGestureRecognizer.Direction.right :
                    imgViewRight.image = imgRight[1]
                case UISwipeGestureRecognizer.Direction.left :
                    imgViewLeft.image = imgLeft[1]
                default :
                    break
            }}
        //제스쳐 이벤트 발생시 제스쳐 방향에 맞는 화살표이미지로 변경
    }
    
    @objc func respondToSwipeGestureMulti(_ gesture: UIGestureRecognizer){
        if let swipeGesture = gesture as? UISwipeGestureRecognizer {
            imgViewUp.image = imgUp[0]
            imgViewDown.image = imgDown[0]
            imgViewLeft.image = imgLeft[0]
            imgViewRight.image = imgRight[0]

            switch swipeGesture.direction {
                case UISwipeGestureRecognizer.Direction.up :
                    imgViewUp.image = imgUp[2]
                case UISwipeGestureRecognizer.Direction.down :
                    imgViewDown.image = imgDown[2]
                case UISwipeGestureRecognizer.Direction.right :
                    imgViewRight.image = imgRight[2]
                case UISwipeGestureRecognizer.Direction.left :
                    imgViewLeft.image = imgLeft[2]
                default :
                    break
            }}
        //제스쳐 이벤트 발생시 제스쳐 방향에 맞는 화살표이미지로 변경
    }
}

와..코드가 너무 이뻐졌다. 이걸 모르고 있었다니!

마크다운 관련 공부는 나중에 이어서 하고
일단 오늘은 swift를 이용하여 앱에 스와이프 이벤트 발생시
발생한 방향에 맞는 화살표 이미지를 변경하는 예제를 구현하였습니다.

UISwipeGestureRecognizer 클래스가 스와이프 이벤트의 방향을 인식하고 그에 맞는 함수를 실행시켜주는 일을 합니다.
swipeLeftMulti.numberOfTouchesRequired = numOfTouchs는 스와이프이벤트가 발생할 때 인식된 터치?의 갯수를 선언하는 구문입니다.

또한 오늘은 #selector에 대하여 궁금증이 생겨 따로 찾아보았습니다.

메서드를 식별하는 고유한 이름을 selector(셀렉터)라고 합니다.

위에 사용한 UISwipeGestureRecognizer 클래스에서 (target: Any?, action: Selector?) 파라미터로 셀렉터를 받을 때 선언 해주어 넘겨주면 됩니다.

셀랙터를 선언할 때에는 꼭 앞에 Objective-C에서도 사용할 수 있도록 하는@objc 를 붙여서 선언을 해야합니다.

도움:
https://velog.io/@kipsong/SwiftobjcUIKit-Seletor%EC%85%80%EB%A0%89%ED%84%B0%EC%97%90-%EB%8C%80%ED%95%98%EC%97%AC
https://woozzang.tistory.com/120