[Do it!] 스와이프 제스처 앱

Do it! 스위프트로 아이폰 앱 만들기
18장 스와이프 제스처 사용하기

📱 실행 화면 📱

---

💻 Step 1. 기본 환경 구성하기

• 빈 스토리보드에 Horizontal Stack View 배치하기
  • [Add New Constraints] 에서 왼쪽:16, 오른쪽:16 으로 설정하기
  • [Align] -> [Vertically in Container] = 0 으로 설정하기
• 세로 스택 뷰 안에 Image View, Vertical Stack View, Image View 배치하기
• 가로 스택 뷰 안에 Image View 2개 배치하기
  • 가로 스택 뷰를 선택하고 [Attributes inspector] -> [Distribution] -> [Fill Equally] 선택하기
• 모든 이미지 뷰를 선택하고 [Add New Constraints] -> [Height] = 72 로 설정하기

각 이미지 뷰에 이미지 설정하기

💻 Step 2. Outlet 변수 추가하기

💻 Step 3. 한 손가락 스와이프 기능 구현하기

import UIKit

class ViewController: UIViewController {
    @IBOutlet var imgViewUp: UIImageView!
    @IBOutlet var imgViewLeft: UIImageView!
    @IBOutlet var imgViewRight: UIImageView!
    @IBOutlet var imgViewDown: UIImageView!
    
    var imgUp = [UIImage]()
    var imgDown = [UIImage]()
    var imgLeft = [UIImage]()
    var imgRight = [UIImage]()

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view.
        
        imgUp.append(UIImage(named: "./images/arrow-up-black.png")!)
        imgUp.append(UIImage(named: "./images/arrow-up-red.png")!)
        imgDown.append(UIImage(named: "./images/arrow-down-black.png")!)
        imgDown.append(UIImage(named: "./images/arrow-down-red.png")!)
        imgLeft.append(UIImage(named: "./images/arrow-left-black.png")!)
        imgLeft.append(UIImage(named: "./images/arrow-left-red.png")!)
        imgRight.append(UIImage(named: "./images/arrow-right-black.png")!)
        imgRight.append(UIImage(named: "./images/arrow-right-red.png")!)

        imgViewUp.image = imgUp[0]
        imgViewDown.image = imgDown[0]
        imgViewLeft.image = imgLeft[0]
        imgViewRight.image = imgRight[0]

• 이미지 배열 선언하기
• 이미지 배열에 이미지 할당하기
• 이미지 뷰에 이미지 할당하기

    override func viewDidLoad() {
        super.viewDidLoad()
        ...
        
        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 swipeLeft = UISwipeGestureRecognizer(target: self, action: #selector(ViewController.respondToSwipeGesture(_:)))
        swipeLeft.direction = UISwipeGestureRecognizer.Direction.left
        self.view.addGestureRecognizer(swipeLeft)
        
        let swipeRight = UISwipeGestureRecognizer(target: self, action: #selector(ViewController.respondToSwipeGesture(_:)))
        swipeRight.direction = UISwipeGestureRecognizer.Direction.right
        self.view.addGestureRecognizer(swipeRight)
    }
    
    @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.left:
                imgViewLeft.image = imgLeft[1]
            case UISwipeGestureRecognizer.Direction.right:
                imgViewRight.image = imgRight[1]
            default:
                break
            }
        }
    }
}

• 스와이프 제스처 등록하기
• 스와이프 제스처에 대한 액션 메소드 구현하기

💻 Step 4. 멀티 터치 스와이프 제스처 인식하기

    let numOfTouches = 2

    override func viewDidLoad() {
        super.viewDidLoad()
        ...
        
        let swipeUp = UISwipeGestureRecognizer(target: self, action: #selector(ViewController.respondToSwipeGesture(_:)))
        swipeUp.direction = UISwipeGestureRecognizer.Direction.up
        swipeUp.numberOfTouchesRequired = numOfTouches
        self.view.addGestureRecognizer(swipeUp)
        
        let swipeDown = UISwipeGestureRecognizer(target: self, action: #selector(ViewController.respondToSwipeGesture(_:)))
        swipeDown.direction = UISwipeGestureRecognizer.Direction.down
        swipeDown.numberOfTouchesRequired = numOfTouches
        self.view.addGestureRecognizer(swipeDown)
        
        let swipeLeft = UISwipeGestureRecognizer(target: self, action: #selector(ViewController.respondToSwipeGesture(_:)))
        swipeLeft.direction = UISwipeGestureRecognizer.Direction.left
        swipeLeft.numberOfTouchesRequired = numOfTouches
        self.view.addGestureRecognizer(swipeLeft)
        
        let swipeRight = UISwipeGestureRecognizer(target: self, action: #selector(ViewController.respondToSwipeGesture(_:)))
        swipeRight.direction = UISwipeGestureRecognizer.Direction.right
        swipeRight.numberOfTouchesRequired = numOfTouches
        self.view.addGestureRecognizer(swipeRight)
    }

• 상수 선언하기
• 스와이프 인식에 필요한 터치 개수 설정하기

💻 Step 5. 다중 스와이프 제스처 인식하기

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

이미지 배열에 이미지 추가하기

        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 swipeLeft = UISwipeGestureRecognizer(target: self, action: #selector(ViewController.respondToSwipeGesture(_:)))
        swipeLeft.direction = UISwipeGestureRecognizer.Direction.left
        self.view.addGestureRecognizer(swipeLeft)
        
        let swipeRight = UISwipeGestureRecognizer(target: self, action: #selector(ViewController.respondToSwipeGesture(_:)))
        swipeRight.direction = UISwipeGestureRecognizer.Direction.right
        self.view.addGestureRecognizer(swipeRight)
        
        let swipeUpMulti = UISwipeGestureRecognizer(target: self, action: #selector(ViewController.respondToSwipeGestureMulti(_:)))
        swipeUpMulti.direction = UISwipeGestureRecognizer.Direction.up
        swipeUpMulti.numberOfTouchesRequired = numOfTouches
        self.view.addGestureRecognizer(swipeUpMulti)
        
        let swipeDownMulti = UISwipeGestureRecognizer(target: self, action: #selector(ViewController.respondToSwipeGestureMulti(_:)))
        swipeDownMulti.direction = UISwipeGestureRecognizer.Direction.down
        swipeDownMulti.numberOfTouchesRequired = numOfTouches
        self.view.addGestureRecognizer(swipeDownMulti)
        
        let swipeLeftMulti = UISwipeGestureRecognizer(target: self, action: #selector(ViewController.respondToSwipeGestureMulti(_:)))
        swipeLeftMulti.direction = UISwipeGestureRecognizer.Direction.left
        swipeLeftMulti.numberOfTouchesRequired = numOfTouches
        self.view.addGestureRecognizer(swipeLeftMulti)
        
        let swipeRightMulti = UISwipeGestureRecognizer(target: self, action: #selector(ViewController.respondToSwipeGestureMulti(_:)))
        swipeRightMulti.direction = UISwipeGestureRecognizer.Direction.right
        swipeRightMulti.numberOfTouchesRequired = numOfTouches
        self.view.addGestureRecognizer(swipeRightMulti)
    }

    @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.left:
                imgViewLeft.image = imgLeft[2]
            case UISwipeGestureRecognizer.Direction.right:
                imgViewRight.image = imgRight[2]
            default:
                break;
            }
        }
    }
}

• 기존 스와이프 제스처의 numberOfTouchesRequired 코드 삭제하기
• 다중 스와이프 제스처 등록하기
  • numberOfTouchesRequired 설정하기
• 다중 스와이프 제스처에 대한 액션 메소드 구현하기

💻 Final Step. 전체 소스 코드

import UIKit

class ViewController: UIViewController {
    @IBOutlet var imgViewUp: UIImageView!
    @IBOutlet var imgViewLeft: UIImageView!
    @IBOutlet var imgViewRight: UIImageView!
    @IBOutlet var imgViewDown: UIImageView!
    
    var imgUp = [UIImage]()
    var imgDown = [UIImage]()
    var imgLeft = [UIImage]()
    var imgRight = [UIImage]()
    
    let numOfTouches = 2

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

        imgViewUp.image = imgUp[0]
        imgViewDown.image = imgDown[0]
        imgViewLeft.image = imgLeft[0]
        imgViewRight.image = imgRight[0]
        
        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 swipeLeft = UISwipeGestureRecognizer(target: self, action: #selector(ViewController.respondToSwipeGesture(_:)))
        swipeLeft.direction = UISwipeGestureRecognizer.Direction.left
        self.view.addGestureRecognizer(swipeLeft)
        
        let swipeRight = UISwipeGestureRecognizer(target: self, action: #selector(ViewController.respondToSwipeGesture(_:)))
        swipeRight.direction = UISwipeGestureRecognizer.Direction.right
        self.view.addGestureRecognizer(swipeRight)
        
        let swipeUpMulti = UISwipeGestureRecognizer(target: self, action: #selector(ViewController.respondToSwipeGestureMulti(_:)))
        swipeUpMulti.direction = UISwipeGestureRecognizer.Direction.up
        swipeUpMulti.numberOfTouchesRequired = numOfTouches
        self.view.addGestureRecognizer(swipeUpMulti)
        
        let swipeDownMulti = UISwipeGestureRecognizer(target: self, action: #selector(ViewController.respondToSwipeGestureMulti(_:)))
        swipeDownMulti.direction = UISwipeGestureRecognizer.Direction.down
        swipeDownMulti.numberOfTouchesRequired = numOfTouches
        self.view.addGestureRecognizer(swipeDownMulti)
        
        let swipeLeftMulti = UISwipeGestureRecognizer(target: self, action: #selector(ViewController.respondToSwipeGestureMulti(_:)))
        swipeLeftMulti.direction = UISwipeGestureRecognizer.Direction.left
        swipeLeftMulti.numberOfTouchesRequired = numOfTouches
        self.view.addGestureRecognizer(swipeLeftMulti)
        
        let swipeRightMulti = UISwipeGestureRecognizer(target: self, action: #selector(ViewController.respondToSwipeGestureMulti(_:)))
        swipeRightMulti.direction = UISwipeGestureRecognizer.Direction.right
        swipeRightMulti.numberOfTouchesRequired = numOfTouches
        self.view.addGestureRecognizer(swipeRightMulti)
    }
    
    @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.left:
                imgViewLeft.image = imgLeft[1]
            case UISwipeGestureRecognizer.Direction.right:
                imgViewRight.image = imgRight[1]
            default:
                break
            }
        }
    }
    @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.left:
                imgViewLeft.image = imgLeft[2]
            case UISwipeGestureRecognizer.Direction.right:
                imgViewRight.image = imgRight[2]
            default:
                break;
            }
        }
    }
}

---

💻 도전! Mission 갤러리 앱에 스와이프 기능 추가하기

import UIKit

var images = ["01", "02", "03", "04", "05", "06"]

class ViewController: UIViewController {
    @IBOutlet var imgView: UIImageView!
    @IBOutlet var pageControl: UIPageControl!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view.
        
        pageControl.numberOfPages = images.count
        pageControl.currentPage = 0
        pageControl.pageIndicatorTintColor = UIColor.lightGray
        pageControl.currentPageIndicatorTintColor = UIColor.darkGray
        imgView.image = UIImage(named: images[0])
        
        let swipeLeft = UISwipeGestureRecognizer(target: self, action: #selector(ViewController.respondToSwipeGesture(_:)))
        swipeLeft.direction = UISwipeGestureRecognizer.Direction.left
        self.view.addGestureRecognizer(swipeLeft)
        
        let swipeRight = UISwipeGestureRecognizer(target: self, action: #selector(ViewController.respondToSwipeGesture(_:)))
        swipeRight.direction = UISwipeGestureRecognizer.Direction.right
        self.view.addGestureRecognizer(swipeRight)
    }
    
    @IBAction func pageChange(_ sender: UIPageControl) {
        imgView.image = UIImage(named: images[pageControl.currentPage])
    }
    @objc func respondToSwipeGesture(_ gesture: UIGestureRecognizer) {
        if let swipeGesture = gesture as? UISwipeGestureRecognizer {
            switch swipeGesture.direction {
            case UISwipeGestureRecognizer.Direction.left:
                pageControl.currentPage += 1
                pageChange(pageControl)
            case UISwipeGestureRecognizer.Direction.right:
                pageControl.currentPage -= 1
                pageChange(pageControl)
            default:
                break
            }
        }
    }
    
}