APP解鎖畫面

performSegue, button(Tag), removeLast(), switch, alert

成品：大家都弄很可愛走點不同路線 ! 五条很帥但也幫推宿儺~

▲已學(體會)到 switch 美好，便直接捨棄 if else :P
▲以為小作業結果想很久還是不知怎做，無可奈何參考了學長.同學的…

前置作業

▲構思主題配置 Storyboard
▲加 View Controller，為仿真做首頁圖實際無作用(純粹ImageView)
▲每個數字按鈕的 Tag 填入和按鈕一樣數值(0~9) (圖一)
▲拉 Segue (圖二) ，設全螢幕 (圖三)，替 Segue 取名 (圖四)

圖一：數字按鈕 Tag 寫入 0~9

圖二：按右鍵拉Segue選擇Show，拉完會出現箭頭與頁面往下

圖三：將 presentation 從 Automatic 改為 Full Screen 顯示全螢幕

圖四：點選左邊 Segue 再將名稱寫入 Identifier

拉 IBOutlet

@IBOutlet weak var mainImage: UIImageView!
@IBOutlet weak var firstFingerImage: UIImageView!
@IBOutlet weak var secondFingerImage: UIImageView!
@IBOutlet weak var thirdFingerImage: UIImageView!
@IBOutlet weak var forthFingerImage: UIImageView!
@IBOutlet weak var ryomenTalkLabel: UILabel!
@IBOutlet weak var remindLabel: UILabel!

設置變數 / 常數 ：輸入密碼與正確密碼為字串

var count = 0
var enter = “”
let passcode = “9171”

拉 IBAction： 0~9 按鈕全拉至 enter Action，系統不接受名稱取作delete

@IBAction func enter(_ sender: UIButton) {
}
@IBAction func change(_ sender: UIButton) {
}

輸入密碼

▲每按一次數字按鈕 count +1，各顯示圖並填入密碼(意指第幾個密碼)
▲按哪一個數字會經 sender.tag 傳入 (先前 Tag 填的數字)
▲如輸入與密碼不符出現警告訊息且更換主圖及文字描述
▲按下警告訊息 okAction 後連動，換圖與文字外其餘恢復初始值
▲密碼相符時用以下程式切換頁面，無按鈕等可觸及狀況時很好用
➞ self.performSegue(withIdentifier: “homepageSegue”, sender:self)
➞ func performSegue(withIdentifier identifier: String, sender: Any?)

@IBAction func enter(_ sender: UIButton) {
   count += 1
   switch count {
   case 1:
       firstFingerImage.isHidden = false
       enter += “\(sender.tag)”
   case 2:
       secondFingerImage.isHidden = false
       enter += “\(sender.tag)”
   case 3:
       thirdFingerImage.isHidden = false
       enter += “\(sender.tag)”
   default:
       forthFingerImage.isHidden = false
       enter += “\(sender.tag)”
       if enter != passcode {
          mainImage.image = UIImage(named: “Ryomen2”)
          ryomenTalkLabel.text = “找死 ?”
          remindLabel.isHidden = true
       let controller = UIAlertController(title: “密碼錯誤”, message: 
           nil, preferredStyle: .alert)
       let okAction = UIAlertAction(title: “被識破啦? 我這就去拿真貨!”, 
           style: .default) {[self](_) in
           mainImage.image = UIImage(named: “Ryomen6”)
           ryomenTalkLabel.text = “鮮少有人如此,膽子不小嘛!”
           remindLabel.isHidden = false
           firstFingerImage.isHidden = true
           secondFingerImage.isHidden = true
           thirdFingerImage.isHidden = true
           forthFingerImage.isHidden = true
           count = 0
           enter = “”
       }
       controller.addAction(okAction)
       present(controller, animated: true, completion: nil)
       } else {
           self.performSegue(withIdentifier: “homepageSegue”, 
           sender:self)
       }
   }
}

刪除 / 更改密碼

▲每按一次 count -1 ，消失一個圖，刪除一個密碼(字串)
▲removeLast()可移除或回復物件的最後元素，String 可用但 Int 無法
➞@discardableResult mutating func removeLast() -> Self.Element
▲case 1 不直接寫 default 因怕按超過 4 次會出錯

@IBAction func change(_ sender: UIButton) {
    switch count {
    case 4:
         count -= 1
         forthFingerImage.isHidden = true
         enter.removeLast()
    case 3:
         count -= 1
         thirdFingerImage.isHidden = true
         enter.removeLast()
    case 2:
         count -= 1
         secondFingerImage.isHidden = true
         enter.removeLast()
    case 1:
         count -= 1
         firstFingerImage.isHidden = true
         enter.removeLast()
    default:
         break
    }
}

完整程式碼