ViewController.swift

import UIKit

class ViewController: UIViewController {
    
    @IBOutlet weak var target1TextField: UITextField!
    @IBOutlet weak var target2TextField: UITextField!
    
    @IBOutlet weak var target1Label: UILabel!
    @IBOutlet weak var target2Label: UILabel!
    
    @IBOutlet weak var target1Switch: UISwitch!
    @IBOutlet weak var target2Switch: UISwitch!
    
    // 計算結果
    @IBOutlet weak var resultLabel: UILabel!

    @IBOutlet var tapGesture: UITapGestureRecognizer!

    override func viewDidLoad() {
        super.viewDidLoad()

        // ジェスチャー追加
        self.view.addGestureRecognizer(self.tapGesture)
    }

    // 計算処理
    @IBAction func calculate(sender: AnyObject) {
        
        let target1Num = (self.target1TextField.text as NSString).integerValue
        let target2Num = (self.target2TextField.text as NSString).integerValue
        
        let target1 = self.target1Switch.on ? -target1Num : target1Num
        let target2 = self.target2Switch.on ? -target2Num : target2Num
        
        self.target1Label.text = "\(target1)"
        self.target2Label.text = "\(target2)"
        self.resultLabel.text = "\(target1 + target2)"
    }
    
    // キーボード外をタップしてナンバーパッドを閉じる
    @IBAction func closeNumberPad(sender: UITapGestureRecognizer) {
        
        self.view.endEditing(true)
    }
    
    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }
}