範例：豆漿食譜

Objective

製作豆漿時，豆子與水的比例相當重要，此範例提供方便計算，而無需人為的換算

UI 

事實上，此 UI 僅提供簡單設計，重點在強調功能面。有關各 UI Component 日後再調整。

Code

//

//  ViewController.swift

//  FoodRecipeUnit

//

//  Created by Elvis Meng on 2017/5/8.

//  Copyright © 2017年 Elvis Meng. All rights reserved.

//

import UIKit

class ViewController: UIViewController, UIPickerViewDelegate, UIPickerViewDataSource {

    

    var soyBeanUnit =  ["公克","兩"]

    var waterUnit = ["瓢","升"]

    var sugarUnit = ["公克","兩"]

    var brixUnit = ["微甜","甜"]

    

    var soyBeanUnitSelected = "公克"

    var waterUnitSelected = "瓢"

    var sugarUnitSelected = "公克"

    var brixUnitSelected = "微甜"

    

    var soyBeanAmount = 0.0

    var waterAmount = 0.0

    var sugarAmount = 0.0

    

    @IBOutlet weak var soyBeanWeight: UITextField!

    @IBOutlet weak var waterWeight: UITextField!

    @IBOutlet weak var sugarWeight: UITextField!

    

    @IBAction func soyBeanEditOnExit(_ sender: UITextField) {

        

        if soyBeanUnitSelected == "兩" {

            soyBeanAmount = 600.0 * Double(soyBeanWeight.text!)!

        } else {

            soyBeanAmount = Double(soyBeanWeight.text!)!

        }

        

        if waterUnitSelected == "瓢" {

            waterWeight.text = String(soyBeanAmount * 7.0 / 1500.0)

        } else {

            waterWeight.text = String(soyBeanAmount * 7.0 * 2500 / 1500.0)

        }

        

    }

    

    @IBAction func waterEditOnExit(_ sender: UITextField) {

        

        if waterUnitSelected == "瓢"  {

            waterAmount = 2500.0 * Double(waterWeight.text!)!

        } else {

            waterAmount = Double(waterWeight.text!)!

        }

        

        if soyBeanUnitSelected == "兩" {

            soyBeanWeight.text = String(waterAmount * 2.5 / (7.0 * 2500.0))

            

        } else {

            soyBeanWeight.text = String(waterAmount * 2.5 / (7.0 * 2500.0) * 600.0)

        }

    }

    

    @IBAction func calcBtn(_ sender: UIButton) {

        soyBeanWeight.text = nil

        waterWeight.text = nil

        sugarWeight.text = nil

    }

    

    func numberOfComponents(in pickerView: UIPickerView) -> Int {

        return 1

    }

    

    func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {

        switch pickerView.tag {

        case 0:

            return soyBeanUnit.count

        case 1:

            return waterUnit.count

        case 2:

            return sugarUnit.count

        case 3:

            return brixUnit.count

        default:

            return 0

        }

    }

    

    func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {

        

        switch pickerView.tag {

        case 0:

            soyBeanUnitSelected = soyBeanUnit[row]

            return soyBeanUnit[row]

        case 1:

            waterUnitSelected = waterUnit[row]

            return waterUnit[row]

        case 2:

            sugarUnitSelected = sugarUnit[row]

            return sugarUnit[row]

        case 3:

            brixUnitSelected = brixUnit[row]

            return brixUnit[row]

        default:

            return "error"

        }

    }

    

    override func viewDidLoad() {

        super.viewDidLoad()

        // Do any additional setup after loading the view, typically from a nib.

        

    }

    override func didReceiveMemoryWarning() {

        super.didReceiveMemoryWarning()

        // Dispose of any resources that can be recreated.

    }

}

Test

Summary

1. 此範例不實作糖與甜度，此部分可留待日後實作
2. 在 textField 中，輸入資料，按下 enter，會啟動 EditingOnExit 事件，可自動帶出換算結果，而 UI 可省去 Calculate 這個 Button

Reference

1. UITextField, https://developer.apple.com/reference/uikit/uitextfield
2. UIViewController, https://developer.apple.com/reference/uikit/uiviewcontroller




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