BMI 계산기 (화면 전환 및 데이터 전달)

 

 

일전에 배운 화면 전환과 데이터 전달을 통해 

간단한 BMI 계산기를 만듦

 

 

 

모든 UI는 코드로 작성

BMI 계산기는 간단한 로직으로 구성

사용자가 키와 몸무게를 입력 -> 계산 버튼 누름 ->

화면전환과 동시에 계산된 값을 전환된 화면에 보여줌

 

여기서 화면 전환, 데이터전달과 BMI 계산 관련된 함수는 각각 구현할 것 

1개의 함수는 1개의 기능만 하도록 할 것 

 

데이터를 전달할 때는 변수를 통해서 할 것 

 

 

 

BMI 계산식

 

 

 

BMI 계산 함수를 통해 반환된 bmi를 통해 

bmi 치수에 따른 글자 배경색과 문구를 설정 

 

 

 

DetailViewController에 데이터를 전달할 때 사용할 변수 

 

 

 

DetailVeiwController로 화면전환하면서 데이터 전달하는 함수 

 

 

 

ViewController에서 온 데이터를 DetailViewController에서 받기 위한 변수 

 

 

 

DetailViewController 파일에 결과값 표시 

 

 

 

ViewController.swift

import UIKit

class ViewController: UIViewController {
    
    var bmi: Double?
    var bmiBackgroundColor: UIColor?
    var bmiText: String?
    
    private let mainTitle: UILabel = {
        let label = UILabel()
        label.text = "BMI 계산기"
        label.font = .systemFont(ofSize: 35, weight: .bold)
        label.textColor = .label
        label.translatesAutoresizingMaskIntoConstraints = false
        return label
    }()
    
    private let heightLabel: UILabel = {
        let label = UILabel()
        label.text = "키"
        label.font = .systemFont(ofSize: 22, weight: .bold)
        label.translatesAutoresizingMaskIntoConstraints = false
        return label
    }()
    
    private let heightTextField: UITextField = {
        let textField = UITextField()
        textField.borderStyle = .bezel
        textField.font = .systemFont(ofSize: 22, weight: .regular)
        textField.translatesAutoresizingMaskIntoConstraints = false
        return textField
    }()
    
    private let weightLabel: UILabel = {
        let label = UILabel()
        label.text = "몸무게"
        label.font = .systemFont(ofSize: 22, weight: .bold)
        label.translatesAutoresizingMaskIntoConstraints = false
        return label
    }()
    
    private let weightTextField: UITextField = {
        let textField = UITextField()
        textField.borderStyle = .bezel
        textField.font = .systemFont(ofSize: 22, weight: .regular)
        textField.translatesAutoresizingMaskIntoConstraints = false
        return textField
    }()
    
    private lazy var calculateButton: UIButton = {
        let button = UIButton(type: UIButton.ButtonType.custom)
        button.translatesAutoresizingMaskIntoConstraints = false
        button.setTitle("계산", for: .normal)
        button.titleLabel?.font = UIFont.systemFont(ofSize: 20, weight: .bold)
        button.setTitleColor(.label, for: .normal)
        button.tintColor = .label
        button.layer.masksToBounds = true
        button.layer.cornerRadius = 5
        button.backgroundColor = .systemCyan
        
        button.addTarget(self, action: #selector(moveToDetailButtonTapped), for: .touchUpInside)
        return button
    }()
    
    @objc func moveToDetailButtonTapped() {
        let detailVC = DetailViewController()
        detailVC.modalPresentationStyle = .fullScreen
        
        guard let height = heightTextField.text,
              let weight = weightTextField.text else { return }
        
        bmi = calculateBMI(height: height, weight: weight)
        bmiBackgroundColor = getBackgroundColor()
        bmiText = getBMIAdviceString()
        
        detailVC.bmiResult = bmi
        detailVC.bmiBackground = bmiBackgroundColor
        detailVC.bmiTitleText = bmiText
        
        present(detailVC, animated: true)
    }
    
    
    func calculateBMI(height: String, weight: String) -> Double {
        guard let height = Double(height),
              let weight = Double(weight) else { return 0.0 }
        
        var bmi = weight / (height * height) * 10000
        bmi = round(bmi * 10) / 10
        print("BMI결과값: \(bmi)")
        return bmi
    }
    
    // 색깔 얻는 메서드
    func getBackgroundColor() -> UIColor {
        guard let bmi = bmi else { return UIColor.black }
        switch bmi {
        case ..<18.6:
            return UIColor.systemGreen
        case 18.6..<23.0:
            return UIColor.systemPurple
        case 23.0..<25.0:
            return UIColor.systemPink
        case 25.0..<30.0:
            return UIColor.systemOrange
        case 30.0...:
            return UIColor.systemRed
        default:
            return UIColor.black
        }
    }
    
    // 문자열 얻는 메서드
    func getBMIAdviceString() -> String {
        guard let bmi = bmi else { return "" }
        switch bmi {
        case ..<18.6:
            return "저체중"
        case 18.6..<23.0:
            return "표준"
        case 23.0..<25.0:
            return "과체중"
        case 25.0..<30.0:
            return "중도비만"
        case 30.0...:
            return "고도비만"
        default:
            return ""
        }
    }
    
    
    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view.
        view.backgroundColor = .systemBackground
        
        view.addSubview(mainTitle)
        view.addSubview(heightLabel)
        view.addSubview(heightTextField)
        view.addSubview(weightLabel)
        view.addSubview(weightTextField)
        view.addSubview(calculateButton)
   
        configureConstraints()
    }
    
    func configureConstraints() {
        
        let mainTitleConstraints = [
            mainTitle.centerXAnchor.constraint(equalTo: view.centerXAnchor),
            mainTitle.topAnchor.constraint(equalTo: view.topAnchor, constant: 150)
        ]
        
        let heightLabelConstraints = [
            heightLabel.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 40),
            heightLabel.topAnchor.constraint(equalTo: mainTitle.bottomAnchor, constant: 30)
        ]
        
        let heightTextFieldConstraints = [
            heightTextField.centerYAnchor.constraint(equalTo: heightLabel.centerYAnchor),
            heightTextField.leadingAnchor.constraint(equalTo: heightLabel.trailingAnchor, constant: 15),
            heightTextField.widthAnchor.constraint(equalToConstant: 300)
        ]
        
        let weightLabelConstraints = [
            weightLabel.trailingAnchor.constraint(equalTo: heightLabel.trailingAnchor),
            weightLabel.topAnchor.constraint(equalTo: heightLabel.bottomAnchor, constant: 20)
        ]
        
        let weightTextFieldConstraints = [
            weightTextField.leadingAnchor.constraint(equalTo: weightLabel.trailingAnchor, constant: 15),
            weightTextField.centerYAnchor.constraint(equalTo: weightLabel.centerYAnchor),
            weightTextField.widthAnchor.constraint(equalToConstant: 300)
        ]
        
        let calculateButtonConstraints = [
            calculateButton.leadingAnchor.constraint(equalTo: weightLabel.leadingAnchor),
            calculateButton.topAnchor.constraint(equalTo: weightLabel.bottomAnchor, constant: 20),
            calculateButton.trailingAnchor.constraint(equalTo: weightTextField.trailingAnchor)
        ]
        
        NSLayoutConstraint.activate(heightLabelConstraints)
        NSLayoutConstraint.activate(mainTitleConstraints)
        NSLayoutConstraint.activate(heightTextFieldConstraints)
        NSLayoutConstraint.activate(weightLabelConstraints)
        NSLayoutConstraint.activate(weightTextFieldConstraints)
        NSLayoutConstraint.activate(calculateButtonConstraints)
    }
}

 

 

 

DetailViewController.swift

import UIKit

class DetailViewController: UIViewController {
    
    var bmiResult: Double? = 0
    var bmiBackground: UIColor?
    var bmiTitleText: String?
    
    private let resultTitleLabel: UILabel = {
        let label = UILabel()
        label.translatesAutoresizingMaskIntoConstraints = false
        label.text = "결과"
        label.font = .systemFont(ofSize: 30, weight: .bold)
        return label
    }()
    
    private let bmiText: UILabel = {
        let label = UILabel()
        label.translatesAutoresizingMaskIntoConstraints = false
        label.text = "과체중"
        label.font = .systemFont(ofSize: 30, weight: .bold)
        label.textColor = .systemRed
        return label
    }()
    
    private let bmiLabel: UILabel = {
        let label = UILabel()
        label.translatesAutoresizingMaskIntoConstraints = false
        label.text = "BMI 결과값 표시"
        label.font = .systemFont(ofSize: 30, weight: .bold)
        label.textColor = .systemRed
        return label
    }()
    
    private let backToMainButton: UIButton = {
        let button = UIButton(type: .custom)
        button.translatesAutoresizingMaskIntoConstraints = false
        button.setTitle("Back", for: .normal)
        button.setTitleColor(.label, for: .normal)
        button.titleLabel?.font = .systemFont(ofSize: 22, weight: .bold)
        
        button.addTarget(self, action: #selector(backToMainButtonTapped), for: .touchUpInside)
        
        return button
    }()
    
    @objc func backToMainButtonTapped() {
        
        
        dismiss(animated: true)
    }

    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = .systemBackground
        
        
        
        bmiLabel.text = "\(bmiResult!)"
        bmiLabel.backgroundColor = bmiBackground
        bmiText.text = bmiTitleText
        
        view.addSubview(resultTitleLabel)
        view.addSubview(bmiLabel)
        view.addSubview(bmiText)
        view.addSubview(backToMainButton)
        configureConstraints()
    }
    
    func configureConstraints() {
        
        let backToMainButtonConstraints = [
            backToMainButton.centerXAnchor.constraint(equalTo: view.centerXAnchor),
            backToMainButton.bottomAnchor.constraint(equalTo: view.bottomAnchor, constant: -150)
        ]
        
        let resultTitleLabelConstraints = [
            resultTitleLabel.centerXAnchor.constraint(equalTo: view.centerXAnchor),
            resultTitleLabel.topAnchor.constraint(equalTo: view.topAnchor, constant: 200)
        ]
        
        let bmiTextConstraints = [
            bmiText.centerXAnchor.constraint(equalTo: view.centerXAnchor),
            bmiText.topAnchor.constraint(equalTo: bmiLabel.bottomAnchor, constant: 20)
        ]
        
        let bmiLabelConstraints = [
            bmiLabel.centerXAnchor.constraint(equalTo: view.centerXAnchor),
            bmiLabel.topAnchor.constraint(equalTo: resultTitleLabel.bottomAnchor, constant: 30)
        ]
        
        NSLayoutConstraint.activate(backToMainButtonConstraints)
        NSLayoutConstraint.activate(resultTitleLabelConstraints)
        NSLayoutConstraint.activate(bmiLabelConstraints)
        NSLayoutConstraint.activate(bmiTextConstraints)
    }

}