scrollView InsideView Height

scrollViewHeight.swift

//
//  ViewController.swift
//  testProj
//
//  Created by LEE HAEUN on 09/10/2019.
//  Copyright © 2019 LEE HAEUN. All rights reserved.
//

import UIKit

class ViewController: UIViewController {
  
  var insideViewHeight: NSLayoutConstraint?
  
  override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view.
    initView()
  }
  
  func initView(){
    
    view.addSubview(mainView)
    mainView.addSubview(changeHeightBtn)
    mainView.addSubview(scrollView)
    scrollView.addSubview(insideView)
    // mainView가 화면에 딱 맞게 채워짐
    // scrollView는 mainView의 중앙에 있음
    NSLayoutConstraint.activate([
      mainView.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor),
      mainView.leadingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.leadingAnchor),
      mainView.trailingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.trailingAnchor),
      mainView.bottomAnchor.constraint(equalTo: view.safeAreaLayoutGuide.bottomAnchor),
      
      changeHeightBtn.topAnchor.constraint(equalTo: mainView.topAnchor),
      changeHeightBtn.widthAnchor.constraint(equalToConstant: 200),
      changeHeightBtn.heightAnchor.constraint(equalToConstant: 40),
      changeHeightBtn.centerXAnchor.constraint(equalTo: mainView.centerXAnchor),
      
      scrollView.topAnchor.constraint(equalTo: changeHeightBtn.bottomAnchor, constant: 10),
      scrollView.leadingAnchor.constraint(equalTo: mainView.leadingAnchor, constant: 10),
      scrollView.trailingAnchor.constraint(equalTo: mainView.trailingAnchor, constant: -10),
      scrollView.bottomAnchor.constraint(equalTo: mainView.bottomAnchor, constant: -10),
      
      insideView.topAnchor.constraint(equalTo: scrollView.topAnchor),
      insideView.leadingAnchor.constraint(equalTo: scrollView.leadingAnchor),
      insideView.widthAnchor.constraint(equalTo: scrollView.widthAnchor),
      insideView.bottomAnchor.constraint(equalTo: scrollView.bottomAnchor),
    ])
    insideViewHeight =       insideView.heightAnchor.constraint(equalToConstant: 100)
    insideViewHeight?.isActive = true
  }
  
  lazy var changeHeightBtn: UIButton = {
    let button = UIButton()
    button.backgroundColor = .blue
    button.translatesAutoresizingMaskIntoConstraints = false
    button.addTarget(nil, action: #selector(changeInsideViewHeight), for: .touchUpInside)
    button.setTitle("높이를 바꿉니다", for: .normal)
    return button
  }()
  lazy var mainView: UIView = {
    let view = UIView()
    view.translatesAutoresizingMaskIntoConstraints = false
    return view
  }()
  lazy var insideView: UIView = {
    let view = UIView()
    view.translatesAutoresizingMaskIntoConstraints = false
    view.backgroundColor = .yellow
    return view
  }()
  lazy var scrollView: UIScrollView = {
    let view = UIScrollView()
    view.translatesAutoresizingMaskIntoConstraints = false
    view.backgroundColor = .red
    return view
  }()
}


extension ViewController {
  @objc func changeInsideViewHeight() {
    if insideViewHeight?.constant == 100 {
      insideViewHeight?.constant = 1000
    }
    else {
      insideViewHeight?.constant = 100
    }
    insideViewHeight?.isActive = true

  }
}