SteviaLayout Animation

ViewController.swift

//
//  ViewController.swift
//  steviademo
//
//  Created by Onur Geneş on 17.07.2018.
//  Copyright © 2018 Onur Geneş. All rights reserved.
//

import UIKit
import Stevia

class ViewController: UIViewController, UITextFieldDelegate {

    lazy var topView: UIView = {
        let v = UIView()
        v.backgroundColor = .red
        return v
    }()
    
    lazy var bottomView: UIView = {
        let v = UIView()
        v.backgroundColor = .blue
        return v
    }()
    
    lazy var collectionView: UIView = {
        let v = UIView()
        v.backgroundColor = .green
        return v
    }()
    
    lazy var addButtonView: UIView = {
        let v = UIView()
        v.backgroundColor = .yellow
        v.addGestureRecognizer(UITapGestureRecognizer(target: self, action: #selector(handleKeyboard)))
        v.isUserInteractionEnabled = true
        return v
    }()
    
    @objc func handleKeyboard() {
        
        self.view.layout(
            |-0-self.bottomView.height(50)-0-|,
            150,
            |-0-self.collectionView.height(50)-0-|,
            0
        )
        
        self.view.setNeedsLayout()
        
        UIView.animate(withDuration: 0.5) {
            self.view.layoutIfNeeded()
        }
    }
    
    lazy var sendButtonView: UIView = {
        let v = UIView()
        v.backgroundColor = .yellow
        v.addGestureRecognizer(UITapGestureRecognizer(target: self, action: #selector(handleKeyboardDismiss)))
        v.isUserInteractionEnabled = true
        return v
    }()
    
    @objc func handleKeyboardDismiss() {
        
        view.setNeedsLayout()
        
        self.view.layout(
            |-0-self.bottomView.height(50)-0-|,
            0,
            |-0-self.collectionView.height(50)-0-|,
            0
        )
        
        UIView.animate(withDuration: 0.5) {
            self.view.layoutIfNeeded()
        }
    }
    
    lazy var textField: UITextField = {
        let tf = UITextField()
        tf.borderStyle = .roundedRect
        tf.layer.cornerRadius = 20
        tf.layer.masksToBounds = true
        tf.returnKeyType = .done
        return tf
    }()
    
    lazy var backgroundView: UIView = {
        let v = UIView()
        v.backgroundColor = .brown
        return v
    }()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        view.backgroundColor = .white
        
        textField.delegate = self
        
        view.sv(
            backgroundView,
            topView,
            bottomView.sv(
                addButtonView,
                textField,
                sendButtonView
            ),
            collectionView
        )
        
        view.layout(
            0,
            |-0-backgroundView-0-|,
            0
        )
        
        view.layout(
            0,
            |-0-topView.height(100)-0-|
        )
        
        view.layout(
            |-0-bottomView.height(50)-0-|,
            0,
            |-0-collectionView.height(50)-0-|,
            0
        )
        
        bottomView.layout(
            5,
            |-5-addButtonView.width(40)-5-textField-5-sendButtonView.width(40).heightEqualsWidth()-5-|,
            5
        )
        
        NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShowAnimation), name: NSNotification.Name.UIKeyboardWillShow, object: nil)
        NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillHideAnimation), name: NSNotification.Name.UIKeyboardWillHide, object: nil)
    }
    
    @objc func keyboardWillShowAnimation(notification: Notification) {
        guard let keyboardRect = (notification.userInfo![UIKeyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue else  { return }
        
        if notification.name == NSNotification.Name.UIKeyboardWillShow {
            self.view.setNeedsLayout()
            
            self.view.layout(
                |-0-self.bottomView.height(50)-0-|,
                keyboardRect.height,
                |-0-self.collectionView.height(50)-0-|,
                0
            )
            
            UIView.animate(withDuration: 0.5) {
                self.view.layoutIfNeeded()
            }
        }
    }
    
    @objc func keyboardWillHideAnimation(notification: Notification) {
        //guard let keyboardRect = (notification.userInfo![UIKeyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue else  { return }
        if notification.name == NSNotification.Name.UIKeyboardWillHide {
            
            UIView.animate(withDuration: 0.5) {
                
                self.view.layout(
                    |-0-self.bottomView.height(50)-0-|,
                    0,
                    |-0-self.collectionView.height(50)-0-|,
                    0
                )
                
                self.view.layoutIfNeeded()
            }
        }
    }
    
    func textFieldShouldReturn(_ textField: UITextField) -> Bool {
        view.endEditing(true)
        return true
    }
}