bar indicator add

MVMCoreUI/Atoms/Views/CarouselIndicator/IndicatorViews/BarsIndicatorView.swift

@@ -0,0 +1,141 @@
+//
+//  BarIndicatorView.swift
+//  MVMCoreUI
+//
+//  Created by Kevin Christiano on 2/3/20.
+//  Copyright © 2020 Verizon Wireless. All rights reserved.
+//
+
+import UIKit
+
+
+open class BarsIndicatorView: View, IndicatorViewProtocol {
+    //--------------------------------------------------
+    // MARK: - Properties
+    //--------------------------------------------------
+    
+    let stackView: StackView = {
+        let stackView = StackView()
+        stackView.axis = .horizontal
+        stackView.distribution = .equalSpacing
+        stackView.spacing = 6
+        return stackView
+    }()
+    
+    public var barsReference: [(view: View, constraint: NSLayoutConstraint)] = []
+    
+    // Dimensions are based on InVision Design Guidelines.
+    public static let indicatorBarWidth: CGFloat = 24
+    public static let indicatorBarHeight: (selected: CGFloat, unselected: CGFloat) = (selected: 4, unselected: 1)
+    
+    public var enabledColor: UIColor {
+        return (superview as? CarouselIndicator)?.indicatorTintColor ?? .black
+    }
+    
+    public var currentIndexColor: UIColor {
+        return (superview as? CarouselIndicator)?.currentIndicatorColor ?? .black
+    }
+    
+    public var disabledColor: UIColor {
+        return (superview as? CarouselIndicator)?.disabledIndicatorColor ?? .mvmCoolGray3
+    }
+    
+    /// Returns the numberOfPages count from its parent CarouselIndicator.
+    public var numberOfPages: Int? {
+        return (superview as? CarouselIndicator)?.numberOfPages
+    }
+    
+    /// Returns the numberOfPages count from its parent CarouselIndicator.
+    public var currentIndex: Int? {
+        return (superview as? CarouselIndicator)?.currentIndex
+    }
+    
+    open var isEnabled: Bool = true {
+        didSet {
+            barsReference.forEach { view, heightConstraint in
+                view.backgroundColor = isEnabled ? enabledColor : disabledColor
+            }
+        }
+    }
+    
+    //--------------------------------------------------
+    // MARK: - Initializers
+    //--------------------------------------------------
+    
+    public init() {
+        super.init(frame: .zero)
+    }
+    
+    public required init?(coder: NSCoder) {
+        fatalError("init(coder:) has not been implemented")
+    }
+    
+    //--------------------------------------------------
+    // MARK: - Setup
+    //--------------------------------------------------
+    
+    open override func setupView() {
+        super.setupView()
+        
+        guard subviews.isEmpty else { return }
+        
+        addSubview(stackView)
+        isUserInteractionEnabled = false
+        
+        stackView.centerXAnchor.constraint(equalTo: centerXAnchor).isActive = true
+        stackView.leadingAnchor.constraint(greaterThanOrEqualTo: leadingAnchor).isActive = true
+        trailingAnchor.constraint(lessThanOrEqualTo: stackView.trailingAnchor).isActive = true
+        
+        generateBars()
+    }
+    
+    //--------------------------------------------------
+    // MARK: - Methods
+    //--------------------------------------------------
+    
+    func generateBars() {
+        
+        guard let numberOfPages = numberOfPages,
+            let currentIndex = currentIndex
+            else { return }
+        
+        var bars = [(View, NSLayoutConstraint)]()
+        
+        for i in 0..<numberOfPages {
+            let bar = View()
+            bar.widthAnchor.constraint(equalToConstant: BarsIndicatorView.indicatorBarWidth).isActive = true
+            bar.backgroundColor = enabledColor
+            let barHeight = i == currentIndex ? BarsIndicatorView.indicatorBarHeight.selected : BarsIndicatorView.indicatorBarHeight.unselected
+            let heightConstraint = bar.heightAnchor.constraint(equalToConstant: barHeight)
+            heightConstraint.isActive = true
+            
+            stackView.addArrangedSubview(bar)
+            bars.append((bar, heightConstraint))
+        }
+        
+        barsReference = bars
+    }
+    
+    //--------------------------------------------------
+    // MARK: - IndicatorViewProtocol
+    //--------------------------------------------------
+    
+    public override func reset() {
+        super.reset()
+        barsReference.forEach { $0.view.removeFromSuperview() }
+        barsReference = []
+    }
+    
+    public func updateUI(previousIndex: Int, newIndex: Int, totalCount: Int, isAnimated: Bool) {
+        
+        let expression = {
+            self.barsReference[previousIndex].view.backgroundColor = self.enabledColor
+            self.barsReference[newIndex].view.backgroundColor = self.currentIndexColor
+            self.barsReference[previousIndex].constraint.constant = BarsIndicatorView.indicatorBarHeight.unselected
+            self.barsReference[newIndex].constraint.constant = BarsIndicatorView.indicatorBarHeight.selected
+            self.layoutIfNeeded()
+        }
+        
+        isAnimated ? UIView.animate(withDuration: 0.3) { expression() } : expression()
+    }
+}