CollapsibleTableSectionViewController/CollapsibleTableSectionViewController/CollapsibleTableViewHeader.swift at f6d16fc613205ce1038ee6c51057be3be3180627 · jeantimex/CollapsibleTableSectionViewController · GitHub

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//
//  CollapsibleTableViewHeader.swift
//  CollapsibleTableSectionViewController
//
//  Created by Yong Su on 7/20/17.
//  Copyright © 2017 jeantimex. All rights reserved.
//

import UIKit

protocol CollapsibleTableViewHeaderDelegate {
    func toggleSection(_ section: Int)
}

open class CollapsibleTableViewHeader: UITableViewHeaderFooterView {

    var delegate: CollapsibleTableViewHeaderDelegate?
    var section: Int = 0

    open var titleLabel = UILabel()
    open var arrowLabel = UILabel()

    private func initCommon() {
        // Content View
        contentView.backgroundColor = UIColor(hex: 0x2E3944)

        let marginGuide = contentView.layoutMarginsGuide

        // Arrow label
        contentView.addSubview(arrowLabel)
        arrowLabel.textColor = UIColor.white
        arrowLabel.translatesAutoresizingMaskIntoConstraints = false
        arrowLabel.widthAnchor.constraint(equalToConstant: 12).isActive = true
        arrowLabel.topAnchor.constraint(equalTo: marginGuide.topAnchor).isActive = true
        arrowLabel.trailingAnchor.constraint(equalTo: marginGuide.trailingAnchor).isActive = true
        arrowLabel.bottomAnchor.constraint(equalTo: marginGuide.bottomAnchor).isActive = true

        // Title label
        contentView.addSubview(titleLabel)
        titleLabel.textColor = UIColor.white
        titleLabel.translatesAutoresizingMaskIntoConstraints = false
        titleLabel.topAnchor.constraint(equalTo: marginGuide.topAnchor).isActive = true
        titleLabel.trailingAnchor.constraint(equalTo: marginGuide.trailingAnchor).isActive = true
        titleLabel.bottomAnchor.constraint(equalTo: marginGuide.bottomAnchor).isActive = true
        titleLabel.leadingAnchor.constraint(equalTo: marginGuide.leadingAnchor).isActive = true

        //
        // Call tapHeader when tapping on this header
        //
        addGestureRecognizer(UITapGestureRecognizer(target: self, action: #selector(CollapsibleTableViewHeader.tapHeader(_:))))
    }

    override public init(reuseIdentifier: String?) {
        super.init(reuseIdentifier: reuseIdentifier)
        initCommon()
    }

    required public init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        initCommon()
    }

    //
    // Trigger toggle section when tapping on the header
    //
    func tapHeader(_ gestureRecognizer: UITapGestureRecognizer) {
        guard let cell = gestureRecognizer.view as? CollapsibleTableViewHeader else {
            return
        }

        _ = delegate?.toggleSection(cell.section)
    }

    func setCollapsed(_ collapsed: Bool) {
        //
        // Animate the arrow rotation (see Extensions.swf)
        //
        arrowLabel.rotate(collapsed ? 0.0 : .pi / 2)
    }

}

extension UIColor {

    convenience init(hex:Int, alpha:CGFloat = 1.0) {
        self.init(
            red:   CGFloat((hex & 0xFF0000) >> 16) / 255.0,
            green: CGFloat((hex & 0x00FF00) >> 8)  / 255.0,
            blue:  CGFloat((hex & 0x0000FF) >> 0)  / 255.0,
            alpha: alpha
        )
    }

}

extension UIView {

    func rotate(_ toValue: CGFloat, duration: CFTimeInterval = 0.2) {
        let animation = CABasicAnimation(keyPath: "transform.rotation")

        animation.toValue = toValue
        animation.duration = duration
        animation.isRemovedOnCompletion = false
        animation.fillMode = kCAFillModeForwards

        self.layer.add(animation, forKey: nil)
    }

}