SheetView

SheetView.swift

//
//  SheetView.swift
//  wrkts
//
//  Created by Alexey Pegov on 28.10.14.
//  Copyright (c) 2014 alexeypegov. All rights reserved.
//

import UIKit

class SheetView: UIView {
    
    enum ViewState: UInt {
        case Hidden = 1
        case Showing
        case Shown
        case Hiding
    }
    
    let kAnimationDuration = 0.3
    
    var state = ViewState.Hidden
    var constraint: NSLayoutConstraint?
    
    override init() {
        super.init()
        
        self.setTranslatesAutoresizingMaskIntoConstraints(false)

        self.backgroundColor = UIColor.fromHex(0xFFFFFF)
        
        self.layer.shadowOffset = CGSizeMake(0, 1)
        self.layer.shadowColor = UIColor.blackColor().CGColor
        self.layer.shadowRadius = 1.0
        self.layer.shadowOpacity = 0.6
    }
    
    override init(frame: CGRect) {
        super.init(frame: frame)
    }
    
    required init(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
    }
    
    func isVisible() -> Bool {
        return state != ViewState.Hidden
    }
    
    func setupConstraintsWithNavigatinBar(bar: UINavigationBar) {
        self.superview?.addConstraint(NSLayoutConstraint(item: self, attribute: NSLayoutAttribute.Left, relatedBy: NSLayoutRelation.Equal, toItem: bar, attribute: NSLayoutAttribute.Left, multiplier: 1.0, constant: 0))
        self.superview?.addConstraint(NSLayoutConstraint(item: self, attribute: NSLayoutAttribute.Right, relatedBy: NSLayoutRelation.Equal, toItem: bar, attribute: NSLayoutAttribute.Right, multiplier: 1.0, constant: 0))
        
//        self.superview?.addConstraint(NSLayoutConstraint(item: self, attribute: NSLayoutAttribute.Height, relatedBy: NSLayoutRelation.Equal, toItem: nil, attribute: NSLayoutAttribute.NotAnAttribute, multiplier: 1, constant: 100))
    }
    
    func constrainBehindNavigationBar(bar: UINavigationBar) {
        if (constraint != nil) {
            self.superview?.removeConstraint(constraint!)
        }
        
        constraint = NSLayoutConstraint(item: self, attribute: NSLayoutAttribute.Bottom, relatedBy: NSLayoutRelation.Equal, toItem: bar, attribute: NSLayoutAttribute.Bottom, multiplier: 1.0, constant: 0)
        
        self.superview?.addConstraint(constraint!)
    }
    
    func constrainBelowNavigationBar(bar: UINavigationBar) {
        if (constraint != nil) {
            self.superview?.removeConstraint(constraint!)
        }
        
        constraint = NSLayoutConstraint(item: self, attribute: NSLayoutAttribute.Top, relatedBy: NSLayoutRelation.Equal, toItem: bar, attribute: NSLayoutAttribute.Bottom, multiplier: 1.0, constant: 0)
        
        self.superview?.addConstraint(constraint!)
    }
    
    func showFromNavigationBar(bar: UINavigationBar, animated: Bool) {
        if (state == ViewState.Shown || state == ViewState.Showing) {
            self.hide(bar, animated: false)
        }
        
        bar.superview?.insertSubview(self, belowSubview: bar)
        self.setupConstraintsWithNavigatinBar(bar)
        
        if (animated && state == ViewState.Hidden) {
            self.constrainBehindNavigationBar(bar)
        }
        
        self.superview?.layoutIfNeeded()
        self.constrainBelowNavigationBar(bar);
        
        let animations = { () -> Void in
            self.state = ViewState.Showing
            self.superview?.layoutIfNeeded()
        }
        
        let completion = { (finished: Bool) -> Void in
            if (self.state == ViewState.Showing) {
                self.state = ViewState.Shown
            }
        }
        
        if (animated) {
            UIView.animateWithDuration(kAnimationDuration, delay: 0, usingSpringWithDamping: 0.5, initialSpringVelocity: 5, options: UIViewAnimationOptions.CurveEaseOut, animations: animations, completion: completion)
        } else {
            animations()
            completion(true)
        }
    }
    
    func hide(bar: UINavigationBar, animated: Bool) {
        if (state == ViewState.Hiding || state == ViewState.Hidden) {
            return
        }
        
        self.constrainBehindNavigationBar(bar)
        
        let animations = { () -> Void in
            self.state = ViewState.Hiding
            self.superview?.layoutIfNeeded()
        }
        
        let completion = { (finished: Bool) -> Void in
            self.state = ViewState.Hidden
            self.removeFromSuperview()
            self.state = ViewState.Hidden
        }
        
        if (animated) {
            UIView.animateWithDuration(kAnimationDuration, animations: animations, completion: completion)
        } else {
            animations()
            completion(true)
        }
    }

}