CustomAccessoryToolbar.swift

import UIKit

protocol CustomAccessoryToolbarDelegate {
    var userEnabledFields: [UIView]! {get set}
    func previousButtonClicked(_ sender: UIView)
    func nextButtonClicked(_ sender: UIView)
    func doneButtonClicked(_ sender: UIView)
}

extension CustomAccessoryToolbarDelegate where Self: UIViewController {
    
    func previousButtonClicked(_ sender: UIView) {
        if let index = self.userEnabledFields?.index(of: sender), index - 1 >= 0 {
            let nextView = self.userEnabledFields[index - 1]
            nextView.becomeFirstResponder()
            
            
        } else {
            self.view.endEditing(true)
        }
    }
    
    func nextButtonClicked(_ sender: UIView) {
        if let index = self.userEnabledFields?.index(of: sender), index + 1 < self.userEnabledFields.count {
            let nextView = self.userEnabledFields[index + 1]
            nextView.becomeFirstResponder()
            
            
        } else {
            self.view.endEditing(true)
        }
    }
    
    func doneButtonClicked(_ sender: UIView) {
        self.view.endEditing(true)
    }
}

class CustomAccessoryToolbar: UIToolbar {
    
    var toolbarDelegate: CustomAccessoryToolbarDelegate?
    var currentlySelectedTextboxIndex: UIView!
    
    convenience init(delegate: CustomAccessoryToolbarDelegate) {
        self.init()
        self.toolbarDelegate = delegate
        NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow), name: NSNotification.Name.UITextFieldTextDidBeginEditing, object: nil)
        
        NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow), name: NSNotification.Name.UITextViewTextDidBeginEditing, object: nil)
        
        NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillHide), name: NSNotification.Name.UITextViewTextDidEndEditing, object: nil)
        
        NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillHide), name: NSNotification.Name.UIKeyboardWillHide, object: nil)
        
        configureToolbar()
    }
    
    override init(frame: CGRect) {
        super.init(frame: frame)
    }
    
    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
    }
    
    func keyboardWillShow(_ sender: Notification) {
        if let userInfo = sender.object as? UITextField {
            self.currentlySelectedTextboxIndex = userInfo
        }
        if let userInfo = sender.object as? UITextView {
            self.currentlySelectedTextboxIndex = userInfo
        }
    }

    func keyboardWillHide(_ sender: Notification) {
        NotificationCenter.default.removeObserver(self, name:NSNotification.Name.UITextFieldTextDidBeginEditing, object: nil)
        NotificationCenter.default.removeObserver(self, name:NSNotification.Name.UITextViewTextDidBeginEditing, object: nil)
        
        NotificationCenter.default.removeObserver(self, name:NSNotification.Name.UIKeyboardWillHide, object: nil)
        
    }
    
    func configureToolbar() {
        
        self.barStyle = UIBarStyle.black
        self.tintColor = UIColor.applicationYellowColor()
        self.isTranslucent = true
        self.sizeToFit()
        let barSegment = self.getNextPrevButtons()
        let doneButton = self.getDoneButton()
        
        let flexibleSpace = UIBarButtonItem(barButtonSystemItem: .flexibleSpace, target: nil, action: nil)
        
        self.setItems([barSegment, flexibleSpace, doneButton], animated: true)
        
    }
    
    fileprivate func getNextPrevButtons() -> UIBarButtonItem {
        let segmentControl = UISegmentedControl(items: ["Previous", "Next"])
        segmentControl.addTarget(self, action: #selector(segmentClicked(_:)), for: .valueChanged)
        segmentControl.isMomentary = true
        return UIBarButtonItem(customView: segmentControl)
    }
    
    fileprivate func getDoneButton() -> UIBarButtonItem {
        return UIBarButtonItem(barButtonSystemItem: .done, target: self, action: #selector(userClickedDone(_:)))
    }
    
    func userClickedDone(_ sender: AnyObject?) {
        self.toolbarDelegate?.doneButtonClicked(self.currentlySelectedTextboxIndex)
    }
    
    func segmentClicked(_ sender: AnyObject?) {
        _ = sender?.resignFirstResponder()
        if let selectedIndex = sender?.selectedSegmentIndex {
            
            switch selectedIndex {
            case 0:
                self.toolbarDelegate?.previousButtonClicked(self.currentlySelectedTextboxIndex)
                break
            case 1:
                self.toolbarDelegate?.nextButtonClicked(self.currentlySelectedTextboxIndex)
                break
                
            default: break
            }
        }
    }
}