KeyboardListener

KeyboardListener

//
//  KeyboardListener.swift
//  KeyboardListener
//
//  Created by Jānis Kiršteins on 15/03/15.
//  Copyright (c) 2015 Jānis Kiršteins. All rights reserved.
//

import UIKit

public struct KeyboardNotificationInfo: Printable {
    public let beginFrame: CGRect
    public let endFrame: CGRect
    public let animationDuration: NSTimeInterval
    public let animationCurveRawValue: Int
    
    public var description: String {
        return toString([
            "beginFrame" : toString(self.beginFrame),
            "endFrame" : toString(self.endFrame),
            "animationDuration" : self.animationDuration,
            "animationCurveRawValue" : self.animationCurveRawValue
            ])
    }
    
    private init(notification: NSNotification) {
        let userInfo = notification.userInfo as! [String : AnyObject]
        
        self.animationCurveRawValue = userInfo[UIKeyboardAnimationCurveUserInfoKey] as! NSNumber as Int
        self.animationDuration = userInfo[UIKeyboardAnimationDurationUserInfoKey] as! NSNumber as NSTimeInterval
        
        let beginFrameValue = userInfo[UIKeyboardFrameBeginUserInfoKey] as! NSValue
        self.beginFrame = beginFrameValue.CGRectValue()
        
        let endFrameValue = userInfo[UIKeyboardFrameEndUserInfoKey] as! NSValue
        self.endFrame = endFrameValue.CGRectValue()
    }
}

public class KeyboardListener: NSObject {
    public var onWillShow: ((info: KeyboardNotificationInfo) -> ())?
    public var onWillHide: ((info: KeyboardNotificationInfo) -> ())?
    public var onDidShow: ((info: KeyboardNotificationInfo) -> ())?
    public var onDidHide: ((info: KeyboardNotificationInfo) -> ())?
    public var onFrameWillChange: ((info: KeyboardNotificationInfo) -> ())?
    public var onFrameDidChange: ((info: KeyboardNotificationInfo) -> ())?
    
    public func start() {
        let center = NSNotificationCenter.defaultCenter()
        center.addObserver(self, selector: "willShow:", name: UIKeyboardWillShowNotification, object: nil)
        center.addObserver(self, selector: "willHide:", name: UIKeyboardWillHideNotification, object: nil)
        center.addObserver(self, selector: "didShow:", name: UIKeyboardDidShowNotification, object: nil)
        center.addObserver(self, selector: "didHide:", name: UIKeyboardDidHideNotification, object: nil)
        center.addObserver(self, selector: "frameWillChange:", name: UIKeyboardWillChangeFrameNotification, object: nil)
        center.addObserver(self, selector: "frameDidChange:", name: UIKeyboardDidChangeFrameNotification, object: nil)
    }
    
    public func stop() {
        NSNotificationCenter.defaultCenter().removeObserver(self)
    }
    
    func willShow(notification: NSNotification) {
        self.onWillShow?(info: KeyboardNotificationInfo(notification: notification))
    }
    
    func willHide(notification: NSNotification) {
        self.onWillHide?(info: KeyboardNotificationInfo(notification: notification))
    }
    
    func didShow(notification: NSNotification) {
        self.onDidShow?(info: KeyboardNotificationInfo(notification: notification))
    }
    
    func didHide(notification: NSNotification) {
        self.onDidHide?(info: KeyboardNotificationInfo(notification: notification))
    }
    
    func frameWillChange(notification: NSNotification) {
        self.onFrameWillChange?(info: KeyboardNotificationInfo(notification: notification))
    }
    
    func frameDidChange(notification: NSNotification) {
        self.onFrameDidChange?(info: KeyboardNotificationInfo(notification: notification))
    }
    
    deinit {
        self.stop()
    }
}

ViewController

//
//  ViewController.swift
//  KeyboardListener
//
//  Created by Jānis Kiršteins on 15/03/15.
//  Copyright (c) 2015 Jānis Kiršteins. All rights reserved.
//

import UIKit

class ViewController: UIViewController {
    let keyboardListener = KeyboardListener()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        self.keyboardListener.onWillShow = {
            println($0)
        }
    }
    
    override func viewWillAppear(animated: Bool) {
        super.viewWillAppear(animated)
        self.keyboardListener.start()
    }

    override func viewWillDisappear(animated: Bool) {
        super.viewWillDisappear(animated)
        self.keyboardListener.stop()
    }

}