Swift - How to toggle between Play and Pause with UIBarButtonItem - swift

Question

I am trying with the below Swift code in my timer application to start and pause with the same button I have. But it is does not toggle. The button is set with Identifier as "Play" in the IDE. When I run the app, Timer starts and pauses correctly. But it does not toggle button. It always remain as "Play"
#IBAction func pressPausePlay(sender: AnyObject) {
if playPause == false
{
timer.invalidate()
self.playPauseButtonVar = UIBarButtonItem(barButtonSystemItem: UIBarButtonSystemItem.Play, target: self, action: "pressPausePlay")
playPause = true
}
else
{
timer = NSTimer.scheduledTimerWithTimeInterval(1, target: self, selector: Selector("updateTime"), userInfo: nil, repeats: true)
self.playPauseButtonVar = UIBarButtonItem(barButtonSystemItem: UIBarButtonSystemItem.Pause, target: self, action: "pressPausePlay")
playPause = false
}
}

Answer 1

You can use this Example scenarios to toggle between Play and Pause, for Button Titles, Image, Navigation Bar, ToolBar
import UIKit
import AVFoundation
class ViewController: UIViewController {
var myPlayer = AVAudioPlayer()
#IBOutlet var myNaviBar: UINavigationBar! //OUTLET TO NAVIGATION BAR IMPORTANT TO WORK WITH ITS BARBUTTON ITEMS
#IBOutlet var myToolBar: UIToolbar!
//**************START :Bottom LEFT TOOLBAR Bar Button Item***********/
#IBAction func toolBarItemPlay(sender: AnyObject) {
myToolBar.setItems([UIBarButtonItem(barButtonSystemItem: UIBarButtonSystemItem.Pause, target: self, action: "toolBarItemPause:")], animated: true)
myPlayer.play()
}
#IBAction func toolBarItemPause(sender: AnyObject) {
myToolBar.setItems([UIBarButtonItem(barButtonSystemItem: UIBarButtonSystemItem.Play, target: self, action: "toolBarItemPlay:")], animated: true)
myPlayer.pause()
}
//**************END :Bottom LEFT TOOLBAR Bar Button Item***********/
//**************START :Top LEFT Naivation Bar Button Item***********/
#IBAction func leftNavgationbarPlay(sender: UIBarButtonItem) {
myNaviBar.topItem?.leftBarButtonItem = UIBarButtonItem(barButtonSystemItem: .Pause, target: self, action: "leftNavigationbarPause:")
myPlayer.play()
}
//no need of control drag to this one below because we are calling from the above leftNavgationbarPlay's Selector/action
#IBAction func leftNavigationbarPause(sender : UIBarButtonItem) {
myNaviBar.topItem?.leftBarButtonItem = UIBarButtonItem(barButtonSystemItem: .Play, target: self, action: "leftNavgationbarPlay:")
myPlayer.pause()
}
//**************END :Top LEFT Naivation Bar Button Item***********/
//**************START :Top Right Naivation Bar Button Item***********/
#IBAction func naviPlay(sender: UIBarButtonItem) {
//change the topright navigation bar item from SystemItem Play '>' to systemitem pause '||'
// here I am assigning the top left item Play to Bar button item Pause
/* ACTION SELECTOR IMPORTANT. IT MUST CALL THE IB ACTION FUNCTION OF PAUSE AND VICEVERSA, WITH ":" */
myNaviBar.topItem?.rightBarButtonItem = UIBarButtonItem(barButtonSystemItem: UIBarButtonSystemItem.Pause, target: self, action: "naviPause:")
myPlayer.play()
}
#IBAction func naviPause(sender: UIBarButtonItem) {
myNaviBar.topItem?.rightBarButtonItem = UIBarButtonItem(barButtonSystemItem: UIBarButtonSystemItem.Play, target: self, action: "naviPlay:")
myPlayer.pause()
}
//**************END : Top Right Naivation Bar Button Item***********/
//************START :BUTTON IMAGE CHANGE - ">"to "||"************//
#IBAction func imagePlayButton(sender: UIButton) {
let chkImage = sender.currentImage!
if chkImage == UIImage(named: "play.png"){
sender.setImage(UIImage(named: "pause.png"), forState: .Normal)
myPlayer.play()
} else {
sender.setImage(UIImage(named: "play.png"), forState: .Normal)
myPlayer.pause()
}
}
//************END :BUTTON IMAGE CHANGE - ">"to "||"************//
//************START BUTTON TITLE CHANGE - PLAY to PAUSE************//
#IBAction func playButton(sender: UIButton) {
let chkTitle = sender.currentTitle
if chkTitle == "Play" {
sender.setTitle("Pause", forState: .Normal)
myPlayer.play()
} else {
sender.setTitle("Play", forState: .Normal)
myPlayer.pause()
}
}
//************END BUTTON TITLE CHANGE - PLAY to PAUSE************//
#IBAction func naviStop(sender: UIBarButtonItem) {
myPlayer.stop()
myPlayer.currentTime = 0
}
#IBOutlet var sliderUI: UISlider!
#IBAction func mySlider(sender: UISlider) {
myPlayer.volume = sliderUI.value
}
override func viewDidLoad() {
super.viewDidLoad()
let audioFilePath = NSBundle.mainBundle().pathForResource("ARRehman", ofType: "mp3")
//need NSURL from string
do {
myPlayer = try AVAudioPlayer(contentsOfURL: NSURL(fileURLWithPath: audioFilePath!))
}
catch {
print("Some error")
}
}
}

Answer 2

You need to replace bar button items hold in UIToolbar after you assign a new instance to self.playPauseButtonVar.
If you have toolBar or navigationBar outlets:
self.toolBar.setItems([self.playPauseButtonVar], animated: true)
// Or
self.navigationBar.setItems([self.playPauseButtonVar], animated: true)
If your class inherits UIViewController:
self.setToolbarItems([self.playPauseButtonVar], animated: true)
// Or
self.navigationItem.setRightBarButtonItem(self.playPauseButtonVar, animated: true)

Answer 3

Yoichi, thanks for pointing me to the correct place. I removed the references on the Tool bar Outlet variable (bottomToolBar) under "Referencing Outlets". That resolved the error. However I am not able to add the tool bar outlet again, if I add, the error comes back!

Answer 4

it worked with me by creating bar button by code this is my code
import UIKit
class ViewController: UIViewController {
#IBOutlet weak var navigationBar: UINavigationBar!
#IBOutlet weak var displayCountLabel: UILabel!
var buttonPause = UIBarButtonItem()
var buttonPlay = UIBarButtonItem()
var count=0
var timer=NSTimer()
override func viewDidLoad() {
super.viewDidLoad()
buttonPause = UIBarButtonItem(barButtonSystemItem: UIBarButtonSystemItem.Pause, target: self, action: "pauseAction")
buttonPlay = UIBarButtonItem(barButtonSystemItem: UIBarButtonSystemItem.Play, target: self, action: "playAction")
self.navigationBar?.topItem?.leftBarButtonItem = buttonPlay
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
#IBAction func stopTimer(sender: AnyObject) {
timer.invalidate()
count = 0
displayCountLabel.text = "\(count)"
self.navigationBar?.topItem?.leftBarButtonItem = buttonPlay
}
func pauseAction() {
self.navigationBar?.topItem?.leftBarButtonItem = buttonPlay
timer.invalidate()
}
func playAction() {
self.navigationBar?.topItem?.leftBarButtonItem = buttonPause
timer=NSTimer.scheduledTimerWithTimeInterval(1, target: self, selector: Selector("displayCount"), userInfo: nil, repeats: true)
}
func displayCount()
{
count++
displayCountLabel.text = "\(count)"
}
}