Ahad Sheriff Ahad Sheriff - 3 months ago 19
Swift Question

Duplicate Messages Bug

I have a messaging app which contains a tab bar controller, one tab is the messaging view which I built using

JSQMessagesViewController
. When I navigate to another tab and come back to the messaging view, all my messages are duplicated in the view.

Also when a user send a message, it send multiple instances of the same message, which is obviously not optimal for a messaging app.

I tried putting
messages.removeAll()
right before
observeMessages()
in my
viewDidAppear
like a user suggested in this post and it worked for a few seconds, however eventually this made my app crash and the following message was displayed in the console:
fatal error: Index out of range


Here is my code for the said ViewController

class ChatViewController: JSQMessagesViewController, CLLocationManagerDelegate {

// MARK: Properties

//Location
var city: String = ""
var state: String = ""
var country: String = ""
var locationManager = CLLocationManager()
var locationId: String = ""

func getLocation() -> String {
if city == ("") && state == ("") && country == (""){
return "Anonymous"
}
else {
if country == ("United States") {
return self.city + ", " + self.state
}
else {
return self.city + ", " + self.state + ", " + self.country
}
}
}

//Firebase
var rootRef = FIRDatabase.database().reference()
var messageRef: FIRDatabaseReference!
var locationRef: FIRDatabaseReference!

//JSQMessages
var messages = [JSQMessage]()

var outgoingBubbleImageView: JSQMessagesBubbleImage!
var incomingBubbleImageView: JSQMessagesBubbleImage!



override func viewDidLoad() {
super.viewDidLoad()

self.edgesForExtendedLayout = .None

locationManager.delegate = self
locationManager.requestWhenInUseAuthorization()

if CLLocationManager.locationServicesEnabled() {
//collect user's location
locationManager.desiredAccuracy = kCLLocationAccuracyThreeKilometers
locationManager.requestLocation()
locationManager.startUpdatingLocation()
}

title = "Group Chat"
setupBubbles()
// No avatars
collectionView!.collectionViewLayout.incomingAvatarViewSize = CGSizeZero
collectionView!.collectionViewLayout.outgoingAvatarViewSize = CGSizeZero

// Remove file upload icon
self.inputToolbar.contentView.leftBarButtonItem = nil;

messageRef = rootRef.child("messages")
locationRef = rootRef.child("locations")
}

override func viewDidAppear(animated: Bool) {
super.viewDidAppear(animated)

messages.removeAll()

observeMessages()
}

override func viewDidDisappear(animated: Bool) {
super.viewDidDisappear(animated)
}


func locationManager(manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
//--- CLGeocode to get address of current location ---//
CLGeocoder().reverseGeocodeLocation(manager.location!, completionHandler: {(placemarks, error)->Void in

if let pm = placemarks?.first
{
self.displayLocationInfo(pm)
}

})

}


func displayLocationInfo(placemark: CLPlacemark?)
{
if let containsPlacemark = placemark
{
//stop updating location
locationManager.stopUpdatingLocation()

self.city = (containsPlacemark.locality != nil) ? containsPlacemark.locality! : ""
self.state = (containsPlacemark.administrativeArea != nil) ? containsPlacemark.administrativeArea! : ""
self.country = (containsPlacemark.country != nil) ? containsPlacemark.country! : ""

print(getLocation())

}

}


func locationManager(manager: CLLocationManager, didFailWithError error: NSError) {
print("Error while updating location " + error.localizedDescription)
}


override func collectionView(collectionView: JSQMessagesCollectionView!,
messageDataForItemAtIndexPath indexPath: NSIndexPath!) -> JSQMessageData! {
return messages[indexPath.item]
}

override func collectionView(collectionView: JSQMessagesCollectionView!,
messageBubbleImageDataForItemAtIndexPath indexPath: NSIndexPath!) -> JSQMessageBubbleImageDataSource! {
let message = messages[indexPath.item] // 1
if message.senderId == senderId { // 2
return outgoingBubbleImageView
} else {
return incomingBubbleImageView
}
}

override func collectionView(collectionView: UICollectionView,
numberOfItemsInSection section: Int) -> Int {
return messages.count
}

override func collectionView(collectionView: JSQMessagesCollectionView!,
avatarImageDataForItemAtIndexPath indexPath: NSIndexPath!) -> JSQMessageAvatarImageDataSource! {
return nil
}

private func setupBubbles() {
let factory = JSQMessagesBubbleImageFactory()
outgoingBubbleImageView = factory.outgoingMessagesBubbleImageWithColor(
UIColor.jsq_messageBubbleBlueColor())
incomingBubbleImageView = factory.incomingMessagesBubbleImageWithColor(
UIColor.jsq_messageBubbleLightGrayColor())
}

func addMessage(id: String, text: String) {
let message = JSQMessage(senderId: id, displayName: "", text: text)

messages.append(message)
}

override func collectionView(collectionView: UICollectionView,
cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
let cell = super.collectionView(collectionView, cellForItemAtIndexPath: indexPath)
as! JSQMessagesCollectionViewCell

let message = messages[indexPath.item]

if message.senderId == senderId {
cell.textView!.textColor = UIColor.whiteColor()
} else {
cell.textView!.textColor = UIColor.blackColor()
}

return cell
}

override func didPressSendButton(button: UIButton!, withMessageText text: String!, senderId: String!,
senderDisplayName: String!, date: NSDate!) {

self.edgesForExtendedLayout = .None

let itemRef = messageRef.childByAutoId()
let messageItem = [
"text": text,
"senderId": senderId
]
itemRef.setValue(messageItem)

let locRef = locationRef.childByAutoId()
let locItem = [
senderId : [
"location": getLocation()
]
]

locRef.setValue(locItem)

JSQSystemSoundPlayer.jsq_playMessageSentSound()

finishSendingMessage()

}

private func observeMessages() {

let messagesQuery = messageRef.queryLimitedToLast(25)

messagesQuery.observeEventType(.ChildAdded) { (snapshot: FIRDataSnapshot!) in

let id = snapshot.value!["senderId"] as! String
let text = snapshot.value!["text"] as! String

self.addMessage(id, text: text)

self.finishReceivingMessage()
}
}


override func textViewDidChange(textView: UITextView) {
super.textViewDidChange(textView)
}


override func collectionView(collectionView: JSQMessagesCollectionView!, attributedTextForCellBottomLabelAtIndexPath indexPath: NSIndexPath!) -> NSAttributedString! {

let message = messages[indexPath.item]

// Call data I have retrieved below with message
let text = "From: " + getLocation()

if message.senderId == senderId {
return nil
} else {
return NSAttributedString(string: text)
}

}

override func collectionView(collectionView: JSQMessagesCollectionView, layout collectionViewLayout: JSQMessagesCollectionViewFlowLayout, heightForCellBottomLabelAtIndexPath indexPath: NSIndexPath) -> CGFloat {
return kJSQMessagesCollectionViewCellLabelHeightDefault
}


}

Answer

Move observeMessages() from viewDidAppear() and place it in viewDidLoad()

Promise it works when switching back and forth between different views or a segue to a UITableViewController.

Not exactly sure why this is, but I had the same issue and just managed to resolve it, no more duplicate bubbles! I thought it was a problem in relation to UICollectionViewCell but seems like an easy fix.

Let me know if that works for you.

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