I am trying to build a chat application, but I have a problem with this code:
func loadData() {
let FindTimeLineData: PFQuery = PFQuery(className: "Message")
FindTimeLineData.findObjectsInBackgroundWithBlock { (objects: [AnyObject]!, NSError) -> Void in
self.MessagesArray = [String]()
for MessageObject in objects {
let messageText: String? = (MessageObject as! PFObject) ["Text"] as? String
if messageText != nil {
self.MessagesArray.append(messageText!)
}
}
}
}
I need to retrieve data from Parse, but the .findObjectsInBackgroundWithBlock method tells me that it cannot convert a value of type AnyObject into Void in. How can I resolve this problem? Thanks in advance.
Try it like this instead:
var query = PFQuery(className: "Message")
query.findObjectsInBackgroundWithBlock {
(remoteObjects: [PFObject]?, error: NSError?) -> Void in
if error == nil {
print("Retrieved \(remoteObjects!.count) messages from server.")
self.MessagesArray = [String]() // By convention, you should name this "messagesArray" instead, and initialize it outside this method
for messageObject in remoteObjects {
if let messageText: String? = messageObject["Text"] as? String {
self.messagesArray.append(messageText)
}
}
} else {
print("Error: \(error!) \(error!.userInfo)")
}
}
(not properly proof-read, but you should be able to get it to work from this)
For the record, there are LOTS of duplicate questions with this problem - i know, as I had the same problem after converting Parse code to Swift 2.1.
So, please do a little more research before you post a question. Often, SO even hints at you similar questions as you are typing...
As for the answer, the Parse API doesn't force you to cast the object as AnyObject anymore in the completion block of a query, so it can look just like this:
query?.findObjectsInBackgroundWithBlock({ (objects, error) -> Void in
if let messages = objects {
for message in messages {
.... etc
Related
new programmer trying to learn Swift and I'm trying to set my app up to only show the current users post on a parse photosharing database. The first method here in theory should add the current user to the "followingWho" array.
override func viewDidLoad() {
super.viewDidLoad()
let userQuery = PFUser.query()
userQuery?.whereKey("username", equalTo: PFUser.currentUser()!.username!)
userQuery?.findObjectsInBackgroundWithBlock ({
(objects: [PFObject]?, error: NSError?) -> Void in
if error == nil {
//no error
if let objects = objects {
for object in objects {
let followingWho = object["followingWho"] as! NSArray!
self.loadData(followingWho)
}
}
} else {
//error
NSLog("Error")
}
})
self.tableView.reloadData()
}
then my second method here should display the posts and filter out all but the current users
func loadData(followingWho: NSArray) {
let query = PFQuery(className: "Posts")
query.whereKey("addedBy", containedIn: followingWho as! [PFObject])
query.orderByDescending("createdAt")
query.findObjectsInBackgroundWithBlock {
(posts: [PFObject]?, error: NSError?) -> Void in
if (error == nil) {
//No error
//let posts = posts as! [PFObject]
if let posts = posts {
for post in posts {
self.images.append(post["Image"] as! PFFile)
self.imageCaptions.append(post["Caption"] as! String)
self.imageDates.append(post["date"] as! String)
self.imageUsers.append(post["addedby"] as! String)
}
self.tableView.reloadData()
}
} else {
//error
NSLog("Error")
}
}
}
But nothing seems to be working. The code compiles and runs but it seems to only pull up a blank screen loading none of the posts.
This could be the problem, although if it is not the problem, it is certainly a problem: you are trying to update the UI from a background thread. findObjectsInBackgroundWithBlock calls its completion block in the background, and updating UI from the background is a big no-no. Instead, call your UI updates on the main thread:
dispatch_async(dispatch_get_main_queue(), {
//Do your UI updates here
})
This is my initialisation of the array:
var restaurantsArray = [String]()
Here is the query function:
func loadRestaurants(){
let fetchRestaurantsQuery = PFQuery(className: "Restaurants")
fetchRestaurantsQuery.findObjectsInBackgroundWithBlock{ (objects: [PFObject]?, error: NSError?) -> Void in
if error == nil{
//after successfull fetch
print("b")
if let fetchedRestaurants = objects{
print("c")
for fetchedRestaurant in fetchedRestaurants{
print("a")
self.restaurantsArray.append(fetchedRestaurant.objectForKey("Name") as! String)
print(fetchedRestaurant.objectForKey("Name") as! String)
}
}
}else{
// Log details of the failure
print("Error: \(error!) \(error!.userInfo)")
}
}
}
For some reason, the code in the for-loop is never called. Any suggestions to fix this?
Since objects is declared as optional [PFObject]? the proper optional binding syntax is just
if let fetchedRestaurants = objects {
and fetchedRestaurant in fetchedRestaurant is pretty weird.
for fetchedRestaurant in fetchedRestaurants {
Several days I'm trying to crack why my code doesn't work and everything I've tried doesn't give me any result. Heres the deal:
There is a Booking class that contains userFrom who made booking
let query = PFQuery(className: "Booking")
query.whereKey("offer", equalTo: offer.pfObject!)
if self.typeOfUser == .COOK { //! If user is a Cook
query.findObjectsInBackgroundWithBlock({ (objects : [PFObject]?, error : NSError?) -> Void in
if let error = error {
print(error.localizedDescription)
} else {
if let objects = objects {
self.bookings = objects
self.usersIds = [String]()
for object in objects {
let userFrom = object.objectForKey("userFrom") as? PFObject
let userId = userFrom!.objectId! as String
self.usersIds.append(userId)
}
self.getUserInfoForBooking()
} else {
print("Something went wrong")
}
}
})
}
From every user I get objectId and append it to the [String] array. Then I query users with their IDs
private func getUserInfoForBooking() {
let userQuery = PFQuery(className: "User")
userQuery.whereKey("objectId", containedIn: self.usersIds)
userQuery.findObjectsInBackgroundWithBlock({ (objects : [PFObject]?, error : NSError?) -> Void in
if let error = error {
print(error.localizedDescription)
} else {
print(objects!)
if let objects = objects {
for object in objects {
self.users.append(object)
}
self.collectionView.reloadData()
}
}
})
}
In this query I always get an empty array.
Whatever I did, whatever I've changed always [] in response :(
This is the wrong way to query users
let userQuery = PFQuery(className: "User")
Because the class name is private. You should be creating the query as
let userQuery = PFUser.query()
I'm developing a simple iOS application. It's a simple quiz app. I'm using Parse to store my questions, answers etc. I've read all the documentation and cannot find why this code to retrieve an object is not working.
var query = PFQuery(className: "Test_Questions")
query.getObjectInBackgroundWithId("cJzv2JdMej", block: {
(questionObject: PFObject?, error: NSError?) -> Void in
let thisQuestion = questionObject["question"] as! String
//Error here: AnyObject is not convertible to String
})
Your help would be much appreciated!
Console Output:
Optional(What statement must come before an else statement?)
You should try this instead:
var query = PFQuery(className: "Test_Questions")
query.getObjectInBackgroundWithId("cJzv2JdMej", block: {
(questionObject: PFObject?, error: NSError?) -> Void in
if error == nil {
println(questionObject)
//if there's info in the console you know the object was retrieved
let thisQuestion = questionObject["question"] as? String
} else {
println("Error occurred retrieving object")
}
})
If that doesn't work you can also try let thisQuestion = questionObject.valueForKey("question"). Also make sure that Parse is actually returning an object by adding a print statement such as println(questionObject) after it has been retrieved so that you know Parse is returning an object.
Got it!
var query = PFQuery(className: "Test_Questions")
query.getObjectInBackgroundWithId("cJzv2JdMej", block: {
(questionObject: PFObject?, error: NSError?) -> Void in
let thisQuestion: AnyObject! = questionObject!.valueForKey("question")
self.question.text = thisQuestion as? String
})
I am facing an issue when trying to delete objects from Parse after having queried them.
My code:
var query = PFQuery(className:"sendMessage")
query.whereKey("messageSent", equalTo: PFUser.currentUser()!.username!)
query.whereKey("messageReceived", equalTo: self.nameLabel!.text!)
query.findObjectsInBackgroundWithBlock({ (objects, NSError) -> Void in
if objects != nil {
if let objects = objects as? [PFObject] {
for object in objects {
print(object["message"])
/// here I would go: object.deleteInBackground()
object.save()
}
}
}
})
But it seems that I cannot find the right way to do so. Any insights ?
var query = PFQuery(className:"sendMessage")
let username = PFUser.currentUser()?.username
query.whereKey("messageSent", equalTo: username)
query.whereKey("messageReceived", equalTo: self.nameLabel!.text!)
query.findObjectsInBackgroundWithBlock({ (objects:[AnyObject]?, error:NSError) -> Void in
if error == nil {
if let objects = objects as? [PFObject] {
for object in objects {
let deletemessage = object["message"] as! String
print(deletemessage)
object.delete()
}
}
}
else {
println("Error")
}
})
I have used deleteEventually() with success before, together with PFObject(withoutDataWithClassName: YourClassName, objectId: YourObjectID).
If that works I wouldn't know why, but well :)
(as stated by Hector in this Parse Question (Objective-C): https://www.parse.com/questions/delete-row)
for object in objects {
print(object["message"]
var toDelete = PFObject(withoutDataWithClassName: "sendMessage", objectId: object.objectID)
toDelete.deleteEventually()
}