I am attempting to integrate some JSSAlertViews within one of my ViewControllers, but for some odd reason, when I run my project, the alert views do not show. So to make sure it wasn't any error with coding, I created an exact pseudo project to replicate the ViewController of my original project, down to it's UI elements on the storyboard. I copied the exact code from my original project onto the new ViewController, ran it, and everything worked. Im stuck onto figuring out, why won't it work on my original project??
here is the logic i used:
#IBAction func resetPass(sender: AnyObject) {
actview.hidden = false
actview.startAnimating()
PFUser.requestPasswordResetForEmailInBackground(emailReset.text) {
(success:Bool, error:NSError?) ->Void in
if(success){
let yesMessage = "Email was sent to you at \(self.emailReset.text)"
dispatch_async(dispatch_get_main_queue()) {
self.actview.stopAnimating()
JSSAlertView().success(self, title:"Great Success", text:yesMessage)
}
}
if(error != nil){
let errorMessage:String = error!.userInfo!["error"] as! String
dispatch_async(dispatch_get_main_queue()) {
self.actview.stopAnimating()
JSSAlertView().warning(self, title:"Woah There", text:errorMessage)
}
}
}
}
I set a breakpoint on a call of one of the JSSAlertView's , expanded the element in my console and got this :
Is this a memory management error and reason why they aren't visible? how do i fix this?
here is the Git if you want to check it out, its awesome: https://github.com/stakes/JSSAlertView
Anything with the UI needs to be done on the main thread, and you're calling the Parse function on the background thread (via requestPasswordResetForEmailInBackground).
So to get your alerts to appear on the main thread, you need to add a little GCD magic:
#IBAction func resetPass(sender: AnyObject) {
actview.hidden = false
actview.startAnimating()
PFUser.requestPasswordResetForEmailInBackground(emailReset.text) {
(success:Bool, error:NSError?) ->Void in
if(success){
self.actview.stopAnimating()
let yesMessage = "Email was sent to you at \(self.emailReset.text)"
dispatch_async(dispatch_get_main_queue()) {
self.successMessage(yesMessage)
}
};
if(error != nil){
self.actview.stopAnimating()
let errorMessage:String = error!.userInfo!["error"] as! String
dispatch_async(dispatch_get_main_queue()) {
self.failureMessage(errorMessage)
}
}
}
}
See my addition of the "dispatch_async(dispatch_get_main_queue())" lines?
Related
I'm trying out the Snap Kit Framework from Snapchat using their sample code but when running the code nothing happens and no error is thrown.
import SCSDKCreativeKit
let snap = SCSDKNoSnapContent()
snap.sticker = SCSDKSnapSticker(stickerImage: UIImage(named: "story_share.png")!)
snap.caption = "Snap on Snapchat!"
snap.attachmentUrl = profileURL.absoluteString
SCSDKSnapAPI().startSending(snap) { (error: Error?) in
print(error)
}
The logs don't indicate an error either:
myapp[853:121028] [SnapKit] Dynamic config update status: success
Things I've tried or insured are correct:
My app is registered online with the correct bundle id, my test snapchat username and the creative kit is selected
the development key is in the Info.plist file as SCSDKClientId
snapchat is in the list of LSApplicationQueriesSchemes
the code runs on the main thread
using their userInteractionEnabled trick doesn't make a difference
I'm using carthage and embed the core and creative framework as usual
What could be the reason why this doesn't work?
I found the disappointing answer that it only works using the deprecated method call:
SCSDKSnapAPI(content: snap).startSnapping() { (error: Error?) in
...
}
I hope that Snapchat fixes their terrible framework in the future. If anyone knows an actual solution, please let me know and I'll accept your answer.
SCSDKSnapAPI() needs to be defined as a class variable. Your code doesn't show the implementation, but I had the same issue when I instantiated SCSDKSnapAPI() in a func() instead of at the Class level.
Here's an implementation that I found which works as intended:
class CreateViewController: UIViewController {
fileprivate lazy var snapAPI = {
return SCSDKSnapAPI()
}()
#IBAction func sendSnap2(_ sender: Any) {
//self.snapAPI = SCSDKSnapAPI() <<DO NOT DO THIS>>
let snap2 = SCSDKNoSnapContent()
view.isUserInteractionEnabled = false
snapAPI.startSending(snap) { [weak self] (error: Error?) in
self?.view.isUserInteractionEnabled = true
if (error != nil) {
print("Error Unknown", error!)
}
else {
print("no error")
}
}
}
I need the "getUserInfo" to complete before I execute the next section of code (the push to storyboard). Currently the "getUserInfo" is still in process while the storyboard push executes. How can I make these execute in order? I'm need to keep these 2 functions separate, so putting the code in the completion handler of loginUser isn't a good solution. Many thanks to those who are smarter than me :)
func loginUser() {
PFUser.logInWithUsernameInBackground(txtEmailAddress.text, password:txtPassword.text) {
(user: PFUser?, error: NSError?) -> Void in
if user != nil {
// Successful login.
self.txtPassword.resignFirstResponder()
self.txtEmailAddress.resignFirstResponder()
getUserInfo()
// Push to Main.storyboard.
let storyboard = UIStoryboard(name: "Main", bundle: NSBundle.mainBundle())
let viewController: AnyObject = storyboard.instantiateInitialViewController()
self.presentViewController(viewController as! UIViewController, animated: true, completion: nil)
} else {
// The login failed. Display alert.
self.displayAlert("Error", message: "Login incorrect")
}
}
}
func getUserInfo() {
let currentUser = PFUser.currentUser()
let userQuery = PFQuery(className: "_User")
userQuery.whereKey("username", equalTo: PFUser.currentUser()!.username!)
userQuery.findObjectsInBackgroundWithBlock({ (results:[AnyObject]?, error:NSError?) -> Void in
if error == nil {
for result in results! {
userType = result["userType"] as! String
if userType == "admin" {
user = "AdminSetting"
} else {
user = "StandardSetting"
}
}
}
})
}
What you want to do is make the asynchronous function (the one with the completion handler) synchronous, so that it returns immediately. However that's usually a bad idea, because if the execution stops in the main thread, the user can't do anything and your app is stuck until the code continues again. This might take a couple seconds depending on the connection, which isn't very good, you should really update your UI asynchronous on asynchronous tasks. There usually aren't good reasons to do something like this, if you have them though, you can tell me.
You could also execute your storyboard code within getUserInfo() as a block/closure passed in as a parameter. That way you can ensure it is executed when the async call in getUserInfo completes
What Shadowman suggested is the correct/most elegant solution.
Here is an example:
func getUserInfo(completion: (results:[AnyObject]?, error:NSError?) -> Void) {
let currentUser = PFUser.currentUser()
let userQuery = PFQuery(className: "_User")
userQuery.whereKey("username", equalTo: PFUser.currentUser()!.username!)
userQuery.findObjectsInBackgroundWithBlock(completion)
}
This way, you get back the actual results from your call after it finished, handy, eh ?
And here is how you call it:
self.getUserInfo { (results, error) -> Void in
// Here the results are already fetched, so proceed with your
// logic (show next controller or whatever...)
if error == nil {
for result in results! {
userType = result["userType"] as! String
if userType == "admin" {
user = "AdminSetting"
} else {
user = "StandardSetting"
}
}
}
// depending on whether this will still run in a background thread, you might have to dispatch this code to the main thread.
// you can check whether this code block is called on the main thread
// by checking if NSThread.isMainThread() returns true
// if not, you will need to use this dispatch block!
dispatch_async(dispatch_get_main_queue(), { () -> Void in
// only call UI code in main thread!
// MOVE TO NEXT controller in here!
})
}
What I have
I don't understand the nature of the problem.
I have 2 View Controllers :
1) FeedViewController ,which shows events in tableview
2) EventViewController, pushed when you press on event.
When Feed Loads, it start asynchronous loadings of all images of all events.
It's done for each event by following function:
EventsManager().loadProfilePictureById(event.profilePictureID as String, currentProgress: event.profilePictureProgress, completionHandler: {
(progress:Double, image:UIImage!, error:NSError!) -> Void in
event.profilePictureProgress = progress
if image != nil {
event.profilePicture = image
}
if (error == nil){
if (self.tableView.headerViewForSection(index) != nil){
var header:eventHeaderView = self.tableView.headerViewForSection(index) as! eventHeaderView
header.updateProfilePicture(
self.eventsManager.events[index].profilePictureID as String,
progress: self.eventsManager.events[index].profilePictureProgress,
image: self.eventsManager.events[index].profilePicture)
}
}else{
println("Error:" + error.description)
}
})
Here is how I push EventViewController:
func PushEventViewController(sender:UITapGestureRecognizer)->Void{
let ViewSender = sender.view!
let selectedRow = ViewSender.tag
//let Cell:HomeEventTableViewCell = TimelineEventTable.cellForRowAtIndexPath(SelectedIndexPath) as HomeEventTableViewCell
dispatch_async(dispatch_get_main_queue(), {
() -> Void in
let VC:EventViewController = self.storyboard?.instantiateViewControllerWithIdentifier("EventViewController") as! EventViewController
VC.event = self.eventsManager.events[selectedRow]
self.navigationController?.pushViewController(VC, animated: true)
})
}
Problem
The problem is that if I press on event and push EventViewController before image is downloaded (completion handlers are still getting called) it crashes app.
Assumptions
I struggled with this for days and couldn't find a solution,
but my assumptions are that completion handler called after
Crash happens when it tries to execute following line after EventViewController was pushed:
event.profilePictureProgress = progress
if image != nil {
event.profilePicture = image
}
I assume when new view controller is pushed , event object which is used in completion handler is being deallocated
Found out where the problem was, the issue was that variable event.profilePictureProgress was declared as dynamic var (I was going to take advantage of that to add observer to it after).
I've been getting an EXC_BAD_ACCESS error/crash when I engage in a specific action within my application. Figuring that this was a memory management issue, I enabled NSZombies to help me decipher the issue. Upon the crash, my console gave me the following message:
heres my stack trace:
and the new error highlighting my app delegate line:
Now being the debugger is referring to a UIActivityIndicatorRelease, and the only line of code highlighted in my stack trace is the 1st line in my delegate, is there an issue with my Activity Indicator UI Element? Here is the logic within my login action ( which forces the crash every time ):
#IBAction func Login(sender: AnyObject) {
activityIND.hidden = false
activityIND.startAnimating()
var userName = usernameText.text
var passWord = passwordText.text
PFUser.logInWithUsernameInBackground(userName, password: passWord) {
(user, error: NSError?) -> Void in
if user != nil {
dispatch_async(dispatch_get_main_queue()) {
self.performSegueWithIdentifier("loginSuccess", sender: self)
}
} else {
self.activityIND.stopAnimating()
if let message: AnyObject = error!.userInfo!["error"] {
self.message.text = "\(message)"
}
}
}
}
is there an error within it?
All your code that manipulates UI objects absolutely, positively must be done from the main thread. (and so it should be in a call to dispatch_async(dispatch_get_main_queue()) as #JAL says in his comment.
That includes not just the self.activityIND.stopAnimating() line, but the code that sets label text as well (any code that manipulates a UIKit object like a UIView).
Your if...else clause should look something like this:
if user != nil
{
dispatch_async(dispatch_get_main_queue())
{
self.activityIND.stopAnimating()
self.performSegueWithIdentifier("loginSuccess", sender: self)
}
}
else
{
dispatch_async(dispatch_get_main_queue())
{
self.activityIND.stopAnimating()
if let message: AnyObject = error!.userInfo!["error"]
{
self.message.text = "\(message)"
}
}
}
So it turns out, in my viewDidLoad() I had the following code in attempt to hide the indicator on the load:
UIActivityIndicator.appearance().hidden = true
UIActivityIndicatorView.appearance().hidesWhenStopped = true
not knowing this would deallocate the indicator for the remainder of the application so when i called the following in my login logic:
activityIND.hidden = false
activityIND.startAnimating()
i was sending a message to an instance that was no longer available, causing the crashes. So all i did was adjust my code in viewDidLoad()
to :
activityIND.hidden = true
activityIND.hidesWhenStopped = true
using the name of the specific outlet I created rather than the general UIActivityIndicatorView
All UI related operation should execute in Main Thread, i.e., within
dispatch_async(dispatch_get_main_queue(){}
block
#IBAction func Login(sender: AnyObject) {
activityIND.hidden = false
activityIND.startAnimating()
var userName = usernameText.text
var passWord = passwordText.text
PFUser.logInWithUsernameInBackground(userName, password: passWord) {
(user, error: NSError?) -> Void in
if user != nil {
dispatch_async(dispatch_get_main_queue()) {
self.performSegueWithIdentifier("loginSuccess", sender: self) //UI task
}
}
else {
dispatch_async(dispatch_get_main_queue())
{
self.activityIND.stopAnimating() //UI task
if let message: AnyObject = error!.userInfo!["error"]
{
self.message.text = "\(message)" //UI task
}
};
}
}
}
Refer some good articles on Concurrency here and here
I've written my code for retrieving images from my Parse data console so that they will appear in my Storyboard for my Swift app, but I'm not sure how to make an IBOutlet connect to the UIImageView I added to my Storyboard so that the image from Parse will actually appear in its place. Here's the code I have so far in my ViewController:
var imageResources : Array<UIImage> = []
override func viewDidLoad() {
super.viewDidLoad()
func loadImages(){
var query2 = PFQuery(className: "VoteCount")
query.findObjectsInBackgroundWithBlock ({(objects:[AnyObject]!, error: NSError!) in
if(error == nil){
let imageObjects = objects as [PFObject]
for object in objects {
let thumbNail = voteCount1["image"] as PFFile
thumbNail.getDataInBackgroundWithBlock({
(imageData: NSData!, error: NSError!) -> Void in
if (error == nil) {
let image = UIImage(data:imageData)
self.imageResources.append(image!)
println(image)
}
})
}
}
else{
println("Error in retrieving \(error)")
}
})
}
}
What kind of IBOutlet do I make that connects to the UIImageView I've added to my Main.storyboard? I'm just not sure what to name it that will call the image from Parse that I'm trying to retrieve.
control-drag from your UIImageView to your Swift file, outside the methods but inside the implementation. name it myImageView.
You can't call println on an image.
Then after the line if (error == nil) { try the following
if let image = UIImage(data:imageData) {
dispatch_async(dispatch_get_main_queue()) {
self.myImageView.image = image
}
}
Or something to that effect. You need to be sure:
the image exists
you do anything with UI updates on the main thread (that's what dispatch_async(dispatch_get_main_queue()) {} accomplishes
Try it and let me know if that helps. I'm on the road right now but when I get a chance to sit I'll circle back and check this out.
One last trick: you can put a breakpoint on lines where you get an image. Then when the application pauses, you can hover over the word image in the line if let image = UIImage(data:imageData) { and click on the eye icon in the popup. You should then be able to view the image from Parse. If the image doesn't appear when you click the eye icon, you probably have additional debugging to do (does the image exist, is your logic up to that point correct, etc).