Swift link Image data from Parse array using segues to secondViewController [duplicate] - ios

Question

This question already has answers here:
Swift link Image from Parse array using segues to secondViewController
(2 answers)
Closed 7 years ago.
Here is my code, i am trying to use the "prepareForSegue" function to send an image from tableViewController (firstViewController) to my detailedViewController (secondViewController). I have managed to populate my firstViewController from the parse cloud successfully and I have managed to get my secondViewController Labels to update, but i can not get the imageView to update. I have posted my code below
firstViewController
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
let eventDetailVC: EventDetailsVC = segue.destinationViewController as! EventDetailsVC
if let selectedArrayIndex = tableView.indexPathForSelectedRow?.row {
eventDetailVC.detailNameLabel = postedEvents[selectedArrayIndex]
eventDetailVC.detailAddressLabel = postedAddress[selectedArrayIndex]
eventDetailVC.detailCityLabel = postedCity[selectedArrayIndex]
eventDetailVC.detailStateLabel = postedState[selectedArrayIndex]
eventDetailVC.detailStartLabel = postedStart[selectedArrayIndex]
eventDetailVC.detailEndLabel = postedEnd[selectedArrayIndex]
eventDetailVC.detailPriceLabel = postedPrices[selectedArrayIndex]
eventDetailVC.detailDescriptionLabel = postedDescription[selectedArrayIndex]
// The error is here....i think
postedImages[selectedArrayIndex].getDataInBackgroundWithBlock { (data, error) -> Void in
if let downloadedImage = UIImage(data: data!) {
eventDetailVC.detailImageView.image = downloadedImage
}
}
}
}
secondViewController
var detailNameLabel = String()
var detailDescriptionLabel = String()
var detailPriceLabel = String()
var detailStartLabel = String()
var detailEndLabel = String()
var detailAddressLabel = String()
var detailCityLabel = String()
var detailStateLabel = String()
var detailImageView = UIImageView()
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
detailName.text = detailNameLabel
detailDescription.text = detailDescriptionLabel
detailPrice.text = detailPriceLabel
detailStart.text = detailStartLabel
detailEnd.text = detailEndLabel
detailAddress.text = detailAddressLabel
detailCity.text = detailCityLabel
detailState.text = detailStateLabel
// its this line below....i think
detailImage.image = detailImageView.image
}
Please can someone help me figure this out, Im kinda new to this whole thing

Answer 1

I don't see where "detailImage" is defined, so this is assuming it is a property on .
Set a breakpoint inside the "getDataInBackgroundWithBlock" completion block to see if and when it is getting called. If it is getting called add "eventDetailVC.detailImage.image = downloadedImage" to the completion block.

Answer 2

Your problem is that the download of the image completes asynchronously, so by the time it has completed, your view controller has already executed the line detailImage.image = detailImageView.image with a nil image.
Rather than putting all of the code in your viewDidLoad, define didSet observers for your properties that set the appropriate UI elements. This way any time the property is updated it will automatically update the UI element;
Finally, your properties have confusing names, detailAddressLabel is actually a string and the UILabel instance seems to be named detailAddress - this has caused you to define detailImageView as UIImageView instead of a UIImage.
My suggested implementation is (after changing the names of IBOutlets and other properties to make more sense):
class someViewController : UIViewController {
#IBOutlet var detailNameLabel : UILabel! {
didSet {
self.detailNameLabel?.text=self.detailName
}
}
#IBOutlet var detailDescriptionLabel : UILabel! {
didSet {
self.detailDescriptionLabel?.text=self.detailDescription
}
}
#IBOutlet var detailPriceLabel : UILabel! {
didSet {
self.detailPriceLabel?.text=self.detailPrice
}
}
#IBOutlet var detailStartLabel : UILabel! {
didSet {
self.detailStartLabel?.text=self.detailStart
}
}
#IBOutlet var detailEndLabel : UILabel! {
didSet {
self.detailEndLabel?.text=self.detailEnd
}
}
#IBOutlet var detailAddressLabel : UILabel! {
didSet {
self.detailAddressLabel?.text=self.detailAddress
}
}
#IBOutlet var detailCityLabel : UILabel! {
didSet {
self.detailCityLabel?.text=self.detailCity
}
}
#IBOutlet var detailImageView : UIImageView! {
didSet {
self.detailImageView?.image=self.detailImage
}
}
var detailName : String = "" {
didSet {
self.detailNameLabel?.text=self.detailName
}
}
var detailDescription : String = "" {
didSet {
self.detailDescriptionLabel?.text=self.detailDescription
}
}
var detailPrice : String = "" {
didSet {
self.detailPriceLabel?.text=self.detailPrice
}
}
var detailStart : String = "" {
didSet {
self.detailStartLabel?.text=self.detailStart
}
}
var detailEnd : String = "" {
didSet {
self.detailEndLabel?.text=self.detailEnd
}
}
var detailAddress: String = "" {
didSet {
self.detailAddressLabel?.text=self.detailAddress
}
}
var detailCity : String = "" {
didSet {
self.detailCityLabel?.text=self.detailCity
}
}
var detailImage : UIImage? {
didSet {
self.detailImageView?.image=self.detailImage
}
}
}