CODEWITHSUNDEEP
iosswifturl
Macondo
Macondo

Reputation: 369

How to display an image using URL?

The error is: "fatal error: unexpectedly found nil while unwrapping an Optional value"

I am doing the following in ViewController:

var imageURL:UIImageView!

override func viewDidLoad() {
    super.viewDidLoad()
    let url = NSURL(string:"http://cdn.businessoffashion.com/site/uploads/2014/09/Karl-Lagerfeld-Self-Portrait-Courtesy.jpg")
    let data = NSData(contentsOfURL:url!)
    if data!= nil {
        imageURL.image = UIImage(data:data!)
    }
}

I really don't understand why it will report an error on 

imageURL.image = UIImage(data:data!)

while I already told it not to proceed if data is nil. It is not the problem of the link. Nor is there problem with the "data". I tried to print it and it was not nil.

Upvotes: 33

Views: 93868

Answers (16)

Vishal Davara
Vishal Davara

Reputation: 91

Swift 4: A simple loader for small images (ex: thumbnails) that uses NSCache and always runs on the main thread:

class ImageLoader {

  private static let cache = NSCache<NSString, NSData>()

  class func image(for url: URL, completionHandler: @escaping(_ image: UIImage?) -> ()) {

    DispatchQueue.global(qos: DispatchQoS.QoSClass.background).async {

      if let data = self.cache.object(forKey: url.absoluteString as NSString) {
        DispatchQueue.main.async { completionHandler(UIImage(data: data as Data)) }
        return
      }

      guard let data = NSData(contentsOf: url) else {
        DispatchQueue.main.async { completionHandler(nil) }
        return
      }

      self.cache.setObject(data, forKey: url.absoluteString as NSString)
      DispatchQueue.main.async { completionHandler(UIImage(data: data as Data)) }
    }
  }
}

Upvotes: 0

Azaharuddin Mohammad
Azaharuddin Mohammad

Reputation: 57

 let urlImg = NSURL(string:"https://firebasestorage.googleapis.com/v0/b/fanism-dccfe.appspot.com/o/Heros%2FIMG-20171116-WA0003.png?alt=media&token=b31a6d9e-cea6-422a-b198-82365abd845e")

    data = NSData.init(contentsOf: urlImg! as URL)
    if data != nil {
        imageView?.image = UIImage(data:data! as Data) //**Here imageView our ImageView outlet  **//
    }

Upvotes: 0

Sandip Gill
Sandip Gill

Reputation: 1100

This is the code for it. I have used this you do not need to include classes or anything else. Just use this extension. This is very fast. 

extension UIImageView {
    public func imageFromURL(urlString: String) {

        let activityIndicator = UIActivityIndicatorView(activityIndicatorStyle: .gray)
        activityIndicator.frame = CGRect.init(x: 0, y: 0, width: self.frame.size.width, height: self.frame.size.height)
        activityIndicator.startAnimating()
        if self.image == nil{
            self.addSubview(activityIndicator)
        }

        URLSession.shared.dataTask(with: NSURL(string: urlString)! as URL, completionHandler: { (data, response, error) -> Void in

            if error != nil {
                print(error ?? "No Error")
                return
            }
            DispatchQueue.main.async(execute: { () -> Void in
                let image = UIImage(data: data!)
                activityIndicator.removeFromSuperview()
                self.image = image
            })

        }).resume()
    }
}

Upvotes: 1

yo2bh
yo2bh

Reputation: 1436

Swift 3.0 for downloading image and parsing json using the URLSession and URLRequest.

static func getRequest(_ urlString:String, completion:@escaping (Any?) -> ()) {
    guard let url = URL(string: urlString) else { return }
    let session = URLSession.shared
    let request = URLRequest(url: url)

    let task = session.dataTask(with: request, completionHandler: {
        (data, response, error) -> Void in

        if let data = data {
            do {
                let json = try JSONSerialization.jsonObject(with: data, options: [])
                completion(json)
            } catch {
                print(error)
            }
        }
    })
    task.resume()
}

static func downloadImage(_ url: String, completion:@escaping(UIImage?)->()) {
    let aUrl = URL(string: url)
    DispatchQueue.global().async {
        do {
            let data = try? Data(contentsOf: aUrl!)
            completion(UIImage(data: data!))
        } catch {
            print("Unable to download image")
        }
    }
}

Upvotes: 0

Anirudh R.Huilgol.
Anirudh R.Huilgol.

Reputation: 859

Here is my code might help you

Swift 2:

extension UIImageView{

    func setImageFromURl(stringImageUrl url: String){

        if let url = NSURL(string: url) {
            if let data = NSData(contentsOfURL: url) {
                self.image = UIImage(data: data)
            }        
        }
    }
}

Swift 3:

extension UIImageView{

func setImageFromURl(stringImageUrl url: String){

      if let url = NSURL(string: url) {
         if let data = NSData(contentsOf: url as URL) {
            self.image = UIImage(data: data as Data)
         }
      }
   }
}

Usage 

 let imgURL = "https://yourdomain.com/picturepath/picname.png" // or jpg
 self.myImage.setImageFromURl(stringImageUrl: imgURL)

if you are using HTTP connection and not https don't forget to add this

App Transport Security Settings as dictionary and into it Allow Arbitrary Loads as Boolean with value YES like in the below figure enter image description here

Upvotes: 17

Andrew
Andrew

Reputation: 38029

It is pretty big possibility that you are using Alamofire and if so it is as simple as:

imageView.af_setImage(withURL: url)

Upvotes: 2

Async-
Async-

Reputation: 3289

Swift 3: (image in this case is 64 bit binary data)

if let url = NSURL(string: route) {
            if let imageData = NSData(contentsOf: url as URL) {
                let str64 = imageData.base64EncodedData(options: .lineLength64Characters)
                let data: NSData = NSData(base64Encoded: str64 , options: .ignoreUnknownCharacters)!
                let dataImage = UIImage(data: data as Data)

            }        
        }

Upvotes: 3

pawan gupta
pawan gupta

Reputation: 251

You can set image in image view by using UIImageView+AFNetworking

Frist you drag the UIImageView+AFNetworking objective c classes in your project and import UIImageView+AFNetworking.h class in your project's bridge header file. And use this line to set image with placeholder in imageview. by this you can set multiple image in a view without any stuck.

yourImageview.setImageWithURL(NSURL(string: self.yourArray.objectAtIndex(indexPath.row).objectForKey("imageurl") as! String), placeholderImage: UIImage(named:"NoUserimage.png"))

Upvotes: 3

Stack_Striker
Stack_Striker

Reputation: 36

Methode

extension UIImage {

/// Loads image asynchronously
///
/// - Parameters:
///   - url: URL of the image to load
///   - callback: What to do with the image

class func loadFromURL(url: NSURL, callback: (UIImage)->()) {
    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0), {

        let imageData = NSData(contentsOfURL: url)
        if let data = imageData {
            dispatch_async(dispatch_get_main_queue(), {
                if let image = UIImage(data: data) {
                    callback(image)
                }
            })
        }
    })
}

}

Usage

    let logoUrl = ImageService().buildImageString((self.uiConfig?.headerImage)!, imageMode: .Uniform, size: self.headerImage.frame.size)
    UIImage.loadFromURL(logoUrl, callback: { (image: UIImage) -> () in
        self.headerImage.image = image
    })

Upvotes: 0

Gourav Joshi
Gourav Joshi

Reputation: 2419

Here I have an approach from which you will not get any kind of crash when downloading image. Now currently you are using the following code:

override func viewDidLoad() {
    super.viewDidLoad()
    let url = NSURL(string:"http://cdn.businessoffashion.com/site/uploads/2014/09/Karl-Lagerfeld-Self-Portrait-Courtesy.jpg")
    let data = NSData(contentsOfURL:url!)
    if data!= nil {
        imageURL.image = UIImage(data:data!)
    }
}

Now change the code with this one, If you are continue with this approach:

override func viewDidLoad() {
    super.viewDidLoad()
    let url = NSURL(string:"http://cdn.businessoffashion.com/site/uploads/2014/09/Karl-Lagerfeld-Self-Portrait-Courtesy.jpg")
    let data = NSData(contentsOfURL:url!) 

    // It is the best way to manage nil issue. 
    if data.length > 0 {
        imageURL.image = UIImage(data:data!)
    } else {
        // In this when data is nil or empty then we can assign a placeholder image 
        imageURL.image = UIImage(named: "placeholder.png")
    }
}

And I am sure that If you are used it your nil crash will be solved.

Upvotes: 6

iOS_Developer
iOS_Developer

Reputation: 183

NSURL(string: "")

This returns an optional value. Take a look at description of it. It says An NSURL object initialized with URLString. If the URL string was malformed, returns nil.

In your code you are trying to url! which will get crash whenever the value of url is nil.

Upvotes: 1

Anita Nagori
Anita Nagori

Reputation: 747

You can use SDWebImage for display image from URL https://github.com/rs/SDWebImage

[cell.imageView sd_setImageWithURL:[NSURL URLWithString:@"http://www.domain.com/path/to/image.jpg"]
                      placeholderImage:[UIImage imageNamed:@"placeholder.png"]];

Upvotes: 4

Rizwan Shaikh
Rizwan Shaikh

Reputation: 2904

Your code is right, just use:

if data != nil {

}

Upvotes: 2

Airspeed Velocity
Airspeed Velocity

Reputation: 40963

The error is most likely that imageURL is nil. Are you assigning it a value elsewhere in the code, or is it actually @IBOutlet in the real code? If you do not assign a value to it, it will be nil - but its type of UIImageView! means it is an "implicitly unwrapped optional" which means the compiler won't stop you using it even if it is nil, but will crash at runtime with the error you're getting.

The rest of the code is correct (assuming the missing space before != is a typo not in your compiling code), but you would be better off using if let to unwrap your optionals rather than checking them against nil and then using the force-unwrap operator:

if let url = NSURL(string: "http://etc...") {
    if let data = NSData(contentsOfURL: url) {
        imageURL.image = UIImage(data: data)
    }        
}

If you happen to be using the Swift 1.2 beta, you can combine the two ifs together:

if let url  = NSURL(string: "http://etc..."),
       data = NSData(contentsOfURL: url)
{
        imageURL.image = UIImage(data: data)
}

Or, if you prefer, use flatMap:

imageURL.image =
    NSURL(string: "http://etc...")
    .flatMap { NSData(contentsOfURL: $0) }
    .flatMap { UIImage(data: $0) }

Upvotes: 57

Carlos Gonzlez-Baquerizo Gmez
Carlos Gonzlez-Baquerizo Gmez

Reputation: 11

The problem is that at viewDidLoad the imageURL UIImageView may have not been set yet. I'd use optional chaining in case the UIImageView is nil

imageURL?.image = UIImage(data:data!)

I'd set the UIImageView's image at viewDidLayoutSubviews(), at which point you're sure that the ViewController's outlets have been set.

The way I'd do it would look like this:

@IBOutlet weak var imageURL: UIImageView!
var data: NSData?

override func viewDidLoad() {
    super.viewDidLoad()
    let url = NSURL(string:"http://cdn.businessoffashion.com/site/uploads/2014/09/Karl-Lagerfeld-Self-Portrait-Courtesy.jpg")
    data = NSData(contentsOfURL:url!)
    if data != nil {
        imageURL?.image = UIImage(data:data!)
    }
}

override func viewDidLayoutSubviews() {
    if data != nil {
        imageURL.image = UIImage(data:data!)
    }
}

Upvotes: 1

Sulejman Sarajlija
Sulejman Sarajlija

Reputation: 424

Try writing: 

if data != nil {}

instead:

if data!= nil {}

Compiler is maybe confusing exclamation mark with operation to unwrap the optional value.

Upvotes: 3

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