Can I load a UIImage from a URL

Question

I have a URL for an image  got it from UIImagePickerController  but I no longer have the image in memory  the URL was saved from a previous run of the app    Can I reload the UIImage from the URL again     I see that UIImage has a imageWithContentsOfFile  but I have a URL   Can I use NSData s dataWithContentsOfURL  to read the URL   EDIT1    based on  Daniel s answer I tried the following code but it doesn t work     NSLog    s        PRETTY FUNCTION    photoURL        if  photoURL        NSURL  aURL    NSURL URLWithString photoURL       NSData  data     NSData alloc  initWithContentsOfURL aURL       self photoImage    UIImage imageWithData data        data release       When I ran it the console shows   - PhotoBox willMoveToWindow   file   localhost Users gary Library Application 20Support iPhone 20Simulator 3 2 Media DCIM 100APPLE IMG 0004 JPG     - NSURL length   unrecognized selector sent to instance 0x536fbe0     Terminating app due to uncaught exception  NSInvalidArgumentException   reason       - NSURL length   unrecognized selector sent to instance 0x536fbe0    Looking at the call stack  I m calling URLWithString  which calls URLWithString relativeToURL   then initWithString relativeToURL   then  CFStringIsLegalURLString  then CFStringGetLength  then forwarding prep 0  then forwarding  then - NSObject doesNotRecognizeSelector    Any ideas why my NSString  photoURL s address is 0x536fbe0  doesn t respond to length   Why does it say it doesn t respond to - NSURL length    Doesn t it know that param is an NSString  not a NSURL   EDIT2    OK  the only problem with the code is the string to URL conversion   If I hardcode the string  everything else works fine   So something is wrong with my NSString and if I can t figure it out  I guess that should go in as a different question   With this line inserted  I pasted the path from the console log above   it works fine   photoURL     file   localhost Users gary Library Application 20Support iPhone 20Simulator 3 2 Media DCIM 100APPLE IMG 0004 JPG

User · Answer

You can try SDWebImage  it provides    Asynchronous loading Caching for offline use Place holder image to appear while loading Works well with UITableView   Quick example        cell imageView setImageWithURL  NSURL URLWithString   http   www domain com path to image jpg   placeholderImage  UIImage imageNamed   placeholder png

User · Answer

get DLImageLoader and try folowing code      DLImageLoader loadImageFromURL imageURL                           completed   NSError  error  NSData  imgData                                  imageView image    UIImage imageWithData imgData                                  imageView setContentMode UIViewContentModeCenter                                      Another typical real-world example of using DLImageLoader  which may help someone     PFObject  aFacebookUser    self fbFriends objectAtIndex thisRow   NSString  facebookImageURL    NSString stringWithFormat        http   graph facebook com    picture type large        aFacebookUser objectForKey   id         weak UIImageView  loadMe   self userSmallAvatarImage       note   you my  but usually DO NOT  want a weak ref  DLImageLoader loadImageFromURL facebookImageURL    completed   NSError  error  NSData  imgData            if   loadMe    nil   return       if  error    nil                    UIImage  image    UIImage imageWithData imgData           image    image ourImageScaler           loadMe image   image                else                      an error when loading the image from the net                     As I mention above another great library to consider these days is Haneke  unfortunately it s not as lightweight

User · Answer

Local URL s are super simple  just use this   UIImage contentsOfFile  url path

User · Answer

And the swift version       let url   NSURL URLWithString  http   live-wallpaper net iphone img app i p iphone-4s-wallpapers-mobile-backgrounds-dark 2466f886de3472ef1fa968033f1da3e1 raw 1087fae1932cec8837695934b7eb1250 raw jpg        var err  NSError      var imageData  NSData   NSData dataWithContentsOfURL url options  NSDataReadingOptions DataReadingMappedIfSafe  error   amp err      var bgImage   UIImage data imageData

User · Answer

The Best and easy way to load Image via Url is by this Code   dispatch async dispatch get global queue DISPATCH QUEUE PRIORITY DEFAULT  0          NSData  data   NSData dataWithContentsOfURL  NSURL URLWithString imgUrl         dispatch async dispatch get main queue               imgView image   UIImage imageWithData data                 Replace imgUrl by your ImageURL Replace imgView by your UIImageView   It will load the Image in another Thread  so It will not slow down your App load

User · Answer

Try this code  you can set loading image with it  so the users knows that your app is loading an image from url   UIImageView  yourImageView     UIImageView alloc  initWithImage  UIImage imageNamed   loading png          yourImageView setContentMode UIViewContentModeScaleAspectFit          Request image data from the URL      dispatch async dispatch get global queue DISPATCH QUEUE PRIORITY DEFAULT  0              NSData  imgData    NSData dataWithContentsOfURL  NSURL URLWithString   http   yourdomain com yourimg png              dispatch async dispatch get main queue                   if  imgData                                  Load the data into an UIImage                  UIImage  image    UIImage imageWithData imgData                      Check if your image loaded successfully                  if  image                                        yourImageView image   image                                    else                                         Failed to load the data into an UIImage                      yourImageView image    UIImage imageNamed   no-data-image png                                                else                                 Failed to get the image data                  yourImageView image    UIImage imageNamed   no-data-image png

User · Answer

Make sure enable this settings from iOS 9   App Transport Security Settings in Info plist to ensure loading image from URL so that it will allow download image and set it     And write this code   NSURL  url     NSURL alloc initWithString   http   feelgrafix com data images images-1 jpg    NSData  data   NSData dataWithContentsOfURL url   quickViewImage image    UIImage imageWithData data

User · Answer

The way using a Swift Extension to UIImageView  source code here    Creating Computed Property for Associated UIActivityIndicatorView  import Foundation import UIKit import ObjectiveC  private var activityIndicatorAssociationKey  UInt8   0  extension UIImageView         Associated Object as Computed Property     var activityIndicator  UIActivityIndicatorView            get               return objc getAssociatedObject self   amp activityIndicatorAssociationKey  as  UIActivityIndicatorView                   set newValue                objc setAssociatedObject self   amp activityIndicatorAssociationKey  newValue  UInt OBJC ASSOCIATION RETAIN                        private func ensureActivityIndicatorIsAnimating             if  self activityIndicator    nil                self activityIndicator   UIActivityIndicatorView activityIndicatorStyle  UIActivityIndicatorViewStyle Gray              self activityIndicator hidesWhenStopped   true             let size   self frame size              self activityIndicator center   CGPoint x  size width 2  y  size height 2               NSOperationQueue mainQueue   addOperationWithBlock      - gt  Void in                 self addSubview self activityIndicator                  self activityIndicator startAnimating                                    Custom Initializer and Setter      convenience init URL  NSURL  errorImage  UIImage    nil            self init           self setImageFromURL URL             func setImageFromURL URL  NSURL  errorImage  UIImage    nil            self ensureActivityIndicatorIsAnimating           let downloadTask   NSURLSession sharedSession   dataTaskWithURL URL    data  response  error  in             if  error    nil                    NSOperationQueue mainQueue   addOperationWithBlock      - gt  Void in                     self activityIndicator stopAnimating                       self image   UIImage data  data                                               else                   self image   errorImage                                 downloadTask resume

User · Answer

AFNetworking provides async image loading into a UIImageView with placeholder support  It also supports async networking for working with APIs in general

User · Answer

If you re really  absolutely positively sure that the NSURL is a file url  i e   url isFileURL  is guaranteed to return true in your case  then you can simply use     UIImage imageWithContentsOfFile url path

User · Answer

You can do it this way  synchronously  but compact    UIImage  image    UIImage imageWithData  NSData dataWithContentsOfURL  NSURL URLWithString MyURL       A much better approach is to use Apple s LazyTableImages to preserve interactivity

User · Answer

Check out the AsyncImageView provided over here   Some good example code  and might even be usable right  out of the box  for you

[ios] Can I load a UIImage from a URL?

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