iOS: Download image from url and save in device

Question

I am trying to download the image from the url http://a3.twimg.com/profile_images/414797877/05052008321_bigger.jpg

I am using the following code, but image is not saved in the device. I want to know what I am doing wrong.

 NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:@"http://a3.twimg.com/profile_images/414797877/05052008321_bigger.jpg"]];  [NSURLConnection connectionWithRequest:request delegate:self];   NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);  NSString *documentsDirectory = [paths objectAtIndex:0];  NSString *localFilePath = [documentsDirectory stringByAppendingPathComponent:@"pkm.jpg"];  NSData *thedata = NULL;  [thedata writeToFile:localFilePath atomically:YES];   UIImage *img = [[UIImage alloc] initWithData:thedata]; 

Answer 1

I happen to have exactly what you are looking for.

Get Image From URL

-(UIImage *) getImageFromURL:(NSString *)fileURL {     UIImage * result;      NSData * data = [NSData dataWithContentsOfURL:[NSURL URLWithString:fileURL]];     result = [UIImage imageWithData:data];      return result; } 

Save Image

-(void) saveImage:(UIImage *)image withFileName:(NSString *)imageName ofType:(NSString *)extension inDirectory:(NSString *)directoryPath {     if ([[extension lowercaseString] isEqualToString:@"png"]) {         [UIImagePNGRepresentation(image) writeToFile:[directoryPath stringByAppendingPathComponent:[NSString stringWithFormat:@"%@.%@", imageName, @"png"]] options:NSAtomicWrite error:nil];     } else if ([[extension lowercaseString] isEqualToString:@"jpg"] || [[extension lowercaseString] isEqualToString:@"jpeg"]) {         [UIImageJPEGRepresentation(image, 1.0) writeToFile:[directoryPath stringByAppendingPathComponent:[NSString stringWithFormat:@"%@.%@", imageName, @"jpg"]] options:NSAtomicWrite error:nil];     } else {         NSLog(@"Image Save Failed\nExtension: (%@) is not recognized, use (PNG/JPG)", extension);     } } 

Load Image

-(UIImage *) loadImage:(NSString *)fileName ofType:(NSString *)extension inDirectory:(NSString *)directoryPath {     UIImage * result = [UIImage imageWithContentsOfFile:[NSString stringWithFormat:@"%@/%@.%@", directoryPath, fileName, extension]];      return result; } 

How-To

//Definitions NSString * documentsDirectoryPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];  //Get Image From URL UIImage * imageFromURL = [self getImageFromURL:@"http://www.yourdomain.com/yourImage.png"];  //Save Image to Directory [self saveImage:imageFromURL withFileName:@"My Image" ofType:@"png" inDirectory:documentsDirectoryPath];  //Load Image From Directory UIImage * imageFromWeb = [self loadImage:@"My Image" ofType:@"png" inDirectory:documentsDirectoryPath]; 

Answer 2

If you set theData to nil, what do you expect it to write to the disk?

What you can use is NSData* theData = [NSData dataWithContentsOfURL:yourURLHere]; to load the data from the disk and then save it using writeToFile:atomically:. If you need more control over the loading process or have it in background, look at the documentation of NSURLConnection and the associated guide.