Download image asynchronously

Question

I need to download an image from the web and display it in an ImageView. Presently I am using SDWebImage (It is an asynchronous image downloader wi

Answer 1

//JImage.h

#import 


@interface JImage : UIImageView {

    NSURLConnection *connection;

    NSMutableData* data;

    UIActivityIndicatorView *ai;
}

-(void)initWithImageAtURL:(NSURL*)url;  

@property (nonatomic, retain) NSURLConnection *connection;

@property (nonatomic, retain) NSMutableData* data;

@property (nonatomic, retain) UIActivityIndicatorView *ai;

@end



//JImage.m

#import "JImage.h"

@implementation JImage
@synthesize ai,connection, data;

-(void)initWithImageAtURL:(NSURL*)url {


    [UIApplication sharedApplication].networkActivityIndicatorVisible = YES;

    [self setContentMode:UIViewContentModeScaleToFill];

    if (!ai){

        [self setAi:[[UIActivityIndicatorView alloc]   initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhiteLarge]]; 

        [ai startAnimating];

        [ai setFrame:CGRectMake(27.5, 27.5, 20, 20)];

        [ai setColor:[UIColor blackColor]];

        [self addSubview:ai];
    }
    NSURLRequest* request = [NSURLRequest requestWithURL:url cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:60];

    connection = [[NSURLConnection alloc] initWithRequest:request delegate:self];    
}


- (void)connection:(NSURLConnection *)theConnection didReceiveData:(NSData *)incrementalData {

if (data==nil) data = [[NSMutableData alloc] initWithCapacity:5000];

[data appendData:incrementalData];

NSNumber *resourceLength = [NSNumber numberWithUnsignedInteger:[data length]];

NSLog(@"resourceData length: %d", [resourceLength intValue]);

}
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error 
{
    NSLog(@"Connection error...");

    [UIApplication sharedApplication].networkActivityIndicatorVisible = NO;

    [ai removeFromSuperview];

}
- (void)connectionDidFinishLoading:(NSURLConnection*)theConnection 
{
    [UIApplication sharedApplication].networkActivityIndicatorVisible = NO;

    [self setImage:[UIImage imageWithData: data]];

    [ai removeFromSuperview];   
}
@end



//Include the definition in your class where you want to use the image
-(UIImageView*)downloadImage:(NSURL*)url:(CGRect)frame {

JImage *photoImage=[[JImage alloc] init]; 

    photoImage.backgroundColor = [UIColor clearColor]; 

   [photoImage setFrame:frame];

   [photoImage setContentMode:UIViewContentModeScaleToFill]; 

    [photoImage initWithImageAtURL:url];

    return photoImage;
}


//How to call the class

UIImageView *imagV=[self downloadImage:url :rect]; 

//you can call the downloadImage function in looping statement and subview the returned  imageview. 
//it will help you in lazy loading of images.


//Hope this will help