GPImageView

GPImageView : UIImageView

Used for getting the image from server (URL), cache, activity indicator, default image concept and main important point is running on main thread and using runloops
more detail visit
http://iphonedevelopment.blogspot.in/2010/05/downloading-images-for-table-without.html

=======================================================

//
//  GPImageView.h
//
//  Created by Gaurav D. Sharma & Piyush Kashyap
//  Date 11/06/12.
//

#import <UIKit/UIKit.h>

@interface GPImageView : UIImageView
{
    NSMutableData *imageData;
   
    NSString *imageURL;
   
}
@property (nonatomic) BOOL isCacheImage, showActivityIndicator;

@property (nonatomic, strong) UIImage *defaultImage;

/* --- Img from URL --- */
- (NSString*)getUniquePath:(NSString*)urlStr;

- (void)setImageFromURL:(NSString*)url;

- (void)setImageFromURL:(NSString*)url
  showActivityIndicator:(BOOL)isActivityIndicator
          setCacheImage:(BOOL)cacheImage;

@end

=======================================================

//
//  GPImageView.m
//
//  Created by Gaurav D. Sharma & Piyush Kashyap
//  Date 11/06/12.
//

#import "GPImageView.h"
#define TMP NSTemporaryDirectory()

@implementation GPImageView

@synthesize isCacheImage, showActivityIndicator;

@synthesize defaultImage;

- (NSString*)getUniquePath:(NSString*)  urlStr
{
    NSMutableString *tempImgUrlStr = [NSMutableString stringWithString:[urlStr substringFromIndex:7]];
   
    [tempImgUrlStr replaceOccurrencesOfString:@"/" withString:@"-" options:NSCaseInsensitiveSearch range:NSMakeRange(0, [tempImgUrlStr length])];
   
    // Generate a unique path to a resource representing the image you want
    NSString *filename = [NSString stringWithFormat:@"%@",tempImgUrlStr] ;  
   
    // [[something unique, perhaps the image name]];
    NSString *uniquePath = [TMP stringByAppendingPathComponent: filename];
   
    return uniquePath;
}

- (void)setImageFromURL:(NSString*)url
{
    [self setImageFromURL:url
    showActivityIndicator:showActivityIndicator
            setCacheImage:isCacheImage];
}


- (void)setImageFromURL:(NSString*)url
  showActivityIndicator:(BOOL)isActivityIndicator
          setCacheImage:(BOOL)cacheImage
{
   
    imageURL = [self getUniquePath:url];
   
    showActivityIndicator = isActivityIndicator;
   
    isCacheImage = cacheImage;
   
    if (isCacheImage && [[NSFileManager defaultManager] fileExistsAtPath:imageURL])
    {
        /* --- Set Cached Image --- */
        imageData = [[NSMutableData alloc] initWithContentsOfFile:imageURL];
       
        [self setImage:[[UIImage alloc] initWithData:imageData]];
       
    }
    /* --- Download Image from URL --- */
    else
    {
        if (showActivityIndicator) {
           
            UIActivityIndicatorView *activityIndicator = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleGray];
           
            activityIndicator.tag = 786;
           
            [activityIndicator startAnimating];
           
            [activityIndicator setHidesWhenStopped:YES];
           
            CGRect myRect = self.frame;
           
            CGRect newRect = CGRectMake(myRect.size.width/2 -12.5f,myRect.size.height/2 - 12.5f, 25, 25);
           
            [activityIndicator setFrame:newRect];
           
            [self addSubview:activityIndicator];
           
        }
       
        /* --- set Default image Until Image will not load --- */
        if (defaultImage) {
            [self setImage:defaultImage];
        }
       
        /* --- Switch to main thread If not in main thread URLConnection wont work --- */
        dispatch_async(dispatch_get_main_queue(), ^{
           
            imageURL = url;
           
            NSURLRequest *req = [[NSURLRequest alloc] initWithURL:[NSURL URLWithString:url]];
           
            NSURLConnection *con = [[NSURLConnection alloc] initWithRequest:req
                                                                   delegate:self
                                                           startImmediately:NO];
           
            [con scheduleInRunLoop:[NSRunLoop currentRunLoop]
                           forMode:NSRunLoopCommonModes];
           
            [con start];
           
            if (con) {
                imageData = [NSMutableData new];
            }  
            else {
                NSLog(@"GPImageView Image Connection is NULL");
            }
        });
    }
   
}

#pragma mark - NSURLConnection delegate
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{
    [imageData setLength:0];
}
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{
    [imageData appendData:data];
}

- (void)connection:(NSURLConnection *)connection
  didFailWithError:(NSError *)error
{
    NSLog(@"Error downloading");
   
[self setImage:defaultImage];
  
    /* --- hide activity indicator --- */
    if (showActivityIndicator)
    {
        UIActivityIndicatorView *activityIndicator = (UIActivityIndicatorView*)[self viewWithTag:786];
      
        [activityIndicator stopAnimating];
      
        [activityIndicator removeFromSuperview];
    }

    imageData = nil;
}

- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
    /* --- hide activity indicator --- */
    if (showActivityIndicator)
    {
        UIActivityIndicatorView *activityIndicator = (UIActivityIndicatorView*)[self viewWithTag:786];
       
        [activityIndicator stopAnimating];
       
        [activityIndicator removeFromSuperview];
    }
   
    /* --- set Image Data --- */
    [self setImage:[UIImage imageWithData:imageData]];
   
    /* --- Get Cache Image --- */
    if (isCacheImage) {
        [imageData writeToFile:[self getUniquePath:imageURL]
                    atomically:YES];
    }
   
    imageData = nil;
   
}                          

@end