CODEWITHSUNDEEP
iosobjective-curlcaching
maxisme
maxisme

Reputation: 4265

How to cache images ios

I currently have an array with lots of image URLs called images They are being put into my table like this:

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *simpleTableIdentifier = @"SimpleTableCell";

    SimpleTableCell *cell = (SimpleTableCell *)[tableView dequeueReusableCellWithIdentifier:simpleTableIdentifier];
    if (cell == nil)
    {
        NSArray *nib = [[NSBundle mainBundle] loadNibNamed:@"SimpleTableCell" owner:self options:nil];
        cell = [nib objectAtIndex:0];
    }

    NSLog(@"indexPath.row=%ld", (long)indexPath.row);
    NSLog(@"images[indexPath.row]=%@", [images objectAtIndex:indexPath.row]);

    NSString *stringy = @"http://www.tragicclothing.co.uk/";
    NSString *link = [stringy stringByAppendingString: images[indexPath.row]];
    NSString* encodedString = [link stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
    NSData * imageData = [[NSData alloc] initWithContentsOfURL: [NSURL URLWithString:encodedString]];
    cell.thumbnailImageView.image = [UIImage imageWithData: imageData];
    cell.backgroundColor = [UIColor clearColor];
    cell.opaque = NO;
    cell.backgroundView = nil;

    return cell;
}

But this is causing a lot of lag when scrolling. How could I cache the data? to prevent this lag? I have seen SDWebImage but I don't quite know how to use it! It seems very complicated.

Should I be using

SDImageCache *imageCache = [[SDImageCache alloc] initWithNamespace:@"myNamespace"];
[imageCache queryDiskCacheForKey:myCacheKey done:^(UIImage *image)
{
    // image is not nil if image was found
}];

Upvotes: 0

Views: 4169

Answers (2)

meda
meda

Reputation: 45500

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *simpleTableIdentifier = @"SimpleTableCell";

    SimpleTableCell *cell = (SimpleTableCell *)[tableView dequeueReusableCellWithIdentifier:simpleTableIdentifier];
    if (cell == nil)
    {
        NSArray *nib = [[NSBundle mainBundle] loadNibNamed:@"SimpleTableCell" owner:self options:nil];
        cell = [nib objectAtIndex:0];
    }

    NSLog(@"indexPath.row=%ld", (long)indexPath.row);
    NSLog(@"images[indexPath.row + 7]=%@", [images objectAtIndex:indexPath.row + 7]);


    NSString *stringy = @"http://www.tragicclothing.co.uk/";
    NSString *link = [stringy stringByAppendingString: images[indexPath.row + 7]];
    NSString* encodedString = [link stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
    [cell.thumbnailImageView setImageWithURL:[NSURL URLWithString:encodedString] placeholderImage:[UIImage imageNamed:@"Comp 2_00000.png"]];
    cell.backgroundColor = [UIColor clearColor];
    cell.opaque = NO;
    cell.backgroundView = nil;


    return cell;
}

Upvotes: 1

Pawan Rai
Pawan Rai

Reputation: 3444

nothing can be simple then SDWebImage

it prodide the following solution

An UIImageView category adding web image and cache management to the Cocoa Touch framework

An asynchronous image downloader

An asynchronous memory + disk image caching with automatic cache expiration handling

#import <SDWebImage/UIImageView+WebCache.h>

NSString* encodedString = [link stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];

[cell.thumbnailImageView setImageWithURL:[NSURL URLWithString:encodedString]
               placeholderImage:[UIImage imageNamed:@"placeholder.png"]];

Upvotes: 1

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