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Before somebody says something about this topic being duplicated several times, please note that I really don't need loading remote images from the web (SDWebImage github solution), I'm trying to load images dynamically saved on the documents folder, so they are local by the time I want to load them on my tableView having reference to them via a record on a sqlite table in which I saved the image name as it was generated by code.

So after parsing all my sqlite data, in my CellForRowAtIndexPath method at a certain point I have the following lines of code:

-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    ...
    NSString *imageName = [[favorites objectAtIndex:[indexPath row]] objectForKey:@"imagename"];
    cell.image.image = [self loadImage: imageName]; // Is a custom cell so cell.image is a UIImageView, and I'm setting its image property
    ...
}

And my loadImage method looks like:

- (UIImage*)loadImage:(NSString*)imageName {

    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);

    NSString *documentsDirectory = [paths objectAtIndex:0];

    NSString *fullPath = [documentsDirectory stringByAppendingPathComponent:[NSString stringWithFormat:@"%@.png", imageName]];

    return [UIImage imageWithContentsOfFile:fullPath];

}

Note also that this code actually works but scrolling down the table looks laggy. How can I improve the performance, I mean loading images in the background comes to my mind but the images are already there. Can someone give me a concrete solution on this please?

Just to let you know, I'm working with iOS 5 and ARC.

Any help would be very appreciated.

Renexandro
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  • What size are the images you're trying to load? Large Retina images can be impossible to load and display in real time (i.e. in less than 1/60th second for smooth scrolling). You should minimize the image file size (go for highly compressed JPEG if you can), and you can also try to load and force the decompression of the image in the background (since UIKit only decompresses just before drawing), but memory might become a problem then. See [here](http://ioscodesnippet.tumblr.com/post/10924101444/force-decompressing-uiimage-in-background-to-achieve) for instance. – Guillaume Jul 11 '12 at 19:06
  • Ok I just read the link you posted but I don't understand how can I do that in the background for tableviews. I mean, should I use something like cell.image.image = perform in background bla bla but during scrolling this images will appear in the proper place or the cell instance will overlap and load a previous image in the visible spot cell.image of the new row being showed or maybe the image will load but not refresh the row it was referring to. A bit confuse about all this. – Renexandro Jul 11 '12 at 19:49

1 Answers1

0

Firstly decrease the size of image you load.

Secondly try to use GCD to load image in tableView:cellForRowAtIndexPath:.

hrchen
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