How to load tables of information faster using GCD

Question

Currently I am loading all of my UITableViewControllers with images and text. I'm not sure if there is a way of shortening my loading times. I'm thinking that GCD might be the best route to go, however, I'm not too sure that I'm using this correctly:

dispatch_async(dispatch_get_main_queue(), ^{

        [some method];

    });

This is being loaded in the ViewDidLoad, and I'm unsure if this is the correct place to use GCD. Also, is this correct way of asynchronously loading information?

your method is exactly correct and this is update UI Main thread Faster — codercat, Jan 27 '14 at 07:39
@iDev, Why do you think using GCD is faster in this situation? — Woodstock, Jan 27 '14 at 08:39
You should provide more info about you specific problem. Are you loading data from a remote server? — CouchDeveloper, Jan 27 '14 at 09:51

score 0 · Answer 1 · edited May 23 '17 at 12:03

0

use this, it downloads multiple files in different threads.And its asynchronous.

dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
        //load image here
    });

If you want to load all images ,even the images which might be very down in tableView (say image at 20th row).Then viewDidLoad is perfect approach, or if you want to only load images that are currently to be shown, then download images in cellForRow:atIndexPath method.

OR,you can use AFNetworking to download multiple files much efficiently.

Hope this helps

edited May 23 '17 at 12:03

Community

1
1

answered Jan 27 '14 at 07:28

santhu

4,796
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Yeah, I've tried this in both the ViewDidLoad and cellForRow:atIndexPath, but they still load very slowly. I appreciate the help! – Fullmetal_Alchemist_Fan Jan 27 '14 at 07:52
@JohnSmith The answer as it stands now surely can't help: there's virtually no hint how you could improve your code. – CouchDeveloper Jan 27 '14 at 09:39

score 0 · Answer 2 · answered Jan 27 '14 at 09:46

For loading images faster in table view cells you can use SDWebImage.

It is very simple to use. Just import the SDWebImage folder into your Xcode project. It contains a category on UIImageVIew. So on any imageView object just call the method setImageWithURL as illustrated below:

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath

{

static NSString *MyIdentifier = @"MyIdentifier";

UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:MyIdentifier];

if (cell == nil)
{
    cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault
                                   reuseIdentifier:MyIdentifier] autorelease];
}

// Here we use the new provided setImageWithURL: method to load the web image
[cell.imageView setImageWithURL:[NSURL URLWithString:@"http://www.domain.com/path/to/image.jpg"]
               placeholderImage:[UIImage imageNamed:@"placeholder.png"]];

cell.textLabel.text = @"My Text";
return cell;

}

How to load tables of information faster using GCD

2 Answers2