TableView Images仅在向下滚动时显示

Question

I am loading a tableview with images. These are loaded asynchronously. The images only get displayed with i scroll the tableview.

I know this happens because of the reusable cells inside the tableview. My code is as follows.

How can i prevent this.

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    MyCell *c = [tableView dequeueReusableCellWithIdentifier:@"cell"];

    if (c == nil)

    {

        c = [[MyCell alloc] initWithStyle:UITableViewCellStyleSubtitle

                                      reuseIdentifier:@"cell"];

    }



    NSURL *url = [NSURL URLWithString:@"http://www.ss.com/my.png"];

    NSURLRequest *r = [NSURLRequest requestWithURL:url];

    [c.myImageView setImageWithURLRequest:r placeholderImage:[UIImage imageNamed:@"def.png"] success:^(NSURLRequest *request,   NSHTTPURLResponse *response, UIImage *image) {

        if (c)

        {

            c. myImageView.image = image;

            [c setNeedsLayout];

        }

    } failure:^(NSURLRequest *request, NSHTTPURLResponse *response, NSError *error) {

        NSLog(@"Error: %@", error);

    }];

Answer 1

In this case use lazy loading technique. As if we have to show the images in table view lazy loading is best technique. here is the library https://github.com/rs/SDWebImage Just add the SDWebImage folder in your project. Then in your class import the following

#import "UIImageView+WebCache.h"

and in cellforRowIndex method write the following code

 NSURL *url = [NSURL URLWithString:@"http://www.ss.com/my.png"];
[c.myImageView setImageWithURL:url placeholderImage:[UIImage imageNamed:@"def.png"]];

No need for success failure block as it will lazy load images and will keep them in cache by making as a key itself. So if the image is already loaded once then next time when you will open this controller, it will show up as if was in your local storage. Thats the benefit of this library