The phrase “lazy loading” is used to describe the act of downloading pictures in layman’s terms. As a result, the software does not become unresponsive as images are downloaded.
However, from a technological standpoint, it is the ability to define the default procedures that are compiled and loaded into memory when a program is launched. Lazy loading is designed to speed up the startup time of an application by eliminating unused capabilities.
Lazy loading is also known as “dynamic function loading”.
If the page requires a large number of static images, this will have little impact on an application’s performance since those pictures are kept locally on the device. When we need to load photos remotely, however, there is a danger that they won’t load appropriately and that the user will become irritated while waiting for them to appear.
Lazy loading offers a quick solution for remote loading of images and helps you to provide better performance to the user. When you use it, the images are loaded in an asynchronous manner. What this can do is show some default images to the user and load the images remotely. This will not negatively affect the performance of the app.
The user will be able to see the information rather than having to wait for the pictures to load with a lazy loading design in place. It may be used on various platforms, but I’ll explain how it works in iOS in this post.
It’s possible to use a library or not to use one. So I’ll start with the first option, which is a simple and easy approach to implement lazy image loading in the table view.
#import <SDWebImage/UIImageView+WebCache.h> //1
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
// 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"]]; //2
By adding the above changes to your code, you will really see great performance from the application and your users will not feel frustrated. This works really well for most of the apps where we deal with images loading remotely.
It is feasible to write customized code if you do not wish to utilize an external library, but keep in mind that we have a limit on the number of pictures that may be downloaded remotely each time. Consider that you have 1,000 photographs to download but that you are limited to a certain number (for example, 10 or other) so that it may only grab 10 images at once instead of 1000. It’s possible that the table view has visible rows. To know how to download image asynchronously using a number limit you can refer to https://developer.apple.com/library/ios/samplecode/LazyTableImages/Introduction/Intro.html
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