Call it Images and add two attributes : image - Binary Data and index - type integer Turn now back to the ViewController class. We'll define the functions that download the JSON data in an asynchronous way, extract the JSON data, fill the array with the data and refresh the table.
After the JSON data are extracted, the read function is called. This function will be implemented in the next step and will read from the Core Data entity the stored data and will fill the TableData array with the cached images data. Let's now define the function that will download the image from url , update the TableData local cache for that session , update the Core data for the permanent cache and finally update the UITableViewCell image. Let's now define the functions that will read and store the data in core data.
Be sure to import the CoreData library. NSData TableData[index]. The save function will store image in core data.
Download the example. If you enjoyed this tutorial, share it. You can fine more Swift tutorial here. For any question, be free to write a comment below. About Contact. KaleidosBlog TechnoVision. Swift cache: how to download and cache data in iOS You'll learn how to cache data in swift by developing a local cache based on core data for the downloaded data.
Coding Part For the Json data I've prepared for you a simple data structure. Open now the ViewController and let's define the required variables. Define the Core Data Entity Let's now define the Core data entity that will store the images in a permanent way. Leave a comment.
Prunus - 06 April at Hi Great tutotial. David - 29 June at Hi Thanks for the great tutorial. I'm wondering where do you set the exact position of the image and the label? Andrea - 29 June at Hi, in this tutorial I've used the default iOS table cell, that containts the image and the label in that default position. However you can define your custom cell.
Zak - 29 April at Hi Andrea, great tutorial, it is really helpful tutorials like this one, I have a question, how to make this app work offline, always using core data? You should at least know about UIImage and what a dictionary or hash is.
So for caching, all you need to do is make sure you have imported UIKit. Then make an instance of NSCache.
There are two ways you can do it. Up to you. I will do it the way I usually do. After we create an instance of NSCache we will put the image in cache. But if you are not using NSCache, you can just do this wherever your image is set.
So if you set your UIImage. See Image and Graphics Best Practices to learn more about image decoding and downsampling. At the core of Nuke is the ImagePipeline class. Use the pipeline directly to load images without displaying them:. To download the data without doing any expensive decoding or processing, use loadData with:progress:completion:.
When you start the request, the pipeline returns an ImageTask object, which can be used for cancelation and more.
If you want to build a system that fits your specific needs, you won't be disappointed. There are a lot of things to tweak. You can set custom data loaders and caches, configure image encoders and decoders, change the number of concurrent operations for each individual stage, disable and enable features like deduplication and rate limiting, and more. To learn more see the inline documentation for ImagePipeline. Configuration and Image Pipeline Overview.
The entire configuration is described by the ImagePipeline. Configuration struct. To create a pipeline with a custom configuration either call the ImagePipeline configuration: initializer or use the convenience one:.
ImageCache uses the LRU algorithm — least recently used entries are removed first during the sweep. You can enable it using the pipeline configuration. By default, the pipeline stores only the original image data. To store downloaded and processed images instead, set dataCacheOptions. This option is useful if you want to store processed, e.
To save disk space see ImageEncoders. ImageIO and a new experimental ImageEncoder. Keep in mind that prefetching takes up users' data and puts extra pressure on CPU and memory. To reduce the CPU and memory usage, you have an option to choose only the disk cache as a prefetching destination:. To enable progressive image decoding set isProgressiveDecodingEnabled configuration option to true.
And that's it, the pipeline will automatically do the right thing and deliver the progressive scans via progress closure as they arrive:. To enable animated image support, set ImagePipeline. If enabled, Nuke will attach animatedImageData to the downloaded animated images.
You going to need data to render the images. Option 1. Option 2. Install Gifu directly. To configure Gifu to work with Nuke, all you need to do is add these lines in your project:. GIF is not the most efficient format for transferring and displaying animated images. The current best practice is to use short videos instead of GIFs e.
MP4 , WebM. There is a PoC available in the demo project which uses Nuke to load, cache and display an MP4 video. Please follow the instructions from the repo. Niklas Niklas 1, 12 12 silver badges 11 11 bronze badges. Garrett Cox Garrett Cox 6 6 silver badges 10 10 bronze badges. Hi Garrett, I have used kingfisher for my other projects. But the problem is I can't use KF for this task out of the box. I have to tweak the way I download the images using KF.
Also please let me know how you downloaded images from S3 using KF. Did you just use the KF's cache for downloaded images or were you able to send authentication headers using KF or is there any method which you followed :.
This would help me a great deal. Thanks — iamyogish. This was because I made my images public. I understand that that is not a possibility for all cases. Sign up or log in Sign up using Google. Sign up using Facebook.
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