Скачать или смотреть Efficiently Cache Images in ListView with Flutter and AppWrite

Discover how to efficiently cache images in Flutter's ListView using AppWrite to avoid redundant downloads. Learn the key techniques today!
---
This video is based on the question https://stackoverflow.com/q/73770036/ asked by the user 'pitcairn1987' ( https://stackoverflow.com/u/16175847/ ) and on the answer https://stackoverflow.com/a/73862205/ provided by the user 'Steven Nguyen' ( https://stackoverflow.com/u/8107901/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: Caching images (thumbnails) in Listview

Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l...
The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license.

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
Efficiently Cache Images in ListView with Flutter and AppWrite

When developing applications in Flutter, especially those that involve displaying a dynamic list of items with images, performance can become an issue. A common scenario is when using ListView.builder to display user images fetched from an API, such as AppWrite. After completing the initial setup and getting images to display, you might run into a challenge: how to prevent the entire list from refreshing and re-fetching images when an item is removed. In this guide, we'll explore a couple of different approaches to image caching in Flutter and help you choose the best one for your needs.

The Problem: Unwanted List Refresh

In your current setup, you are using FutureBuilder to create CircleAvatar widgets containing photos fetched via an API call. The challenge arises when you delete an item from the list. Consequently, the whole list refreshes, leading to redundant API calls and increased loading times for images.

Sample Code Setup

Here's the snippet where you build the image using a FutureBuilder:

[[See Video to Reveal this Text or Code Snippet]]

This implementation works fine initially, but it leads to the entire list being re-fetched every time an item is removed.

Solutions to Consider

Fortunately, there are multiple approaches to solve this issue, one of which you have already experimented with. Let's break them down:

1. Pre-fetching and Caching Images in Your Object

You've considered downloading images for each list item beforehand and storing them as Uint8List byte arrays within your object model. This way, each item already contains the necessary image data, eliminating the need to use FutureBuilder. This method could optimize your app's performance significantly.

Advantages:

Reduced API Calls: Once images are cached in your object model, no further API calls are made when items are removed or displayed.

Faster Access: Displaying images becomes instantaneous as the data is already present in memory.

Disadvantages:

Higher Initial Load Time: The initial fetching of images for all items may take more time, especially if you have a large dataset.

2. Using Cached Network Images

Another option is to use the cached_network_image package, which simplifies image caching like so:

Implementation Example:

To use this package, you can build the image URL manually:

[[See Video to Reveal this Text or Code Snippet]]

If your file isn't public, you'll also need to generate a JWT token and pass it in:

[[See Video to Reveal this Text or Code Snippet]]

Advantages:

Automatic Caching: This approach combines fetching and caching, streamlining your process without handling the bytes manually.

Easy to Use: The cached_network_image package handles cache management internally.

Disadvantages:

Dependency on Additional Libraries: Using extra packages may increase project complexity and size.

Conclusion: Finding Your Best Solution

Both solutions—pre-fetching images into your object model or utilizing a caching package—can effectively minimize redundant downloads and enhance user experience. The best choice largely depends on your specific requirements and user base. If you anticipate high traffic and data volume, leveraging a caching library could prove more efficient in the long run. However, if your app handles a manageable dataset, maintaining images in your model could yield faster results.

Whichever method you choose, implementing effective image caching is crucial for creating responsive and user-friendly applications in Flutter. Feel free to try both strategies and see which one aligns best with your development style and application needs!