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Learn how to keep your off-screen `GridView` widgets alive and avoid them being destroyed when you scroll through your Flutter app.
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Keeping Your Flutter GridView Widgets Intact on Scroll

If you are a Flutter developer using a GridView in your app, you may have encountered a frustrating issue: Off-screen widgets, particularly custom cards with images and text, get destroyed when you scroll. This can result in poor user experience, especially if your grid is composed of widgets that need to maintain their state or previously loaded images. Fortunately, there are effective solutions to this problem—the key lies in understanding a few properties that can help retain your off-screen widgets. Let’s explore how you can resolve this issue through a step-by-step guide.

Understanding the Problem

When using a GridView in Flutter, it only retains the widgets that are currently visible on the screen. This is done to conserve memory and improve performance. However, once you scroll away from those widgets, they can be completely destroyed, leading to delays and flickers when they need to be brought back into view. This is particularly cumbersome if your widgets are complex and require time-consuming operations like image loading.

Solution: Keeping Off-Screen Widgets Alive

To solve this issue, you can utilize two key properties of the GridView: addAutomaticKeepAlives and cacheExtent. Let’s break down how these properties work and how to implement them effectively.

1. Understanding addAutomaticKeepAlives

The addAutomaticKeepAlives property determines whether the scrollable will automatically keep its children alive when they are scrolled off-screen. By default, addAutomaticKeepAlives is set to true, meaning that the widgets shouldn't be destroyed off-screen. However, always ensure that it’s explicitly set just to be safe.

2. Configuring cacheExtent

The cacheExtent property allows you to specify how much area before and after the visible region (viewport) should maintain its children in memory. By providing a DOUBLE VALUE, you can expand the extent of cached widgets, thereby preventing them from being destroyed when they scroll out of sight.

Example Code

Here's a simple example to illustrate how to adjust these properties in your GridView:

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

3. Adjusting Cache Extent as Needed

Experiment: The value set for cacheExtent can vary based on the complexity of your widgets and how much content they hold. You might need to run some tests to find the sweet spot between memory usage and performance.

Monitor: Keep an eye on memory usage in Flutter's performance tools to avoid excessive resource consumption.

Conclusion

Holding onto off-screen widgets in a GridView is essential for creating a smooth user experience in your Flutter applications. By effectively leveraging addAutomaticKeepAlives and tweaking the cacheExtent, you can ensure that your custom cards and their corresponding data remain readily accessible, drastically improving performance and responsiveness when users scroll through your app.

Make sure to apply these tips and enjoy a seamless user experience in your Flutter projects!