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Learn how to effectively implement a `placeholder` in CachedNetworkImage while loading images in Flutter. Here you'll find a step-by-step guide to ensure a smooth user experience.
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How to Use Placeholder in CachedNetworkImage in Flutter

When developing mobile applications with Flutter, loading images from the internet can sometimes be a challenging task, especially when it comes to handling image loading states. A common requirement is to provide users with visual feedback while an image is downloading. In this guide, we will dive into how to efficiently use a placeholder in the CachedNetworkImage widget to show a loading indicator until the image is fully loaded.

Understanding the Problem

You might have encountered a situation where you are implementing the CachedNetworkImage widget, and you want to show a loading indicator, such as a progress bar, while the image is being fetched. For instance, you might have initially attempted to use the placeholder parameter directly with something like this:

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

However, it doesn’t provide the expected result. In this post, we will explore the correct way to achieve this using the progressIndicatorBuilder and placeholder properties effectively.

Solution: Using CachedNetworkImage Properly

To properly display a loading indicator while the image is still being downloaded, you have a couple of options. Below, we break down the techniques you can use.

Option 1: Using progressIndicatorBuilder

The progressIndicatorBuilder is a specific builder designed to show a loading state with information about the download progress. Here’s how you can implement it:

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

Key Points:

The progressIndicatorBuilder takes a function that gives you access to the download progress. This can be visually represented in your loader.

The CircularProgressIndicator can be customized to show the actual progress of the image being downloaded.

Option 2: Using placeholder for a Simple Loading Indicator

Alternatively, if you want a simpler approach without the progress detail, you can define a placeholder like this:

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

Key Points:

The placeholder is a simpler way to indicate that the image is loading, without indicating progress.

This approach is ideal if you want a straightforward loading experience without additional complexity.

Conclusion

Implementing a placeholder in CachedNetworkImage is essential for enhancing user experience in your Flutter applications. By using either the progressIndicatorBuilder for detailed progress feedback or the placeholder for a simple loading spinner, you can ensure that users are informed about the image loading process.

Remember, providing visual feedback is critical to keeping users engaged while images are being loaded over the network. So, next time you are implementing image loading, consider using these techniques to improve your app's UX.

If you have any more questions or need further clarification on how to implement this in your application, feel free to reach out in the comments!