Solving the MarkerComposable Rerendering Issue in Google Maps with Jetpack Compose

Описание: Discover how to resolve the `MarkerComposable` recomposing issue in Google Maps using Jetpack Compose, enhancing your app's interactivity with custom marker animations.
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This video is based on the question https://stackoverflow.com/q/78202197/ asked by the user 'Jose' ( https://stackoverflow.com/u/23714909/ ) and on the answer https://stackoverflow.com/a/78207305/ provided by the user 'Samuel Otis' ( https://stackoverflow.com/u/7422588/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Tackling the MarkerComposable Rerendering Issue in Google Maps

Creating interactive applications can sometimes lead developers down complicated paths, especially when dealing with UI components like maps. If you've encountered issues with the MarkerComposable in Jetpack Compose not re-rendering correctly when an icon is clicked, you're not alone. This guide addresses the problem of marker interactions and provides a straightforward solution.

Understanding the Problem

When working with custom markers in Google Maps through Jetpack Compose, some developers aim to create engaging animations for their markers. For instance, expanding or changing a marker's icon when clicked can enhance user experience. However, it can become frustrating when the marker doesn't seem to respond to clicks as expected. Specifically, you might find that while the MarkerComposable itself gets recomposed, the associated Image does not change upon clicking the marker.

The Challenge

Symptom of the Problem: Clicking a marker does not alter the visual representation of its icon.

Investigation: Attempts to utilize both image swapping and modifiers yield no visual changes, leading to further bewilderment.

Lack of Documentation: Limited resources or support surrounding MarkerComposable complications add to the difficulty in resolving the issue.

The Solution: Using the Keys Parameter

After investigating this issue, the solution becomes clear: it involves utilizing the keys parameter within the MarkerComposable. Adjusting this parameter ensures that the marker is properly rerendered when its state changes.

Implementation Steps

Identify the Trigger for Rerendering:

When you click the marker, its state should change, and the UI should reflect this change.

Modify the MarkerComposable as follows:
To see changes in the icon when clicked, specify the keys parameter in your MarkerComposable. Here’s how you structure your code:

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

Summary of Changes

Key Parameter: You must set the keys parameter to a variable that changes when the marker is clicked. In this case, the iconSelected state variable fulfills that role.

Effect: This small adjustment ensures both the MarkerComposable and the Image inside it are appropriately recomposed, leading to the desired animation effect when the marker is clicked.

Conclusion

By implementing the above solution, you can easily address the MarkerComposable rerendering issue within your Jetpack Compose application. The key takeaway is the importance of using the keys parameter to ensure state changes trigger the necessary UI updates.

Now, you are equipped with the knowledge to enhance the interactivity of your map markers, making your app more engaging and user-friendly. Happy coding!