Скачать или смотреть Solving the ReorderableList Dragging Issue in Flutter

Discover why your `ReorderableList` in Flutter isn't registering drag events and learn how to fix it using `ReorderableListView.builder`.
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This video is based on the question https://stackoverflow.com/q/73614099/ asked by the user 'Emil Walseth' ( https://stackoverflow.com/u/19898190/ ) and on the answer https://stackoverflow.com/a/73614358/ provided by the user 'Franz' ( https://stackoverflow.com/u/14729495/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Troubleshooting Flutter: Why Isn't My ReorderableList Registering Drags?

Flutter is an incredibly popular framework for building natively compiled applications for mobile, web, and desktop from a single codebase. However, even seasoned Flutter developers run into issues occasionally. A common problem that arises is when your ReorderableList widget isn't responding to drag events as expected. If you're experiencing this, you're not alone! Let’s dive into this common issue and explore a simple solution.

The Problem: ReorderableList Not Responding to Drags

Imagine you're building a simple chat application, and you've added a ReorderableList. You write the code, and to your surprise, you find that you can't drag your list tiles at all. Not only that, but the onReorder callback remains empty, leading to confusion. This situation can be frustrating, especially if you've set everything up correctly.

Here’s an example of what your ReorderableList might look like:

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Key Issues

Invisible Drag Handling: Sometimes, the UI is rendered but doesn't allow for any drag interactions.

Empty Callback: Leaving the onReorder callback empty could lead to further confusion as it gives the impression that the reorder functionality isn't working.

Solution: Switch to ReorderableListView.builder

To resolve the dragging issue, consider switching from ReorderableList to ReorderableListView.builder. This variant provides a more optimized way to manage your list items, especially when dealing with a larger number of items. Here’s how you can implement it:

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Why This Change Works

Improved Performance: The ReorderableListView.builder is designed to handle dynamic lists more efficiently.

Automatic Handling of Drag Gestures: This widget seamlessly manages drag-and-drop operations, ensuring that user interactions are recognized promptly.

Consistency with Flutter Conventions: Using builder methods aligns with Flutter's paradigm for building interfaces, which promotes better management of state and performance.

Conclusion

If your ReorderableList isn't registering drag events, shifting to ReorderableListView.builder is an effective solution. It not only resolves the immediate issue but also enhances the efficiency of your application. Flutter is all about creating smooth and responsive apps, and using the right widgets plays a crucial role in achieving that goal.

With these tips, you can make your Flutter app more interactive and user-friendly. Happy coding!