Скачать или смотреть How to Prevent Flutter RefreshIndicator from Rebuilding ListView with New Data

Learn how to maintain your `ListView` position while using `Flutter's RefreshIndicator` with `StreamBuilder` when adding new items.
---
This video is based on the question https://stackoverflow.com/q/68704452/ asked by the user 'luxury' ( https://stackoverflow.com/u/1837100/ ) and on the answer https://stackoverflow.com/a/68704498/ provided by the user 'luxury' ( https://stackoverflow.com/u/1837100/ ) 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: Flutter Refreshindicator rebuilding Listview.Builder after adding new items with StreamBuilder

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.
---
Understanding the Problem: RefreshIndicator and ListView Builder

When developing applications with Flutter, you might encounter a common issue when using a RefreshIndicator in conjunction with a StreamBuilder. The problem arises when the RefreshIndicator rebuilds the ListView upon receiving new data from the stream. This leads to an unintended behavior where the list jumps back to the top, disrupting the user experience.

In this guide, we will delve into this problem and provide a straightforward solution to keep your ListView stable while new items are added.

The Core Issue

When you use a StreamBuilder to listen for data changes:

The ListView inside of your RefreshIndicator is rebuilt every time there’s new data.

This behavior forces the ListView to scroll to the top, which can be frustrating for users who expect to see newly added items at the bottom of the list.

Solution: Using GlobalKey with RefreshIndicator

The effective solution to this problem is to utilize a GlobalKey for the RefreshIndicator. A GlobalKey helps manage the state of your widget, which, in this case, prevents the RefreshIndicator from rebuilding its child every time new data is received.

Step-by-Step Implementation

Here’s how you can implement this solution:

Define a GlobalKey: Start by declaring a GlobalKey for your RefreshIndicator.

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

Modify your StreamBuilder: In the StreamBuilder, set the key property of the RefreshIndicator to the GlobalKey you just created.

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

Key Components of the Solution

GlobalKey: By passing the _refreshIndicatorKey to the RefreshIndicator, Flutter retains its state instead of rebuilding, stopping the list from jumping back to the top.

Stream Management: The StreamBuilder continues to effectively manage the stream of data while interacting smoothly with the RefreshIndicator.

Conclusion

By implementing the GlobalKey, you can ensure that your ListView contents behave as expected when using a RefreshIndicator with a StreamBuilder. This small adjustment significantly enhances the user experience by maintaining the list's state, making your app feel more polished and user-friendly.

Next time you're working with Flutter and encounter this issue, remember this simple solution, and your users will thank you for a seamless navigation experience!