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Learn how to implement a checkbox selection mechanism in a Flutter ListView that allows only one answer to be chosen per question in a survey format.
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This video is based on the question https://stackoverflow.com/q/73862423/ asked by the user 'Quinn' ( https://stackoverflow.com/u/7546078/ ) and on the answer https://stackoverflow.com/a/73862516/ provided by the user 'Md. Yeasin Sheikh' ( https://stackoverflow.com/u/10157127/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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How to Select a Single Checkbox in a ListView within ListView in Flutter

Creating a survey application can be challenging when it comes to managing user input. One common requirement is to ensure that users can only select one answer per question from a list of options. In this blog, we'll explore how to achieve this using Flutter's ListView widget.

Understanding the Problem

When dealing with a survey format that contains multiple questions with several answer options, you might want to restrict the answer selection to allow only one checkbox to be selected for each question. This means that if a user selects one answer, any previously selected answer for that question should be automatically deselected.

We’ll dive into a concrete example to show how you can manage this behavior with Flutter. Here’s a simple structure of our survey data:

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

Solution Overview

To approach this problem, we can make use of a Map to store the selected answers for each question. This allows us to easily track the currently selected answer and implement the necessary logic to limit the user's selections.

Step 1: Define the Data Structure

We will create a Map<String, int> to hold the selected answers. The String key will represent the question, and the int value will represent the selected answer's ID.

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

Step 2: Create a Method to Check Selections

Next, we need a method that checks if a particular answer is currently selected:

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

This method will allow us to determine whether a checkbox should be checked based on the current answer ID.

Step 3: Update the Checkbox Selection Logic

Within your Checkbox widget, we can implement the logic to update the selected answer when a checkbox is pressed. This will ensure that the previous selection is updated correctly:

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

Complete Widget Example

Here’s a complete example of our widget using the structure we’ve discussed:

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

Conclusion

In this post, we walked through how to implement a checkbox selection mechanism in a Flutter ListView to ensure that only one checkbox can be selected per question. By using a Map, we effectively managed the selections and updated the UI in response to user input.

Using these concepts, you can easily expand upon this foundation to build more complex survey forms or similar applications. Happy coding!