Скачать или смотреть How to Validate a TextField in a Bottom Sheet in Flutter Without Closing It

Discover an effective method for validating a non-`TextFormField` in a Flutter bottom sheet, ensuring error messages can be displayed without closing the sheet.
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This video is based on the question https://stackoverflow.com/q/68557006/ asked by the user 'shanmkha' ( https://stackoverflow.com/u/16094734/ ) and on the answer https://stackoverflow.com/a/68559511/ provided by the user 'Mohammad Hosein' ( https://stackoverflow.com/u/10352839/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Validating a TextField in a Bottom Sheet Without Closing It

Flutter developers often encounter situations where they need to validate user input in a UI component. One common scenario is ensuring that a TextField inside a bottom sheet contains valid data before allowing further actions, such as saving the input. This guide will guide you through the process of validating a TextField in a bottom sheet, specifically preventing the sheet from closing while still providing feedback to the user.

Problem Statement

In Flutter, when you click a button to save data entered in a TextField located inside a modal bottom sheet, the common issue is that the bottom sheet closes inadvertently when the validation logic triggers. The objective is to implement a way to validate the text field input and display an error message without closing the bottom sheet.

Proposed Solution

To address this issue, we can utilize a ChangeNotifier class along with the Provider package. This allows us to efficiently manage and notify changes within our Flutter app, ensuring that validations can be checked and errors displayed without requiring the bottom sheet to be dismissed.

Step-by-Step Implementation

Below is a breakdown of the code required to implement the solution, ensuring that the validation works appropriately.

Set Up Provider Dependencies

First, ensure that you include the provider package in your pubspec.yaml file:

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Creating the Main App and Bottom Sheet

Start by creating a basic Flutter application and the corresponding UI layout with a bottom sheet using showModalBottomSheet:

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Creating the Custom Text Field Widget

Create a custom widget that includes the TextField, validation logic, and an error display:

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Implementing ChangeNotifier for Validation Logic

Finally, create a class that extends ChangeNotifier to manage the state and validation logic:

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Final Thoughts

Using the approach outlined above, you can effectively validate the content of a TextField within a bottom sheet while keeping it open. This technique enhances user experience, ensuring that users are promptly informed of input errors without interrupting their workflow.

By integrating a state management solution like Provider, the overall architecture of your Flutter app is improved, making it more responsive and maintainable.

Now go ahead and implement this solution in your next Flutter project, and see how smooth user interaction can be!