Resolving Dynamic Button Visibility in Flutter Based on TextField Input

Learn how to dynamically show a button in Flutter when a user inputs data into a TextFormField. Easy steps to enhance your UI!
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Understanding Dynamic Button Visibility in Flutter

Have you ever faced the issue where a button does not appear to users immediately after they type data into a TextFormField in Flutter? This common problem can be frustrating, especially when you want your app's user interface to respond promptly to user inputs. In this guide, we’ll explore a solution that allows you to dynamically display a button based on the data entered in the TextFormField.

The Problem

In the scenario presented, the developer wants to show a button when a user enters a value into a TextFormField. However, the button only appears after a manual hot reload, indicating a problem with the UI not updating as expected right after data input. Here’s a snippet illustrating the issue:

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

In the code above, the button is conditionally displayed based on the content of the _weight controller. However, due to Flutter's widget lifecycle, the UI does not automatically rebuild when input changes, which is why the button doesn’t appear until a hot reload.

The Solution

To resolve this issue, we need to ensure that our UI responds to changes in the TextFormField immediately. This can be accomplished by adding a listener to the TextEditingController to call setState. Here’s how:

Step 1: Add a Listener to Your Controller

First, initialize your TextEditingController with a listener that triggers setState whenever the text changes, allowing the UI to rebuild:

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

Step 2: Update the UI with setState

Using setState, the widget will rebuild every time the listener is triggered. This ensures that whenever the text in the TextFormField changes, your button's visibility checks will run, and the UI updates accordingly.

Step 3: Clean Up Resources

It's a good practice to dispose of the controller when it's no longer needed. Override the dispose method in your widget to prevent memory leaks:

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

Complete Updated Example

Here’s how the complete implementation would look:

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

Conclusion

By implementing a listener on the TextEditingController and utilizing setState, you can efficiently manage the visibility of buttons or any other widgets in your Flutter application based on user input. This approach ensures a smooth and dynamic user experience.

We hope this blog helped you understand how to show a button based on TextFormField data in Flutter! If you have any questions or need further assistance, feel free to leave a comment below.