Solving the TextFormField is not working Issue in Flutter

Discover how to easily fix the `TextFormField` issue in Flutter by leveraging constraints to create a properly functioning layout.
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Solving the TextFormField is not working Issue in Flutter

If you're encountering a frustrating problem where your TextFormField isn't functioning as expected in Flutter, you're not alone. Many developers face issues related to layout and constraints, particularly when using widgets like Stack and Positioned. In this guide, we'll delve into a common issue that arises in this context and guide you through the steps needed to resolve it effectively.

The Problem

In your Flutter application, you may have written code similar to the following:

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

When you run this code, you might encounter an error message indicating that the TextFormField cannot be displayed correctly due to a lack of constraints, hence the phrase "needs compositing." This is primarily due to the way Flutter handles layouts with Stack and Positioned widgets.

Error Explanation:

The Stack widget sizes itself based on its non-positioned children.

In this case, you have no non-positioned children, leading the Stack to layout positioned children in unbounded space.

Consequently, the TextFormField tries to expand in this unbounded space, resulting in application failures.

The Solution

Revised Code:

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

Key Changes:

Specifying Constraints: By doing this, you enable proper layout where the Column can manage the size of its children effectively.

Understanding the Quirk of Stack

The layout issue with your initial code arises from a basic understanding of how the Stack widget operates:

Stack evaluates its size based on non-positioned children.

In your implementation, having zero non-positioned children means that the Stack lays out positioned children in what's termed as "unbounded space."

This leads to:

Column trying to layout widgets without boundaries.

The TextFormField attempting to expand infinitely, which causes layout exceptions in Flutter.

Allow Column to manage its children's size.

Ensure TextFormField has clear boundaries within the layout, thus eliminating the error.

Conclusion

For anyone working with Flutter layouts, understanding how different widgets interact with constraints is crucial for developing smooth, functional applications. Don't hesitate to explore and experiment with your layout structures to master Flutter's complex yet powerful UI framework.