Скачать или смотреть Fixing GestureDetector Tap Issues with Transform in Flutter Navbar

Learn how to properly position a raised center button in a Flutter navbar so that GestureDetector's onTap event works correctly when using Transform for animation or layout adjustments.
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This video is based on the question https://stackoverflow.com/q/79514558/ asked by the user 'SilkeNL' ( https://stackoverflow.com/u/10878426/ ) and on the answer https://stackoverflow.com/a/79514980/ provided by the user 'SilkeNL' ( https://stackoverflow.com/u/10878426/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Problem Overview

When creating a Flutter navbar with a raised circular center button, using a Transform.translate to position this circle higher breaks the GestureDetector's onTap handler for the part positioned outside its original bounds. This happens because Transform affects only visual layout, not the widget's hit testing area.

Why Does This Happen?

Transform modifies only the visual position of a widget but does not affect the gesture detection area.

The tappable area remains in the widget's original place, causing taps on the visually moved part to be ignored.

Recommended Solution: Use Positioned Instead of Transform

Instead of translating the center button inside the row, lift it out of the row and position it absolutely using a Stack with Positioned. This ensure:

The widget's hit test area matches its visible position.

Tap interactions work as expected.

Implementation Guide

Initial Navbar Structure

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

The center item is no longer in the Row's mapIndexed loop.

A SizedBox placeholder reserves its space to avoid layout shifts.

Defining the TapbarCenterItem

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

Positioned places the widget absolutely inside the Stack.

behavior: HitTestBehavior.opaque expands the hit area to the entire widget bounds.

Key Takeaways

Avoid using Transform.translate for changing interactive elements’ position if you want to preserve tap behavior.

Use Stack with Positioned to place widgets “above” others physically and logically.

Reserve layout space in the original widget structure to prevent overflow or alignment issues.

Applying these patterns will ensure your raised navbar button receives taps correctly and your UI behaves as expected.