Solving the Flutter Interactive Viewer Stacking Issue: Tips and Tricks

Learn how to ensure proper stacking of widgets in Flutter's `Interactive Viewer` and how to implement full-screen functionality using visibility widgets.
---

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: Flutter Interactive Viewer child not on top of stack when expanded

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
Solving the Flutter Interactive Viewer Stacking Issue: Tips and Tricks

When working with Flutter's InteractiveViewer, many developers encounter issues related to widget stacking. One common problem arises when an interactive child widget gets overlapped by other components, leading to a less-than-ideal user experience.

In this guide, we’ll tackle a specific case where a flat button appears on top of an expanded image in the InteractiveViewer, and we'll explore a solution that enhances the way interactive containers are displayed.

Understanding the Problem

The challenge presented involves a Flutter setup with a Column containing two Containers, each displaying an image. Below these containers is a flat button for undo functionality. The issue occurs when the first container is expanded via the InteractiveViewer—the undo button appears over the image, causing clutter and obstructing the user interface.

Furthermore, there’s a desire to make images go full-screen upon a long press and exit full-screen mode when the press is released.

Solution Breakdown

Using Visibility Widgets

To resolve the stacking issue and enhance the full-screen functionality, we can leverage the Visibility widget in Flutter. This allows us to control the visibility of various components during interactions effectively.

Here’s a detailed breakdown of the solution:

Step 1: Wrap Widgets in Visibility

Instead of having the flat button and the image containers freely displayed, wrap them in Visibility widgets. This enables flexible control over their display states based on user interactions.

Example of Wrapping Widgets:

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

Step 2: Control Visibility with Functions

You should create functions that trigger visibility changes during the InteractiveViewer animation. When the interaction starts (user taps the image), set the visibility of the other container and the flat button to false. Once the interaction ends, switch them back to true.

Example Functions:

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

Step 3: Implement Full-Screen Effect on Long Press

To enable a full-screen effect upon long pressing the image, we will employ the same Visibility control. By adding listeners to handle long press gestures, you can toggle between regular size and full-screen.

Example Long Press Implementation:

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

Conclusion

By utilizing Visibility widgets wisely and creating control functions for user interactions, we can ensure that our InteractiveViewer displays correctly without overlapping components. This approach not only solves the stacking problem but also enhances the user experience with a seamless transition to full-screen viewing.

Feel free to implement these strategies in your Flutter applications to ensure a more polished and professional interface!