React Native Drag-and-Drop Flicker Bug Exploration

TL;DR

• Encountered a flicker bug after upgrading React Native in a drag-and-drop feature.
• Hypothesized it’s related to state handling or improper responder coordination.
• Adjusted activation distances as a workaround, but it didn’t resolve the issue.
• Systematically ruled out components and effects to isolate the problem.
• Next steps involve deeper exploration of the nestable scroll container component.

Blog Post

Working on a frustrating flicker bug in a React Native drag-and-drop feature after a recent upgrade. The flicker occurs when items are dragged and released, causing them to briefly display in their original position before settling at the intended destination.

I initially suspected state management issues or conflicts between responder controls of nested components.

1. Activation Distance Hack: I tried setting the activation distance to trigger dragging more smoothly, but it didn’t resolve the flicker.

2. Component Isolation: By manipulating parent and child component interactions and logging state updates, I attempted to rule out extraneous renders or state mismanagement.

3. Styling Removal and Effects Commenting: Systematically stripped down components to bare functionality, suspecting any unnecessary renders might contribute to the problem—but the flicker persisted.

4. Nestable Container Reexamination: Plan to investigate deeper into the nestable scroll containers managing touch events. It’s becoming evident that the bug lies somewhere in this complex interaction.

The resolution isn’t clear yet, pushing forward demands more creative troubleshooting and possibly exploring logs for insights into React Native’s changes post-upgrade.

This exploration of potential leads and unsuccessful strategies is crucial in tracing down the flicker phenomenon. Round two awaits!