[FIXED] Flutter : How to Debug which widgets re-rendered on state change

Issue

I am using Redux with Flutter for state management. Whenever I dispatch an action, I want to know which widgets were re-rendered. Is there any way of doing it?

Solution

In flutter, whenever one widget update ; the whole widget tree repaint. So... no.

But you can also introduce "repaint boundaries" manually by inserting in your tree a RepaintBoundary widget. This explicitly tells flutter to create a new painting layer for it's child (which implies memory cache). So that whenever that child updates, it won't repaint it's parent too.

What you can do is instead debug when a RepaintBoundary is repainted.

For this you can enable repaint rainbow by:

• Pressing t when using flutter run
• Using vscode Dart Code extension with a ctrl/cmd + shift + p and enable repaint rainbow

Answered By - Rémi Rousselet
Answer Checked By - Timothy Miller (JavaFixing Admin)