How Hot Reload works internally

Question

Hi Guys,

I am new in Flutter Framework. I am able to perform Hot Reload in my app. But can anyone tell me how it works behind the scene?

Answer 1

Hi@akhtar,

When Hot Reload is invoked, the host machine looks at the edited code since the last compilation. The following libraries are recompiled.

• Any libraries with changed code

• The application’s main library

• The libraries from the main library leading to affected libraries

The source code from those libraries is compiled into kernel files and sent to the mobile device’s Dart VM. The Dart VM re-loads all libraries from the new kernel file. So far no code is re-executed. The hot reload mechanism then causes the Flutter framework to trigger a rebuild/re-layout/repaint of all existing widgets and render objects.