You can step in, out, and over Dart statements, hot reload or resume the app,
and use the debugger in the same way you’d use any debugger.
The 5: Debug button toggles display of the debug pane.

Flutter inspector

There are two other features provided by the
Flutter plugin that you might find useful.
The Flutter inspector is a tool for
visualizing and exploring
the Flutter widget tree and helps you:

Understand existing layouts

Diagnose layout issues

Toggle display of the inspector using the
vertical button to the
right of the Android Studio window.

Flutter outline

The Flutter Outline displays the build method in visual form.
Note that this might be different than the widget tree for the
build method. Toggle display of the outline using the vertical
button to the right of the AS window.