Tip:
  The code for your app is in lib/main.dart.
  For a high-level description of what each code block does,
  see the comments at the top of that file.

Run the app

Check that an Android device is running.
If none are shown, follow the device-specific instructions
on the Install page for your OS.

        $ flutter devices

Run the app with the following command:

        $ flutter run

After the app build completes, you’ll see the starter app on your device.

Try hot reload

Flutter offers a fast development cycle with Stateful Hot Reload,
the ability to reload the code of a live running app without
restarting or losing app state.
Make a change to app source,
tell your IDE or command-line tool that you want to hot reload,
and see the change in your simulator, emulator, or device.

Open lib/main.dart.