FlutterWindow

::

OnCreate

()

// ...

RegisterPlugins

flutter_controller_

>

engine

());

flutter

::

MethodChannel

<>

channel

flutter_controller_

>

engine

()

>

messenger

(),

"samples.flutter.dev/battery"

flutter

::

StandardMethodCodec

::

GetInstance

());

channel

SetMethodCallHandler

[](

const

flutter

::

MethodCall