How to build Flutter project with Android aar file?

After learning the Flutter example - hello services, I have successfully built my Flutter project with aar file.

Basic Steps:

1. Download the Flutter source code.
2. Open flutter/examples/hello_services/android in Android Studio.
3. Click File > New > New Module and choose Import .JAR/.AAR Package.
4. Press F4 to open Project Structure, and then add the dependent module.
5. Write Java code to invoke APIs that defined in aar file.
6. Import flutter/examples/hello_services to Intellij IDEA.
7. Build and run the Flutter app.

I've pushed the source code to GitHub.