In order to access the classes from the Android plugin, you need to add plugins/android/lib/android.jar to the classpath of your IntelliJ IDEA SDK.

• https://proandroiddev.com/write-an-android-studio-plugin-part-1-creating-a-basic-plugin-af956c4f8b50
• https://intellij-support.jetbrains.com/hc/en-us/community/posts/206107809-Android-Studio-Plugin-SDK
• https://github.com/Haehnchen/idea-android-studio-plugin