The AOSP build system includes the abstraction layers to build a device. After we understand the ideas behind these layers, it will help us to understand the relationship of the various Makefiles for a device. It is always good to refer to the original Google document at the following URL, when you start to create a new device. The information will usually be updated when a new Android release is available: http://source.android.com/source/add-device.html.
In this section, we will apply the information from the previous Google document to the specific Android emulator virtual hardware that we are going to work on. In this way, we can derive all device-specific Makefiles according to the general guidance from the previous Google document. Throughout the process from generic to specific, we can apply the inheritance of object-oriented concepts to the Makefile system.
There are three layers...