Read the Android system source code online, android Android

Read the Android system source code online, android Android
Http://grepcode.com/project/repository.grepcode.com/java/ext/com.google.android/android/
How can I use android source code to develop android applications? How can I open the source code in chapter 18 (Wireless ordering system) in this book? Can you elaborate?

The development tool is eclipse and can be downloaded for free.
In addition, sdks (used to simulate mobile phones) and ADT (plug-ins for android program development by eclipse) are required)
JDK (java environment) is also required)

After the installation is complete, you can view your book step by step.
The source code in the book can be imported into eclipse to help you compile and run the program.

The specific operation is too cumbersome. Here, it is not that difficult to give you a rough understanding of the concept and read a book.

A website that provides the android operating system source code can be viewed online.

Source.android.com