Discussion: Android top-level source code structure

As an underlying developer, especially the underlying Android development, the most basic thing is to be familiar with the android source code. The android source code directory is very large, including the android compilation script, target code, host compilation tool, and simulation environment.

Top-level directory:

| -- Makefile

Global makefile.

| -- Bionic

Bionic libc library

| -- Bootable

Boot Loader, recovery system, which contains U-boot, that is, bootloader, which is used to guide the operating system to run. Programs run first after the machine is powered on.

| -- Build

Compile and configure the required scripts and tools.

| -- Dalvik

For Java virtual machines, many people do not understand why Java virtual machines are required because the operating system is written in C language and the android program is written in Java. Therefore, the runtime environment must be provided for Java, and provides most of the functions of the core library of Java programming language. Oh, are you sure you have any questions? Isn't Android an operating system? If you think so, it's wrong! Android is a mobile device software heap that includes the operating system, favorite parts, and key applications. Android is based on the Linux operating system.

| -- Development

Templates and tools required for program development.

| -- External

External library.

| -- Frameworks

Android Application Framework.

| -- Hardware

Hardware-related libraries.

| -- Kernel_xxx

Linux2.6 kernel source code, xxx indicates the corresponding development board model.

| -- Packages

Application.

| -- Prebuilt

Pre-compiled host and target machine programs and tools.

| -- SDK

SDK.

| -- System

Android root directory.

| -- Device

Various vendors configure, compile scripts, and disable source binary.

Due to the time relationship, we will introduce the top-level source code for the moment.