This is the second day of my participation in the More text Challenge. For more details, see more text Challenge
The preparatory work
Configure the Android Studio
** Adjust memory size: ** Android Studio requires a large amount of memory to load The Android source code, so it is common to run out of memory and need more memory. Go to Help-> Edit Custom VM Options, such as “-xms4096m -XMx4096m”
More information:
- The Android Studio’s official website
- Configure the Android Studio
Configure repo
Download the repo tool
mkdir ~/bin
PATH=~/bin:$PATH
curl https://storage.googleapis.com/git-repo-downloads/repo > ~/bin/repo
chmod a+x ~/bin/repo
Copy the codeOr use tunaGit – ‘image
And then create a working directory (whatever name you want)
Mkdir ~/aosp // Create a directory. You can define CD ~/aospCopy the codeInitialize the warehouse:
repo init -u https://aosp.tuna.tsinghua.edu.cn/platform/manifest
Copy the codeIf you are prompted that you cannot connect to Gerrit.googlesource.com, refer to the update section of the Git-repo help page.
If you need a specific Android version (List of Android versions) :
Repo init -u https://aosp.tuna.tsinghua.edu.cn/platform/manifest - b android - 9.0.0 _r1Copy the codeSynchronize the source tree (just execute this command in the future) :
#Synchronize all available projects
repo sync
#Only the currently initialized branch is synchronized
repo sync -c -j4
#Only the Frameworks/Base library is synchronized
repo sync platform/frameworks/base -c -j4
Copy the codeRepo sync failure
So we need to create an automatic download script that will automatically execute repo sync if an error occurs, create a down.sh script in the aosp folder, (create a down.sh file in the aosp folder and open it with an editor, -j 8 can be changed by yourself, your total number of CPU threads *2:
#! /bin/bash
repo sync -j 8
while[$? = 1];do
echo"======sync failed, re-sync again======" Sleep 3 repo sync-j8done
Copy the codeIf you only need to synchronize part of the project
Replace the top two lines repo sync -j 8 with the following statement
repo sync platform/development platform/frameworks/base -j8
Copy the codeAfter the repo sync command, you can specify the project to be synchronized. The above command specifies two projects to open. Repo /manifest.xml, you can see the name and path of the project.
Then the command line is executed, and the download starts. (Note: Terminal is in the AOSP folder)
chmod a+x down.sh
./down.sh
Copy the codeReplace the existing AOSP source code with remote
If you already have the AOSP source code in some way (or if you just init it) and you want to synchronize the AOSP part of the code through TUNA, Just need to repo/manifest. This remote XML to the aosp fetch from https://android.googlesource.com instead https://aosp.tuna.tsinghua.edu.cn/.
<manifest>
<remote name="aosp"
- fetch="https://android.googlesource.com"
+ fetch="https://aosp.tuna.tsinghua.edu.cn"
review="android-review.googlesource.com" />
<remote name="github"
Copy the codeAt the same time, to modify. Repo/manifests. Git/config, will be
url = https://android.googlesource.com/platform/manifest
Copy the codeChange to
url = https://aosp.tuna.tsinghua.edu.cn/platform/manifest
Copy the codeconclusion
We don’t need all the code to analyze the source code, because AOSP includes not only the system source code, but also some tool code, such as AAPT, ADB, etc., which we don’t need, and even the system source code, we don’t need to read all of it, if you do read all of it, you will never read all of it.
If you only want to download a single directory, such as we want to download the platform/frameworks/base/directory of the code, we can git clone android.googlesource.com/platform/fr… But again, there’s the problem of going over the wall, and of course we can use mirrors.
Mirror address aosp.tuna.tsinghua.edu.cn/, for instance we should download platform/frameworks/base/directory, use the git clone aosp.tuna.tsinghua.edu.cn/platform/fr… If you have enough bandwidth, you can usually download the single source code you want in a few minutes.
If you want to download a single file, or search for file names and codes, you can go to AndroidXref.com/, which has some of the Android source code
For details, see How to Read Android Framework Source Code in Android Studio
Todo www.jianshu.com/p/367f0886e… Compile the source code
Wiki.archlinux.org/index.php/A…
There are arch system to install aosputil external hard disk to ext4 format
Python2 environment switch
source.android.com/setup
Source.android.com/source/buil…
Blog.csdn.net/dd864140130…
Introduction to Android Architecture
The overall architecture
The Android system architecture is divided into five layers, which are application layer, application framework layer, system runtime layer, hardware abstraction layer and Linux kernel layer from top to bottom.
| The Android source root directory | describe |
|---|---|
| abi | Abi: Application binary interface |
| art | A new runtime environment that needs to be differentiated from the Dalvik VM |
| bionic | System C library |
| bootable | Boot boot related code |
| build | Store system compilation rules and generic and other basic development and configuration packages |
| cts | Android Compatibility Test Suite standard |
| dalvik | Dalvik virtual machine |
| developers | Developer directory |
| development | Application development |
| device | Device Configuration |
| docs | Reference Documents |
| external | Some open source modules used by Android |
| frameworks | Application framework, the core part of the Android system, written in Java and C++ |
| hardware | The main hardware adaptation layer HAL code |
| libcore | Core library related files |
| libnativehelper | Support Functions for Android’s Class libraries is an acronym for Support Functions for Android’s class libraries |
| ndk | The Android NDK (Android Native Development Kit) is a series of Development tools that allow developers to embed unmanaged code written in C/C++ in Android applications |
| out | The compiled code is printed in this directory |
| packages | Application package |
| pdk | Short for Plug Development Kit, local Development Kit |
| platform_testing | The platform test |
| prebuilts | Precompiled resources for x86 and ARM architectures |
| sdk | SDKS and emulators |
| system | File systems and applications and components are implemented in C language |
| toolchain | Toolchain file |
| tools | Tool file |
| Makefile | Global Makefile that defines compilation rules (usually with a.mk file suffix) |
Application layer
The application layer is located at the top of the entire Android system. The applications developed by developers and the applications built in the system are in the application layer. The packages directory in the source root corresponds to the system application layer.
| Packages directory | describe |
|---|---|
| apps | Core application |
| experimental | Third party applications |
| inputmethods | Input method directory |
| providers | Content provider directory |
| screensavers | The screen saver |
| services | Communication service |
| wallpapers | The wallpaper |
Application framework layer part
Application framework layer is the core part of the system. On the one hand, it provides interfaces to the application layer, and on the other hand, it connects with C/C++ library and hardware abstraction layer. The main implementation code for the application framework layer is in the /frameworks/base and /frameworks/av directories
In the frameworks/base/services part of the system service, in the frameworks/av/services stored audio and camera services.
The directory structure of /frameworks/base is as follows
| / frameworks/base directory | describe | / frameworks/base directory | describe |
|---|---|---|---|
| api | Define the API | cmds | Important commands: am and app_proce |
| core | Core library | data | Data files such as fonts and sounds |
| docs | The document | graphics | Graph image correlation |
| include | The header file | keystore | Related to data signing certificates |
| libs | library | location | Location-related libraries |
| media | Multimedia correlation library | native | The local library |
| nfc-extras | NFC related | obex | Bluetooth transmission |
| opengl | 2 d / 3 d graphics API | packages | Setup, TTS, VPN program |
| sax | The XML parser | services | System services |
| telephony | Telephone communication management | test-runner | Test Tool Related |
| tests | Relevant test | tools | tool |
| wifi | Wifi network |
C/C++ library section
C/C++ libraries in system runtime layer (Native) are of various types and powerful functions. C/C++ libraries are not completely in one directory. Here give several common and more important C/C++ library directory location.
| Directory location | describe |
|---|---|
| bionic/ | The System C library developed by Google is open source under a BSD license. |
| /frameworks/av/media | System media library |
| /frameworks/native/opengl | 3D graphics library/third party graphics rendering library |
| /frameworks/native/services/surfaceflinger | Graphics display library, mainly responsible for graphics rendering, overlay and rendering functions |
| external/sqlite | A C++ implementation of lightweight relational database SQLite |
| external/webp,external/webrtc | Network engine library |
The system runtime part
Implementation of Dalvik VIRTUAL machine: / Dalvik. Starting from Android 5.0, the default running environment of Android applications is ART (Android Runtime), and ART mode has faster and higher running efficiency. ART: /art
Hardware abstraction layer part
Hardware/libHardware: AUDIO, NFC, power implementation RIL: wireless hardware devices and telephone implementation
Read the tool
vim+ctags+cscope
Linux platform to read the source tool
Source Insight/Understand
(1) Source Insight
How to read Android source code
OpenGrok
Build a large source reading environment – using OpenGrok
Tool to use -Mac build OpenGrok view Android source code
androidxref
Android Code Search
Online, openGrok has not recommended, the current official has an online version, very good use.
Android Code Search
Android Studio
Import the AOSP source code into Android Studio
reference
Get Android source code, first source module architecture
Github asop mirror
Android system architecture and system source directory
Download AOSP Android source code (minimum and fastest download method, skip compilation and directly import android Studio) Ubuntu 16.04
Building the AndroidStudio source development environment