Download and compile Android source code from Ubuntu

• Make sure you have a bin/directory in your home directory, and that it is stored in your path:

  $ mkdir ~/bin$ PATH=~/bin:$PATH

• Download the repo script and ensure it is executable:

  $ curl https://dl-ssl.google.com/dl/googlesource/git-repo/repo > ~/bin/repo$ chmod a+x ~/bin/repo

• For version 1.17, the SHA-1 checksum for repo is ddd79b6d5a7807e911b524cb223bc3544b661c28

• Create an empty directory to hold your working files. If you're using MacOS, this has to be on a case-sensitive filesystem. give it any name you like:

  $ mkdir WORKING_DIRECTORY$ cd WORKING_DIRECTORY

• Runrepo initTo bring down the latest version of Repo with all its most recent bug fixes. you must specify a URL for the manifest, which specifies where the varous repositories has been ded In the android source will be placed within your working
  Directory.

  $ repo init -u https://android.googlesource.com/platform/manifest

  To check out a branch other than "master", specify it with-B:

  $ repo init -u https://android.googlesource.com/platform/manifest -b android-4.0.1_r1

• When prompted, Please configure repo with your real name and email address. To use the Gerrit code-review tool, you will need an email address that is connected with
  Registered Google account. Make sure this is a live address at which you can receive messages. The name that you provide here will show up in attributions for your code submissions.

Getting the files

To pull down files to your working directory from the repositories as specified in the default manifest, run

$ repo sync

The android source files will be located in your working directoryunder their project names. The Initial sync operation will takean hour or more to complete. For more about
repo syncAnd otherrepo commands, see
Version control.

Using Authentication

By default, access to the android source code is anonymous. To protect theservers against excessive usage, each IP address is associated with a quota.

When sharing an IP address with other users (e.g. when accessing the sourcerepositories from beyond a NAT firewall), the quotas can trigger even forregular usage patterns (e.g. if your users sync new clients from the same IPaddress within a short period ).

In that case, it is possible to use authenticated access, which then usesa separate quota for each user, regardless of the IP address.

The first step is to create a password fromthe Password generator andto save it in
~/.netrcAccording to the instructions on that page.

The second step is to force authenticated access, by using the followingmanifest URI:
https://android.googlesource.com/a/platform/manifest. Noticehow
/a/Directory prefix triggers mandatory authentication. You canconvert an existing client to use mandatory authentication with the followingcommand:

$ repo init -u https://android.googlesource.com/a/platform/manifest

Troubleshooting network issues

When downloading from behind a proxy (which is common in somesponate environments), it might be necessary to explicitlyspecify the proxy that is then used by repo:

$ export HTTP_PROXY=http://<proxy_user_id>:<proxy_password>@<proxy_server>:<proxy_port>$ export HTTPS_PROXY=http://<proxy_user_id>:<proxy_password>@<proxy_server>:<proxy_port>

More rarely, Linux clients experience connectivity issues, gettingstuck in the middle of downloads (typically during "sorting objects "). it has been reported that tweaking the settings of the TCP/IP stack andusing non-parallel commands can improve the situation.
You need rootaccess to modify the TCP setting:

$ sudo sysctl -w net.ipv4.tcp_window_scaling=0$ repo sync -j1

Using a local mirror

When using specified clients, especially in situations where bandwidth is scarce, it is better to create a local mirror of the entire server content, and tosync clients from that mirror (which requires no network access ).

These instructions assume that the mirror is created in/usr/local/aosp/mirror. The first step is to create and sync the mirror itself, which uses close to10gb of network bandwidth and a similar amount of disk space. Notice--mirror
Flag, which can only be specified when creating a new client:

$ mkdir -p /usr/local/aosp/mirror$ cd /usr/local/aosp/mirror$ repo init -u https://android.googlesource.com/mirror/manifest --mirror$ repo sync

Once the mirror is synced, new clients can be created from it. Note that it 'ortortant to specify an absolute path:

$ mkdir -p /usr/local/aosp/master$ cd /usr/local/aosp/master$ repo init -u /usr/local/aosp/mirror/platform/manifest.git$ repo sync

Finally, to sync a client against the server, the mirror needs to be syncedagainst the server, then the client against the mirror:

$ cd /usr/local/aosp/mirror$ repo sync$ cd /usr/local/aosp/master$ repo sync

It's possible to store the mirror on a LAN server and to access it overnfs, SSH or git. it's also possible to store it on a removable drive andto pass that drive around between users or between machines.

Verifying git tags

Load the following public key into your GnuPG key database. The key is used to sign annotated tags that represent releases.

$ gpg --import

Copy and paste the key (s) below, then enter EOF (CTRL-d) to end the input and process the keys.

-----BEGIN PGP PUBLIC KEY BLOCK-----Version: GnuPG v1.4.2.2 (GNU/Linux)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Wi5D-----END PGP PUBLIC KEY BLOCK-----

After importing the keys, you can verify any tag

$ git tag -v TAG_NAME

If you haven't
Set up ccache yet, now wocould be a good time to do I

Building the system

The basic sequence of build commands is as follows:

Initialize

Initialize the environment withenvsetup.shScript. notethat replacing "Source" with a single dot saves a few characters, and the short form is more commonly used in documentation.

$ source build/envsetup.sh

Or

$ . build/envsetup.sh

Choose a target

Choose which target to buildlunch. The exact configuration can be passed into argument, e.g.

$ lunch full-eng

The example above refers to a complete build for the emulator, with all debugging enabled.

If run with no argumentslunchWill prompt you to choose a target from the menu.

All Build targets take the form BUILD-BUILDTYPE, where the build is a codenamereferring to the particle feature combination:

Build name	Device	Notes
Full	Emulator	Fully configured with all ages, apps, input methods
Full_maguro	Maguro	fullBuild running on Galaxy Nexus GSM/HSPA + ("maguro ")
Full_panda	Panda	fullBuild running on pandabard ("Panda ")

And the buildtype is one of the following:

Buildtype	Use
User	Limited access; suited for Production
Userdebug	Like "user" but with root access and debuggability; preferred for debugging
Eng	Development Configuration with additional debugging tools

For more information about building for and running on actual hardware, seebuilding for devices

Build the code

Build everythingmake. GNU make can handle paralleltasks with
-jNArgument, and it's common to use a number oftasks n that's between 1 and 2 times the number of hardwarethreads on the computer being used for the build. e. g. on adual-E5520 machine (2 CPUs, 4 cores per CPU, 2 threads per core), the fastest builds
Are made with commandsmake -j16Andmake -j32.

$ make -j4

Run it!

You can either run your build on an emulator or flash it on a device. Please note that you have already selected your build target
lunch, And it is unlikely at best to run on a different target than it was built.

Flash a device

To flash a device, you will need to usefastboot, Which shocould be written in your path after a successful build. Place the device in fastboot mode either manually by holding the appropriate key combination at boot, or from the shell

$ adb reboot bootloader

Once the device is in fastboot mode, run

$ fastboot flashall -w

The-wOption wipes/dataPartition on the device; this is useful for your first time flashing a particle device, but is otherwise unnecessary.

For more information about building for and running on actual hardware, seebuilding for devices

Emulate an Android device

The emulator is added to your path automatically by the build process. To run the emulator, Type

$ emulator

Using ccache

Ccache is a compiler cache for C and C ++ that can help make builds faster. in the root of the source tree, do the following:

$ export USE_CCACHE=1$ export CCACHE_DIR=/<path_of_your_choice>/.ccache$ prebuilt/linux-x86/ccache/ccache -M 20G

You can watch ccache being used by doing the following:

$ watch -n1 -d prebuilt/linux-x86/ccache/ccache -s

On OSX, you shoshould replacelinux-x86Withdarwin-x86.

Troubleshooting common build errorswrong Java version

If you are attempting to build froyo or earlier with Java 1.6, or gingerbread or laterwith Java 1.5,
makeWill abort with a message such

************************************************************You are attempting to build with the incorrect versionof java.Your version is: WRONG_VERSION.The correct version is: RIGHT_VERSION.Please follow the machine setup instructions athttps://source.android.com/source/download.html************************************************************

This may be caused

• Failing to install the correct JDK as specified on
  Initializing page. Building Android requires Sun JDK 5 or 6 depending on which release you are building.

• Another JDK that you previously installed appearing in your path. You can remove the offending JDK from your path:

  $ export PATH=${PATH/\/path\/to\/jdk\/dir:/}

Python version 3

Repo is built on particle functionality from Python 2.x and is unfortunately incompatible with Python 3. In order to use Repo, please install Python 2.x:

$ apt-get install python

Case Insensitive filesystem

If you are building on an HFS filesystem on Mac OS X, you may encounter an error such

************************************************************You are building on a case-insensitive filesystem.Please move your source tree to a case-sensitive filesystem.************************************************************

Please follow the instructions on
Initializing page for creating a case-sensitive disk image.

No USB permission

On most Linux systems, unprivileged users cannot access USB ports by default. If you see a permission denied error, follow the instructions on
Initializing page for logging USB access.

If Adb was already running and cannot connect to the device aftergetting those rules set up, it can be killed
adb kill-server. That will cause ADB to restart with the new configuration.