developing android tips and tricks

Developing Androidtips and tricks

Amarula Solutions BV

Alberto [email protected]

Alberto Panizzo 2/53www.amarulasolutions.com

Who am IAlberto [email protected] Degree:

Ing. Informatica @ Padova2010 Joined Penguin Group:

Group of professionals in Linux/Embedded that aimed to conquer the world

2011- CTO Co-Founder at Amarula SolutionsSeveral porting of Linux/Android on industrial mobile devices from boot to apps

10+ Years experience of Linux, 5 Years with Android/ARM


Overview Squeezed intro about Android Managing the sources Drive the Build System Interaction with the target Debug and Trace Misc things Other thoughts Q/A


Devices ecosystem


Devices ecosystem

DARTPXA320

RP1100S5PV210


Architecture


Managing the sources Git Repo


Git Android use git to manage ALL

sub-projects Better you know git, easier will be your life A lot of documentation of git:

man$ man git $ man git

Cheat Sheetshttps://git.wiki.kernel.org/index.php/GitCheatSheet

Book Pro Githttp://git-scm.com/book


GitUseful but uncommon git cmds:

git clone --reference # To save bandwith and # time

git add -p # To add single changesgit add -p file-name # from a file

git stash # To modify a patch git rebase --interactive ^ # already queued

git reflog # To do not miss anything


Repo Python wrapper to git that manage

projects made of multiple git sub-projects Uses an XML manifest to describe the prj The manifest itself is kept with git Start from a good manifest!

OSS is code reusing as well so start from a good codebase to easy your life


RepoInstall:$ curl https://dl-ssl.google.com/dl/googlesource/git-repo/repo >

~/bin/repo && PATH=~/bin:$PATH

Setup a local repository:$ mkdir local-prj && cd local-prj$ repo init -u [-b branch-to-use] [-m mname]

Checkout and update against remote:$ repo sync


RepoInteresting things:

Look at what is happening in sub-projects .git dir:$ ls -l build/.gittotal 64-rw-rw-r-- 1 alberto alberto 80 Jul 2 19:22 COMMIT_EDITMSGlrwxrwxrwx 1 alberto alberto 37 Dec 3 2012 config ->

../../.repo/projects/build.git/configlrwxrwxrwx 1 alberto alberto 42 Dec 3 2012 description ->

../../.repo/projects/build.git/description-rw-rw-r-- 1 alberto alberto 34 Apr 10 18:54 HEADlrwxrwxrwx 1 alberto alberto 36 Dec 3 2012 hooks ->

../../.repo/projects/build.git/hooks-rw-rw-r-- 1 alberto alberto 57072 Jul 2 19:22 indexlrwxrwxrwx 1 alberto alberto 35 Dec 3 2012 info ->

../../.repo/projects/build.git/info

the real git index is inside .repo !!+ To checkout fast a new Android version, re-use

the previous .repo dir- Do not do use git clone with projects you want to add


Repo manifestsSetup a git project with default.xml like:

...


Repo manifestsAdd locally projects to the tree

Add manifests in: .repo/local_manifests/name.xml

...


Drive the Build System Setup the environment Interesting functions Interesting targets Add projects to the build Add custom global dependencies A Revelation


Setup the environmentBefore start working do source: . build/envsetup.sh

Interesting tools gained: lunch [combo-string] [combo-idx] mm # Build all modules below the

# current path mmm path:module # Build only module within path

... hmm # Enumerate all tools


Interesting targetsThese are make targets:

make sdk # Build an sdk with the current api

make showcommands # Show full cmd line for build # steps

make otapackage # Build installation packages but # pray your HW is not so different

make droid # Default build target


Adding a project to the buildThis for a java App:

Move your freaky app to packages/apps/MyApp Create packages/apps/MyApp/Android.mk as:

Build it with: mmm packages/apps/MyApp

LOCAL_PATH:= $(call my-dir)include $(CLEAR_VARS)

LOCAL_MODULE_TAGS := optionalLOCAL_SRC_FILES := $(call all-java-files-under, src)LOCAL_PACKAGE_NAME := MyApp LOCAL_CERTIFICATE := platform

include $(BUILD_PACKAGE)


Add custom global dependenciesIn build/core/main.mk:

Add dependencies to droid OR Add a target that depends on droid OR Define a target before droid and depend on this


A RevelationAdd custom dependencies to a LOCAL_MODULE:

LOCAL_ADDITIONAL_DEPENDENCIES := mydep

include $(BUILD_EXECUTABLE)

.PHONY: mydep

mydep:echo Is that strong your faith to think this is a Revelation??

I accept cash or money transfers for this revelation :D $$


Interaction with the target Bootloader level: Fastboot Holy Grail: adb Android shell


Fastboot Nice tool/protocol to speak to the bootloader Uses USB interface ++Speed!! Several reference integrations to u-boot

Samsung s5pv210: https://code.google.com/p/x210ii/

TI OMAP: http://www.omappedia.com/wiki/Android_Fastboot

None on uboot mainline Used to do raw flashing / boot images /

execute custom boot.img


Adb Main OS-layer debug tool Common adb commands:

Obtain a shell:$ adb shell

Obtain a root shell in userdebug builds:$ adb root ; adb shell

Push pull files to the device:$ adb [push|pull]

Install/Uninstall packages:$ adb [install|uninstall]


Adb Useful adb commands:

Use TCPIP transport:$ adb tcpip 5555It does set the properties:

persist.adb.tcp.port and service.adb.tcp.port to 5555and restart device's adb server

On the workstation do:$ export ADBHOST=192.168.X.XXX$ adb kill-server ; adb devices


A note on the shell Until 2.3 Android had the light bare ash

system/core/sh Not even test was built in!!

[ $? != 0 ] && echo ERROR # Ehm.. IMPOSSIBLE Auto-completion ? Where are you coming from? Mars??

Since v3 Android has the powerful mksh external/mksh/ Even Arithmetics!!

root@android:/ # echo $(( 1 + 1 )) 2

The paradise is here!


Debug and Trace Logging

Kernel (dmesg) Logcat

Debug traces Refresh libs


Kernel log You can do dmesg only if you are root

No dmesg on production builds:# su 2000 dmesgklogctl: Operation not permitted

While developing the kernel cmdline have. debug no_console_suspend

Turn on CONFIG_PRINTK_TIME for timestamps Can output to /dev/kmsg to synchronize

userspace logging with kernel domain


Logcat Unified logging method for userspace Easy to use within C/C++/Java code

Google give thousands of pages of code that use this Interesting tool to log from the target shell:

# log -hUSAGE: log [-p priorityChar] [-t tag] message

priorityChar should be one of:v,d,i,w,e

Multiple buffersmain, radio, events, system


Logcat OK main is where all my usual logs goes

and radio contain logs with radio tags..grep -rns RIL system/core/liblog/

But system ?Contain logs written to main as well but filter on framework known tags

And events ?Contain PowerManager, battery, notifications events

import android.util.EventLog;

EventLog.writeEvent(TAG, 1, log message);


Logcat Get the logs from workstation:

$ adb logcat [-b buffer_name] [-v time] [filterspecs]where filterspecs is something like:

Tag:V *:sif there is no *:s the filter does not apply at all..

Clear the device buffer:$ adb logcat [-b buffer_name] -c

Synchronize logcat with kernel log:# logcat -c ; logcat -b radio -v time > /dev/kmsg &


Logcat


Logcat#/bin/bash# logcat_color.sh: Simple but effective way to # colorize logcat in shell

adb logcat -v time $@ | while read line ; dolevel=`echo $line | sed -e "s/^[0-9|\.| |-|:|-]*//"`level=`echo ${level:0:2}`case $level in'V/') echo -e "\033[0m$line\033[0m";;'D/') echo -e "\033[34m$line\033[0m" ;;'I/') echo -e "\033[32m$line\033[0m" ;;'W/') echo -e "\033[33m$line\033[0m" ;;'E/') echo -e "\033[31m$line\033[0m" ;;*) echo -e "\033[1m$line\033[0m";;esac

done


Trace dumpsThanks to rxwen agdb.py translate this:

with: $ adb logcat | agdb.py -rin..

I/DEBUG ( 30): Build fingerprint: 'generic/generic/generic:2.3.1/GINGERBREAD/'I/DEBUG ( 30): pid: 33, tid: 450>>> /system/bin/mediaserver


Trace dumps

Make sure service debuggerd is running!

https://code.google.com/p/rxwen-blog-stuff/ source/browse/trunk/tools/agdb.py

I/DEBUG ( 30): Build fingerprint: 'generic/generic/generic:2.3.1/GINGERBREAD/I/DEBUG ( 30): pid: 33, tid: 450 >>> /system/bin/mediaserver


Build/install/refresh a libBuild:$ mmm frameworks/base/services/input/:libinputInstall: out/target/product/rp1100/system/lib/libinput.soInstall:$ adb push out/target/product/rp1100/system/lib/libinput.soRefresh:$ adb shell stop$ adb shell ps -g servicemanagerUSER PID PPID VSIZE RSS WCHAN PC NAMEsystem 68 1 904 332 ffffffff 00000000 S /system/bin/servicemanager

$ adb shell kill 68


Misc things Memory usage Environment


Memory usageHaving a root shell we can use procrank:

root@android:/ # /data/local/tmp/procrank -u PID Vss Rss Pss Uss cmdline 427 57900K 57836K 23880K 19532K com.android.launcher 286 52808K 52792K 20163K 15396K system_server 75 23904K 21504K 12528K 7104K /system/bin/surfaceflinger 474 37408K 37324K 8249K 5680K android.process.acore 76 38064K 37924K 6988K 4060K zygote... 67 480K 476K 267K 260K /system/bin/sh 1522 200K 200K 176K 172K /sbin/adbd 74 392K 388K 140K 132K /system/bin/debuggerd 84 360K 356K 127K 120K /system/bin/sdcard 1 216K 216K 152K 108K /init 62 172K 172K 124K 80K /sbin/ueventd ------ ------ ------ 189241K 137972K TOTAL


Memory usageProcrank can sort by:

VSS: All the Virtual memory addressed by the processRSS: Memory that relies into the RAMPSS: Common objects are added to process buckets proportionallyUSS: Portion of the process memory space addressed only by this process


Memory usageOn non root shell?

# su 2000 /data/local/tmp/procrank -u Error creating kernel interface -- does this kernel have pagemap?

For dalvik packages we still can use:dumpsys meminfo package_name


Memory usage# su 2000 dumpsys meminfo com.android.launcher Applications Memory Usage (kB):Uptime: 80536220 Realtime: 122556573

** MEMINFO in pid 427 [com.android.launcher] ** Shared Private Heap Heap Heap Pss Dirty Dirty Size Alloc Free ------ ------ ------ ------ ------ ------ Native 16 8 16 5472 3913 359 Dalvik 4532 10780 4028 11271 9931 1340 Cursor 0 0 0 Ashmem 0 0 0 Other dev 14196 4832 6772 .so mmap 1258 2160 508 .jar mmap 0 0 0 .apk mmap 511 0 0 .ttf mmap 5 0 0 .dex mmap 0 0 0 Other mmap 1276 20 40 Unknown 1953 940 1912 TOTAL 23747 18740 13276 16743 13844 1699

...


Shell EnvironmentDefault is defined by /init.rc

All procs forked from init inherit this env

...export PATH /sbin:/vendor/bin:/system/sbin:/system/bin:/system/xbinexport LD_LIBRARY_PATH /vendor/lib:/system/libexport ANDROID_BOOTLOGO 1export ANDROID_ROOT /systemexport ANDROID_ASSETS /system/appexport ANDROID_DATA /dataexport ASEC_MOUNTPOINT /mnt/asecexport LOOP_MOUNTPOINT /mnt/obbexport BOOTCLASSPATH /system/framework/core.jar:/system/framework/core-junit.jar:/system/framework/bouncycastle.jar:/system/framework/ext.jar:/system/framework/framework.jar:/system/framework/android.policy.jar:/system/framework/services.jar:/system/framework/apache-xml.jar...


Shell EnvironmentFrom a shell we can override the def environment at least for our forks:

$ adb push myprogram /data/local/tmp$ adb push libmy.so /data/local/tmp

# export LD_LIBRARY_PATH=/data/local/tmp:\$LD_LIBRARY_PATH

# /data/local/tmp/myprogram


Other thoughts

THROW EVERYTHING!!

HTML5 IS COMINGTizen, Ubuntu Mobile

My opinion? At least not in 2 years


Resources

http://source.android.com/All needed to start developAndroid

http://developer.android.comAll you need to develop applicationsfor Android

http://developer.android.com/about/dashboards/index.htmlUpdated infos about Android installations

http://elinux.org/images/c/c9/Android-tips-and-tricks-2010-10.pdfThanks to Tim Bird and his inspiring talk at ELCE 2010

http://developer.android.com/about/dashboards/index.htmlUpdated infos about Android installations

http://elinux.org/Android_PortalLot of non official stuffs around Android


Q/A

Thanks for your time

Questions and Answers

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