Chapter One Android system and system architecture

1. Dalvik and ART (Android Runtime)
Application in Dalvik is like a foldable bicycle, usually folded, only when riding, it needs to be assembled.
Application in art is like a well-assembled bike that can be mounted.

2. Android Source directory structure: (one can view the Android code site: http://androidxref.com/)

　　Makefile(Describe the links between the various components of Android and instruct them to compile automatically)
　　bionic(Bionic C library)
　　bootable(Start boot-related code)
　　build(Basic development package configuration such as System compilation rules)
　　cts(Google Compatibility Test standard)
　　dalvik(Dalvik virtual machine)
　　development(Application development related)
　　external(some open source modules used by Android)
　　frameworks(Framework framework Core)
　　hardware(Vendor hardware adaptation layer HAL)
　　out(The Code output directory after compilation is complete)
　　packages(Application package)
　　prebuilt(Precompiled resources under x86 and ARM architectures)
　　sdk(SDK and Simulator)
　　system(underlying file system libraries, applications, and components)
　　vendor(Vendor custom code)

3.Android system Catalog
　　/systemAnd the /data two directories that developers are particularly concerned about.

　　/systemThe main categories are:,,,, /app /fonts /framework /lib /media , /usr etc subdirectories
For example, view the system's properties information file /system/build.prop :

[Email Protected]_umts:/system $ cat Build.prop #BeginBuild Properties # autogeneratedby buildinfo.sh Ro.Build.id=lmy47m. M003 Ro.Build.display.id=lmy47m. M003 Ro.Build.Version.incremental=8 Ro.Build.version.sdk=22 Ro.Build.Version.codename=rel Ro.Build.Version.all_codenames=rel Ro.Build.Version.Release=5.1 Ro.Build.Date=wed1910:44:PDT2015 Ro.Build.Date.utc=1440006297 Ro.build. type=User Ro.build. User=hdsplat Ro.build.host=buildlinux16 Ro.build.tags=release-keys Ro.build.flavor=falcon_gpe-User Ro.product. model=xt1032 Ro.product.brand=motorola Ro.product. NAME=FALCON_GPE Ro.product.device=falcon_umts ro.product.board=msm8226 ......

　　/dataUnder the main directory,,, and /app /data /system /misc Other subdirectories, which /data/data are the most visited directory of developers, which contains the app's data information, file information and database information, in the way of package name to distinguish between different applications.

Chapter II new contacts for Android development tools

Source of the 1.ADB command
  /system/core/toolboxAnd /frameworks/base/cmds is the source of all ADB commands and shell commands, linked here is the source path for Android 6.0.

2. Common Android Commands
  android list avdsList all created Android emulators

Android List devices
  android list targetsList all of our SDK versions available

Hujiawei-mbpr:hexoblog hujiawei$ Android list targets Available Android Targets: ---------- Id:1 or "android-8" Name:android 2.2 Type:platform API Level:8 Revision:3 SKINS:HVGA, QVGA, WQVGA400, WQVGA432, WVGA800 (default), WVGA854 Tag/abis:default/armeabi ---------- Id:2 or "android-10" Name:android 2.3.3 Type:platform API level:10 Revision:2 SKINS:HVGA, QVGA, WQVGA400, WQVGA432, WVGA800 (default), WVGA854 Tag/abis:default/armeabi ---------- id:3 or "android-15" name:android 4.0.3 Type:platform API level:15 Span class= "line" > Revision:5 SKINS:HVGA, QVGA, WQVGA400, WQVGA432, WSVGA, WVGA800 (default), WVGA854, WXGA720, WXGA800 Tag/abis:no ABIs. ----------

3. Commonly used ADB commands
　　adb push <local> <remote>, adb pull <remote> <local> (File transfer)
　　adb install xxx, adb uninstall yyy (apk install and uninstall)
　　adb usb,,, adb tcpip <port> adb connect adb devices (connect related commands)
　　adb start-server,,, adb kill-server adb reboot adb remount (re-mount the system partition to make the system partition writable)

　　adb shellRelated commands:
　　adb shell df(View system drive letter)
　　adb shell input keyevent(Analog key input, for example, adb shell input keyevent 3 Press home button)
　　adb shell input touchscreen(analog touchscreen input, e.g. adb shell input touchscreen swipe 18 665 18 350 )

　　adb shell dumpsys activity activities(View activity running status)

Hujiawei-mbpr:hexoblog hujiawei$ADB shell Dumpsys activity activities ACTIVITY MANAGERActivities(Dumpsys activity Activities) Display#0 (activities from top to bottom): Stack#0: Task ID#279 * taskrecord{2fbcccec#279 A=com.android.launcher u=0 sz=1} Userid=0 EFFECTIVEUID=U0A15 mcallinguid=Mcallingpackage=android Affinity=com.android.launcher Intent={act=android.intent.action.main Cat=[android.intent.category.home] Flg=0x10000000 Cmp=com.android.launcher/com.android.launcher2.launcher} Realactivity=com.android.launcher/com.android.launcher2.launcher autoremoverecents=False ispersistable=True numfullscreen=1 tasktype=1 mtasktoreturnto=0 rootwasreset=false mneverrelinquishidentity=true mreusetask=false activities=[activityrecord{74b834e u0 com.android.launcher/com.android.launcher2.launcher t279}] Askedcompatmode=false inrecents=true isavailable=True Lastthumbnail=null lastthumbnailfile=/data/system/recent_images/279_task_thumbnail.png Hasbeenvisible=true firstactivetime=1448539994507 lastactivetime=1448539994507 (inactive for 58s)

　　adb pm xxx(Package management information)
For example, see all the Packages

Hujiawei-mbpr:hexoblog hujiawei$ adb shell pm list packages-f Package:/system/app/youtube/youtube.apk=com. google. Android. YouTube Package:/system/priv-app/telephonyprovider/telephonyprovider.apk=com. Android. Providers. telephony Package:/system/app/mediashortcuts/mediashortcuts.apk=com. google. Android. Gallery3d Package:/data/app/com. Support. Android. designlibdemo-1/base.apk=com. Support. Android. Designlibdemo Package:/system/priv-app/velvet/velvet.apk=com. google. Android. Googlequicksearchbox Package:/system/priv-app/calendarprovider/calendarprovider.apk=com. Android. Providers. calendar Package:/data/app/com. Imooc. animatedselector-1/base.apk=com. Imooc. animatedselector Package:/system/priv-app/mediaprovider/mediaprovider.apk=com. Android. Providers. media Package:/system/priv-app/googleonetimeinitializer/googleonetimeinitializer.apk=com. google. Android. Onetimeinitializer package:/data/app/com.wandoujia-1/base.apk=com. Wandoujia Package:/system/app/bug2gostub/bug2gostub.apk=com. Motorola. bug2go Package:/data/app/com.sina.weibo.sdk.gensign-1/ Base.apk=com.sina.weibo.sdk package:/data/app/com.sohu.inputmethod< Span class= "class" >.sogou-1/base.apk=com.sohu.inputmethod .sogou package:/system/priv-app/wallpapercropper/ Wallpapercropper.apk=com.android.wallpapercropper package:/data/app/com.jredu.netease .news-1/base.apk=com.jredu.netease .news

　　adb am xxx(Activity Management Information)
For example, start an activityadb shell am start -n packageName[+className]

Start Com.wandoujia starting:intent {act=android.intent. Action. MAIN cat=[android.intent. Category. LAUNCHER] Pkg=com.wandoujia}

Chapter One Android system and system architecture