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Introduction of Android Architecture
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- 2. 2 Agenda ā¢ Introduction ā¢ AndroidArchitecture
- 3. 3 ā¢ Open sourceattracts talent across the world. ā¢ Apache license protects OEMās business. ā¢ Easy to use language and stable API improve developerās interest. ā¢ Compatibility protects Androidās Integrity. ā¢ Rich Apps inspire usersā interesting. ā¢ GMS and data protect Googleās interest. Ecosystem
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- 5. 5 Android Architecture ā¢ Application ā¢SDK & NDK ā¢ Framework & Runtime ā¢ Hal Application SDK interface layer Framework, Runtime and Libraries Hal interface layer HAL Kernel IPC IPC
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- 8. 8 Four Components Activity Content Resolver Broadcast Reciever Activity Content Resolver Broadcast Reciever Service Content Resolver Broadcast Reciever Activity Content Provider Sqlite Dataand XML Application 1 Application 2 Application 3 Send broadcast Bind or start Service using IntentSend broadcast to system Filter intent by intent filter
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- 10. 10 Android Architecture ā¢ Application ā¢SDK & NDK ā¢ Framework & Runtime ā¢ Hal Application SDK interface layer Framework, Runtime and Libraries Hal interface layer HAL Kernel IPC IPC
- 11. 11 SDK & NDK ā¢SDK API ļ¼ Android.* ļ¼ Dalvik.* ļ¼ Java.* ļ¼ Javax.* ā¢ Soft API ļ¼ Permissions ļ¼ Build Parameters ļ¼ Intent ā¢ NDK libaaudio.so, libandroid.so, libz, JNI interface, libc, libcamera2ndk.so, libdl, libEGL.so, libGLESv2.so, libGLESv3.so, libicuuc.so, libjnigraphics.so, libm.so, libRS.so, libstdc++, libvulkan.so ā¦ SDK interface layer Framework Application SDK interface layer Application IPC IPC Client Sever Function service Function service
- 12. 12 Android Architecture ā¢ Application ā¢SDK & NDK ā¢ Framework & Runtime ā¢ Hal Application SDK interface layer Framework, Runtime and Libraries Hal interface layer HAL Kernel IPC IPC
- 13. 13 Framework ā Typeof Services Service Type Example Process Function Crash recovery System Java Services AMS/PMS/UMS/W MS/DMS/CMS/LMS /ā¦ SystemServer Provide critical system services Restart by system System Native Services MediaServer/Rild/A udioflinger/surfacefli nger/logd/adbd/deb uggerd/.. Dedicated process Provide critical system services Restart by system APK Services KeyGuardServices Dedicated process Provide application level services Restart by app itself.
- 14. 14 System Services Registerand Query Running in different processes ServiceManager AMS UMS PMS WMS DMS CMS LMS ... adbd debuggerd rild logd mediaserv er surfaceflin ger audiofling er Native service Daemons Java system services Client Components 1 AddService(IPC) 2 getService(IPC) 3 Call the service provied by UMS Running in system server process
- 15. 15 APK1 Client Components 2 Send Intentto start or bind a service APK2 ServiceRecor d List PackageManager Service SystemServer 3 Call the service provied by APK1 APK services Register and Query APK will define some filter to declare which intent its services will proceed. 1 PMS will parser all APK when it is installed or system boot time to get services information APK will define some filter to declare which intent its services will proceed. PMS will be responsible for start APK1 if APK1 is not started
- 16. 16 Bionic ā¢ Developed byGoogle ā¢ BSD license ā¢ Faster and smaller ā¢ No compatibility with GUN libc ā¢ Special function for Android, such as getprop
- 17. 17 DALVIK vs ART ā¢Installation Time ā¢ Storage Usage ā¢ Performance ā¢ Battery
- 18. 18 Memory āNative Allocator Application SystemRuntime System Kernel Memory Allocator Process Virtual Address Space Map Area Heap Area malloc/calloc/realloc Unit Unit Unit Unit brk/sbrkmmap/munmap free
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- 20. 20 From Java Methodto Native Method Function type info is stored in Dex/OAT file
- 21. 21 Process and Thread JavaAPK NDK APK zygote Java process Native Daemon Framework App Ā· Thread Ā· Thread Ā· Ā· Ā· Fork Process ProcessProcessProcess Fork Process
- 22. 22 System Boot up Willparser init.rc to start all daemons and zygote Partitions will be mounted and verified one by one Init process creates daemons according to some stages: init- >boot->fs->data
- 23. 23 Init Fork Start Linker Load ELFand depended lib Zygote Process Create Heap Init Art Vm in libart.so Create Threads Start Jit Start GC Preload classes Preload drawable resource Preload libraries Enter loop to wait for incoming request Fork request to start system server Split heap into two heaps named zygote and active Start First Java Process - Zygote Create one heap named zygote using Ashmem First fork request will trigger the heap split action to improve GC performance 3000+ class and 400+ drawable will be loaded in zygote so that they can be shared across all java processes Create GC and other threads
- 24. 24 Android Architecture ā¢ Application ā¢SDK & NDK ā¢ Framework & Runtime ā¢ Hal Application SDK interface layer Framework, Runtime and Libraries Hal interface layer HAL Kernel IPC IPC
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- 27. 27 Sensor client Vibrat or c Power client Init ServiceManager Zygote System_server vold sufaceflinger mediaserver client client Sensor hal process HALServiceManag er Powerhal process audio hal process IPC IPC IPC HAL Treble Detailed Architecture HalServiceManger will be responsible for maintaining all Hal service IPC is used to communicate from Hal Client to Hal Service
Editor's Notes
- #5Ā Portability Easy Update Multiple products support Car IVI Android Auto Android TV Android wear Tablet Phone