Shared on Android Taipei in 2016 Dec 19th

1. Android AIDL Concept
Charlie Tsai @ Android Study Group

2. Charlie Tsai @ Android Study Group
cha122977@gmail.com
Software Engineer

3. Agenda
• Introduction of AIDL
• Write your AIDL files
• Implementation of AIDL

4. Introduction of AIDL

5. ?AIDL?
• Android Interface Definition Language
• Main approach is IPC (Inter-Process
Communication)
• Support types:
All primitive types, CharSequence & String, List
& Map, Parcelable class

6. IPC Issue
Memories of
Process A
Process B of
Process B
X
Cannot Access
(Memory protection
by Kernel)

7. How AIDL solve IPC
issue
Memories of
Process A
Process B of
Process B
Linux Kernel & Binder Driver
Access Access

8. Write Your AIDL File
• Write *.aidl for your AIDL interface
• You can turn your Parcelable Class into AIDL
• Include if you use Other AIDL class/interface
• Note:
List will become ArrayList in another side
Map will become HashMap in another side
(WHY?)

9. AIDL Data Structure
MyData.java
MyData.aidl

10. AIDL Interface
IMyAidlInterface.aidl

11. How Parcelable Work

12. String
int
Data in memory
(order is matter)

13. Usages of AIDL

14. Export Your Service
Allow to be bound
by other App.

15. Use Other’s Service
Copy *.aidl file into your project
(Because you need to know this Interface)

16. Generated File by AIDL

17. • IInterface: Basic interface can be used for IPC
• android.os.IBinder: Core class of IPC
• Use YourInterface.asInterface(IBinder) to case IBinder
to YourInterface.
• Use IBinder.queryLocalInterface() to know if this
IBinder is in local or remote.
• If IBinder is in local, call function directly.
• If IBinder is a remote object, use transact and parcel to
call function.
Let’s see the source code…

18. Questions?

19. 固定聚會：每週三＠果子咖啡(近捷運南京復興站)
技術分享：每月底週六14:30 - 17:30
以及眾多不定期活動(ex: Workshop)

20. Thanks!