oneway in *.aidl

1.

The oneway keyword means that if that call results in an IPC (i.e. the caller and callee are in different processes) then the calling process will not wait for the called process to handle the IPC. If it does not result in an IPC (i.e. they're both in the same process), the call will be synchronous. It's an unfortunate detail that simplifies the implementation of binder IPC a lot. If they're in the same process, the call is just a regular java method call.

2.

It means methods must all have void return value (return nothing). 

 明白这些后，还要在 frameworks/base/Android.mk加上这个aidl文件，才能mmm过去 。