CODEWITHSUNDEEP
androidjava-native-interfaceswigandroid-ndk
F.L.
F.L.

Reputation: 559

Best way to build complex native + java libraries with Android SDK+NDK

I am building a multi-platform SDK for real time 3D applications. This SDK is programmed in C++ and works under Windows, Apple's iOs, MacOS, Linux and Android.

The project structure is complex, it consists in 3 native C++ static libraries, linked with some external static libraries in a complete shared library. This is very simple under all the managed OSes, except for Android.

The major problem in Android is bi-directional communication/calls between native code and Java code. I got this solved some time ago using SWIG to wrap the shared library's classes. To achieve that I wrote our my own build scripts (Makefiles) to handle native compilation with the ndk r4, swig code generation, java pre-compilation and jar creation.

Lately we added some callback/listener classes in the C++ layer, that we wanted to be derivable/overloadable in Java, for this we used SWIG's directors feature. But it appears that it needs JNI features (weak global references) that were not in the NDK r4b. So we need to switch to a newer Android NDK (r6b) that has these features. But since our custom build scripts were written for NDK r4b they won't work anymore.

My concern is to have everything built properly through Android's NDK/SDK (eventually through Eclipse) with Android.mk files so we don't have to rewrite everything from scratch each time we switch to a new NDK.

I'd like to know if there is a way to manage such complex project structure with standard Android.mk, ndk-build, ant and eclipse (including the SWIG part). And if so, how ?

Don't hesitate to ask for precisions, I am not sure I am being really clear.

Any help greatly appreciated.

Florent Lagaye.

Upvotes: 3

Views: 2665

Answers (2)

F.L.
F.L.

Reputation: 559

What we ended doing is writing specific rules in the Android.mk file to manage swig interface generation.

Remember to add the generated c++ source to the list of source files before including BUILD_STATIC_LIB or BUILD_DYNAMIC_LIB, and to instruct swig to generate the java source in folder accessible by your Android java project.

Upvotes: 0

ClashTheBunny
ClashTheBunny

Reputation: 251

I've been looking for a similar thing and, although I haven't figured it out yet, there is a good example with building gstreamer on Android.

http://cgit.collabora.com/git/user/derek/androgenizer.git/

It supposedly works with any libtoolized application.

Here is the directions for how to build:

http://gstreamer.freedesktop.org/wiki/GstreamerAndroid_InstallInstructions

Upvotes: 2

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