Newbie library questions

[ukimiku]

Hi all,

1) I have downloaded a library for b4a. The .zip file contains the .jar and the .xml file, and additional folders named "Objects" and "Files". Generally, do these folders have to be put into the Additional libraries folder as well?

2) How do I create a library with b4a?

3) Are the libraries created with b4a callable from low-level code on the Android device? If so, how do I as the library programmer determine which functions and routines get "exported"/exposed?

Thanks you.

Regards,

 

[NJDude]

Hi all,

1) I have downloaded a library for b4a. The .zip file contains the .jar and the .xml file, and additional folders named "Objects" and "Files". Generally, do these folders have to be put into the Additional libraries folder as well?

No, you just need to copy the .jar and .xml only

2) How do I create a library with b4a?

3) Are the libraries created with b4a callable from low-level code on the Android device? If so, how do I as the library programmer determine which functions and routines get "exported"/exposed?

Thanks you.

Regards,

Read HERE

 

[ukimiku]

Hi NJDude,

and thanks for replying. I know now that I need only the .jar and the .xml file when installing a library.

My second question is answered as well. I need some profound knowledge of JAVA and Eclipse. Eclipse is installed and understood (through programming in Python), but Java is the main reason why I chose to program in b4a instead. Well...

The third question remains open, even after ploughing through Erels clear process documentation. Suppose I have a C program. Can the C code access methods and functions from a library that was created using Erel's process? I have slight doubts because of the needed translation from java bytecode to Dalvik bytecode as performed by the mysterious "Dexer". Will this bytecode be "standard" library code on an Android device?

As limited as my java knowledge is, I think you can wrap a standard C library routine and access libraries written in C from java. Which then gives rise to the question if you can access, via a C wrapper, assembler code, say for ARM processors, from java and in turn from b4a. If that was possible, I would even venture to delve more deeply into Java, to get that chain of calls working.

I am sure this is quite special, but one of my interests lies in the field of computational arithmetic, and I would love to be able to use native machine code for (maybe distributed) number crunching on the device.

Again, thanks for replying.

Regards,

 

[warwound]

Have a read about the Android NDK: Android NDK | Android Developers, that might help answer some of your questions.

Martin.

 

[ukimiku]

Thank you.