How to create extension with external SDK

[Mateja]

You need a .jar file to use custom libraries. See here:

Third-party libraries

Sometimes you have to use @UsesLibraries annotation. Most of the time this will work: Copy jar file to <root>\appinventor-sources-master\appinventor\lib\JarFolder (Create JarFolder dir in case it does not exists) Add this line to <root>\appinventor-sources-master\appinventor\components\build.xml: <copy toFile="${public.deps.dir}/NameOfJar.jar" file="${lib.dir}/JarFolder/NameOfJar.jar" />