An example of a multi-platform library using JUCE
The JUCE project, Android and Windows bindings were originally written by Fabian Renn (@hogliux).
The example was presented as part of a workshop at the Audio Developers Conference 2018.
The iOS version creates a .dylib. Dynamic Libraris are not allowed by Apple for apps submitted to the App Store. They need to be wrapped in a Framework. JUCE currently does not support creating Frameworks. Probably a script could be made to create the correct folder structure for it to be recognised as a Framework. TBC
On Android, if you have proguard set for release builds, it is very likely that it will obfuscate your Java code resulting in crashes when the C++ code can't find a Java method or class member. Adding the following to your proguard-rules.pro should fix the issue:
-keepclasseswithmembernames,includedescriptorclasses class * {
native <methods>;
}
-keepclassmembers class com.mycompany.myapp.MyNativeWrapperClass {
long cppCounterpartInstance;
}