IntelliJ Unity3d Plugin Not Finding Classes

Unity3d Plugin Cannot Find UnityPlayerActivity with IntelliJ

End of the world sale

After JetBrains had their end of the world sale at 75% off I ended up with 3 much needed tools for my game and app development. First I bought ReSharper my favorite re-factoring tool. Then I bought AppCode for iPhone development, and Finally I bought IntelliJ IDEA to replace Eclipse.

I never used IntelliJ and my only hope was that it would have better re-factoring than Eclipse. I am happy with its re-factoring capabilities however when I built the project I found that everything that worked in Eclipse failed to work in Unity3d 3.5.

When making a plugin I got the following error:

01-08 19:13:35.678: E/AndroidRuntime(9029): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.example.game/com.example.unityplugin.ExampleUnityActivity}: java.lang.ClassNotFoundException: com.example.unityplugin.ExampleUnityActivity in loader dalvik.system.PathClassLoader[/mnt/asec/com.example.game-1/pkg.apk]

Amazingly my searches returned little to know information...

Search Terms

"Unity3d IntelliJ"

"Unity3d IntelliJ Problem"

"Unity3d IntelliJ ClassNotFound"

etc..

eventually I searched: "Unity cannot find my java class"

and found this thread: http://forum.unity3d.com/threads/115426-Creating-a-JAR-for-an-Android-plugin

Which tipped me off to the last of many answers.

Solution

The reason the classes were not showing up in the Jar Artifact was the JDK I was using. I Installed IntelliJ with JDK 1.7, however eclipse uses its own compiler, which must ad-hear more to what ever 1.6 does. So I was able to fix the problem by going to File/ProjectSettings in IntelliJ (Ctrl+Alt+Shift+S) and set your SDK to 1.6. This should make the classes show up!