Android Library Project (Native Plugins) not displaying properly in Inspector Window

Symptoms 

• A native Android library project located in the project folder does not show the PluginImporter window, instead it shows a default inspector window.

Cause

• Android Library Projects can only be recognized as such, if they are stored in the following folder: Assets/Plugins/Android/

Resolution

If your plugin is an Android Library Project, it needs to be placed in Assets/Plugins/Android/.

Alternatively, you can pack your library project into the binary format, as an .aar library. Aar libraries do not have this limitation and can be placed anywhere inside the Assets folder.

More Information

For more information regarding plugins, plugins for android, how to write and read them check the documentation listed below:

http://docs.unity3d.com/Manual/UpgradeGuide5-Plugins.html
http://docs.unity3d.com/Manual/PluginInspector.html
http://docs.unity3d.com/Manual/NativePlugins.html
http://docs.unity3d.com/Manual/PluginsForAndroid.html
http://tools.android.com/tech-docs/new-build-system/aar-format