Keeping a record of AssetBundles at Sdcard

What I've done so far :- Integrated the Unity Android Project into Eclispe so that i can use the custom android layouts thus avoiding the UnityGUI. What are my intentions:- To download the assetbundle that is selected by user (in android application ) instantiate it in unity. The implementation that i tried or have failed :- 1.tried reading the directory where the assetbundles are saved(succeeded but can't think of going anywhere from here) 2.tried reading a text file at the assetBundle Path(succeeded but can't think of further implementing it) 3.Had a look into plugins route but got confused (I am too much of noob for this!!)

for implementations 1&2 i am trying to make the url(defined at the WWW) dynamic. Making the url read from an array of paths that i got from directory or from the text file. But I cant think of a way to determine what user must have clicked in the android application and how to make a fake bridge between the android environment and unity player. Implementation 3 seems to be a great way for communication between unity and android. But the concept is too much complicated for me to swing my head around it.

What I want:- I need help in implementing any of the 3 methods above. Please Point me towards the right direction. I hope the details made it easier to understand the scenario that I am facing. I think all of the implementations listed above are possible but my lack of knowledge and experience might kill me someday :)