Here is a UNofficial google api that meets your requirements and is open source.
Android Music API
This is not an official api. This library allows you to query directly the official Android server servers to search for information, search for applications, etc.
Below are the library functions.
Features:
1) You can view the market on any media or locale you want.
2) Search for applications using keywords or package name.
3) Retrieve application information using the application identifier.
4) Get comments using the application identifier.
5) Get screenshots and PNG icon.
source share