Android - app versioning, updates

I am implementing an app, which will be updatable by downloading new version from the web. I wonder if there is way, how to download e.g. A.apk from app called A and then evoke a new开发者_C百科 instalation with new downloaded version of app A? My next question, is there any way how to "unpack" downloaded apk to get info about it's app version?

Thanks

Refer to following link

http://www.anddev.org/viewtopic.php?p=23928

Take a look here for how to download and install an app.

As for detecting the version of an apk that is not installed, you could try looking at getPackageArchiveInfo from the PackageManager documentation, but you probably also want to maintain a small database or reference on your web server that indicates the package version to make the update checks quicker.