I almost missed this in my first library based project. Luckily I usually wipe a device clean for the final test before publishing and saw that when I installed the app I got two new icons in the device! In addition to the icon of the app I was testing I got an icon for the library project it was based on. On closer inspection I saw that two APKs had actually been installed. Well, that's not the result I was looking for so off to Google I went.. and discovered not many people had written about this. And none of the solutions worked for me.
Then I started thinking, the android docs says a library project can't be installed. So why was mine being installed..? Turns out the library project started life as an app, and still residing in the bin directory was an old APK which I decided to delete!
Now I get this error:
I don't know why it tries to find the APK for the library project, a bug in Eclipse perhaps? But since everything works as it should now I'm not going to spend any time digging deeper and just ignore the error. Next time I'll start the library project as a library project and see if that eliminates the problem all together.