I found some cool android libraries the other day and decided to try some. But I'm having trouble correctly importing the library. This is the URL of the library : https://github.com/dmytrodanylyk/android-process-button I first tried importing the library to eclipse (and move the files in java directory to src directory and set the project as library) and importing the sample to eclipse and set it to use the library project (Properties-Android-Libraries). But it didn't work. The layout files said it failed to instantiate [custom widget class]. The I tried importing the .jar file to libs directory (and update the java build path) but it didn't work either. It showed errors in the java files too. I then tried copying all the java and layout files to the sample project directory and it worked. But I'm guessing that's not the way to work with 3rd party libraries. I first thought it's some error with the library but all the other libraries I tried to import to my projects faced the same problem. Can someone walk me through how to correctly import a 3rd party library to my android project?