Export the Eclipse project from Eclipse as a Gradle project.
Go to the welcome to android studio window in android studio.
Click on Import Non android studio project.
Locate the project that you exported from eclipse, expand it and select the build.gradle file and click ok.
Copy the vuforia.jar file from the vuforia sdk.
Right click on the project in android studio and click on Show in Explorer option.
Locate the libs folder and paste the copied vuforia.jar file.
Make a folder lib ( NOTE: it is not libs) in the same structure as APK file.
make another folder armeabi inside lib folder.
Copy .so files and paste it inside armeabi folder. and zip the lib folder into lib.zip
Rename the lib.zip to armeabi.jar
Include the armeabi.jar inside libs folder.
Then clean build and run the project.
reference: http://stackoverflow.com/questions/16683775/include-so-library-in-apk-in-android-studio