I followed the procedure according to the site: https://developer.vuforia.com/resources/dev-guide/step-3-compiling-running-vuforia-sample-app.
I tried to build ImageTargets shared library through cygwin but the displayed message is:
$ ndk-build
Android NDK: Could not find application project directory !
Android NDK: Please define the NDK_PROJECT_PATH variable to point to it.
/cygdrive/c/Users/Dimitris/Desktop/ANDROID/adt-bundle-windows-x86/android-ndk-r8e/build/core/build-local.mk:130: *** Android NDK: Aborting . Stop.
I can assure you that no empty character is to the path of my project directory.
I have located ImageTargets project into the folder : C:\Users\Dimitris\Desktop\ANDROID\adt-bundle-windows-x86\samples
So i ran the commands:
$ cd C:/Users/Dimitris/Desktop/ANDROID/adt-bundle-windows-x86/samples
and
$ ndk-build
The problem has solved!!I found the path.During the installation of Vuforia a new folder had been created in C:\Development...... bla bla bla... In fact I reinstalled everything according to Vuforia site and for the time being everything works great... thank you very much Al G...