Hi,
It sounds to me like you may have imported the wrong Point class, there is a number of Point classes around in standard libraries. Check the imports at the top of your class file, you might find you have:
import android.graphics.Point;
Delete that one (assuming you're not using this Android graphics point elsewhere), and replace it with the ArcGIS Runtime SDK for Android Point class import, using a statement like this:
import com.esri.core.geometry.Point;
And then go back to your Point class declaration and you should find you now have different constructors for your Point, and the x, y parameters will be doubles. Its easy to accidentally add the wrong imports sometimes, and different IDEs have different shortcuts and commands to automate adding the imports.
Hope this helps,