针对Android中的各种屏幕尺寸进行编程

I'm using the Canvas and the SurfaceView. I've explicitly mentioned the coordinates for various objects and fonts on the screen. The app runs perfectly on Samsung Galaxy S Advance but the objects are out of scope on smaller screens such as that of Samsung Galaxy Fit or Pop. How do i make it compatible for all screen sizes and pixel densities. Using dpis seems out of the question as I'm not using any xml layouts.I'm using the Canvas and the SurfaceView. I've