I have wondered how to get some parts of the image out of focus when using smartphone cameras (or if it can even be done). Recently found out about the concept of bokeh, and am interested in techniques to use it in image composition for cell phone cameras (the typical 8MP low aperture size digicams prevalent in recent Android devices).
Cell phone cameras don't have moving parts, such as aperture blades. So they will be working at a fixed aperture, their widest. And they'll have a very short focal length, meaning a very wide depth of field. So to get a blurred background will be very tough. You'd need to focus on a subject very close, with a background very very far, and even then, it's unlikely that you'll get bokeh as you would get from a real DSLR.
You'll have to resort to "Bokeh apps" that can add Bokeh lights to a picture you took.