Input textfield, sliders, buttons etc

Well for these fancy objects, which are not easy to program from scratch, you can use this library:

http://www.sojamo.de/libraries/controlP5/

Example code:

http://www.openprocessing.org/visuals/?visualID=20726

as usual download the library, unzip, and pu this folder in the folder libraries inside the Processing folder with your sketches. In this folder there are lots of examples, buttons sliders....