Welcome to this first Android tutorial on how to make your own one finger zoom control like the one found in the Camera and Album applications in the Sony
L. Vu, K. Nahrstedt, S. Retika, and I. Gupta. Proceedings of the 13th ACM international conference on Modeling, analysis, and simulation of wireless and mobile systems, page 257--265. New York, NY, USA, ACM, (2010)