Smartphones come equipped with multiple radios for cellular data communication such as 4G LTE, 3G, and 2G, that offer different bandwidths and power profiles. 4G LTE offers the highest bandwidth and is desired by users as it offers quick response while browsing the Internet, streaming media, or utilizing numerous network aware applications available to users. However, majority of the time this high bandwidth level is unnecessary, and the bandwidth demand can be easily met by 3G radios at a reduced power level. While 2G radios demand even lower power, they do not offer adequate bandwidth to meet the demand of interactive applications; however, the 2G radio may be utilized to provide connectivity when the phone is in the standby mode. To address different demands for bandwidth, we propose GreenTouch, a system that dynamically adapts to the bandwidth demand and system state by switching between 4G LTE, 3G, and 2G with the goal of minimizing delays and maximizing energy efficiency. GreenTouch associates users' behavior to network activity through capturing and correlating user interactions with the touch display. We have used top applications on the Google play store to show the potential of GreenTouch to reduce energy consumption of the radios by 10%, on average, compared to running the applications in the standard Android. This translates to an overall energy savings of 7.5% for the entire smartphone.