Rich mobile apps make mobile devices increasingly pervasive in our daily life. However, energy consumptions of mobile devices brings lots of users' frustrations. To guarantee good experiences of mobile users, we propose an energy-saving framework for mobile devices, which uses a set of coarse-grained and general-purpose energy-waste heuristics as a starting point and then smartly takes advantages of crowdsourcing intelligence to refine energy-waste related knowledge to help detect/resolve energy wastes in mobile devices. In return, summarized energy-waste related knowledge can be presented to the developers of related mobile apps and guide them to identify/fix related energy bugs. Through initial evaluations, we demonstrate the proposed framework is able to extend the lifetime of a mobile device with one full charge to a large degree (e.g., 30%-70%).