Spreading more than twice as fast as PCs, smartphones are quickly becoming the primary mean for Internet access. However, smartphones today are still constrained by limited computation resources such as CPU, memory and battery. In this paper, we present a framework that automatically offloads heavy back-end tasks of a regular standalone Android application to an Android virtual machine in the cloud. This framework can be deployed in the application layer without modifying the underlying Android platform. It also features three metrics that consider total response time, energy consumption and remaining battery life in deciding whether a task should be offloaded.