About one in two adults and one in four teens own a smart phone in North America and use it to access online information and services. This, ever increasing, demand for mobile applications has given rise to the need for tools and methods to systematically support the design and construction of these applications. Responding to this need, we have developed WL++, a code-generation environment for mobile-application development. Using this tool, developers can create application-specific diagrams of the application's logical model and annotate them with information about the user-interface widgets appropriate for interacting with the model elements. WL++ then produces a relational back-end for storing the model data, a set of RESTful APIs for accessing and updating the back-end, and a multi-platform mobile application that relies on the IBM Worklight framework to render, interact with and store the relevant data, through the chosen widgets and APIs. In addition, a general service monitors and records the usage of the APIs and the data exchange between the application and the back-end. In this paper, we describe the WL++ cross-mobile application generation framework and we illustrate its functionality with an example.