1. A computer-implemented method for providing a user interface of a native application for a portable electronic device, comprising: providing an environment for customizing the user interface using one or more custom views, wherein the one or more custom views comprise a set of user-interface components, a layout of the user-interface components, and a configuration of a user-interface component from the set of user-interface components; and enabling, via a rendering apparatus within the native application, use of the one or more custom views with the native application through the environment independently of a platform of the native application.