Layers in the ArcGIS API for Flex
There are various types of layers to work from when developing in the ArcGIS API for Flex. Layers is a term used in the API reference that can be seen analogous to services. Which type of layer (service) you choose depends on the type of functionality needed.
All layers derive from the Layer base class.
Types of Layers (Services) in the ArcGIS API for Flex