Concepts
Drawees
Drawees are spaces in which images are rendered. These are made up of three components, like a Model-View-Controller (MVC) framework.
DraweeView
Descended from the Android View class.
Most apps should use the SimpleDraweeView class. Place these in your application using XML or Java code. Set the URI to load with the setImageURI method, as explained in the Getting Started page.
DraweeHierarchy
This is the hierarchy of Android Drawable objects that will actually render your content. Think of it as the Model in an MVC.
DraweeController
The DraweeController is the class responsible for actually dealing with the underlying image loader - whether Fresco’s own image pipeline, or another.
If you need something more than a single URI to specify the image you want to display, you will need an instance of this class.
DraweeControllerBuilder
DraweeControllers are immutable once constructed. They are built using the Builder pattern.
Listeners
One use of a builder is to specify a Listener to execute code upon the arrival, full or partial, of image data from the server.
The Image Pipeline
Behind the scenes, Fresco’s image pipeline deals with the work done in getting an image. It fetches from the network, a local file, a content provider, or a local resource. It keeps a cache of compressed images on local storage, and a second cache of decompressed images in memory.
The image pipeline uses a special technique called pinned purgeables to keep images off the Java heap. This requires callers to close images when they are done with them.
SimpleDraweeView does this for you automatically, so should be your first choice. Very few apps need to use the image pipeline directly.