Everything you can display in AndEngine is an entity. The
Entity class is a basic class that stands on top of the hierarchy. The
Entity class has all the parameters the displayable objects need, such as position, scale factor, color, and so on. But on its own, it doesn't display anything.
For the former case, let's take the
Sprite class as an example. A sprite in AndEngine is a simple image rendered on a quad (a square made of two triangles). The
Sprite class extends the
Shape class, which already knows what to do when the programmer sets its height and width; therefore, the
Sprite class doesn't need to implement it. Also, the
Shape class extends the
Entity class. See the following diagram for another example:
The latter case means that you can attach one entity to another. It doesn't matter what type it is, whether it's a sprite, shape, or anything else, as long as it is...