What is UIView's bounds and frame?

The UIView class defines a rectangular area on the screen and the interfaces for managing the content in that area. At runtime, a view object handles the rendering of any content in its area and also handles any interactions with that content. The UIView class itself provides basic behavior for filling its rectangular area with a background color. More sophisticated content can be presented by subclassing UIView and implementing the necessary drawing and event-handling code yourself. The UIKit framework also includes a set of standard subclasses that range from simple buttons to complex tables and can be used as-is. For example, a UILabel object draws a text string and a UIImageView object draws an image.

  

View drawing occurs on an as-needed basis. When a view is first shown, or when all or part of it becomes visible due to layout changes, the system asks the view to draw its contents. For views that contain custom content using UIKit or Core Graphics, the system calls the view’s drawRect: method. Your implementation of this method is responsible for drawing the view’s content into the current graphics context, which is set up by the system automatically prior to calling this method. This creates a static visual representation of your view’s content that can then be displayed on the screen. 

Creating view programmatically:

CGRect  viewRect = CGRectMake(10, 10, 100, 100);

UIView* myView = [[UIView alloc] initWithFrame:viewRect];

Important method in drawing the content on to the view:

drawRect: - Implement this method if your view draws custom content. If your view
does not do any custom drawing, avoid overriding this method. 

bounds: - The bounds rectangle, which describes the view’s location and size in its 
own coordinate system.

frame: - The frame rectangle, which describes the view’s location and size in its 

superview’s coordinate system.