6Subclassing UIView
In previous chapters, you’ve created several views: a UIButton, a UILabel, etc. But what exactly is a view?
- A view is an instance of a UIView or one of its subclasses.
- A view knows how to draw itself on the application’s window.
A view exists within a hierarchy. The window (an instance of UIWindow) is a view and the root of the hierarchy. It has subviews (that appear on the window). Those views can also have subviews.
- A view handles touch events.
In this chapter, you are going to create your own UIView subclass that fills the screen with concentric circles, as shown in Figure 6.1. You will also learn how to draw text and enable scrolling and zooming.
Figure 6.1 View that draws concentric circles
Creating a Custom View ...
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