( iOS ) What is superview and what is subviews

Question

What is superview and what is subviews?

When I add this code:

[self.view addSubview:self.frontView];
// what does that mean ?

And...

@property (nonatomic, strong) IBOutlet UIImageView *frontView;
[self.frontView superview] != nil // means ?

what is in superview?

Answer 1

A superview is a view that holds other views over it and subviews are the views being held/added over a View .

Let's assume we have a view named MyView , which holds a UIButton (named loginButton ) over it. Here MyView is considered a superview for loginButton and loginButton is considered a subview of MyView .

For more, you should start from here

As per the provided code snippet.

[self.view addSubview:self.frontView];

Hence view (Controller's view) is a superview and frontView is a subview

Answer 2

"superview" means the view which holds the current one. "subviews" means the views which are holding by the curent view.

For example, you have a view (will call it as MyView) which include a button. Button is a view too (UIButton is a kind of view). So, MyView is superview for the button. Button is a subview for MyView.

Answer 3

See Apple's View Programming Guide , section View Hierarchies and Subview Management

Answer 4

subview is childview ( which is added on any view)

superview is parentview (on which subview is added)