view

The view stored in this property represents the root view for the view controller'€™s view hierarchy. The default value of this property is nil.

If you access this property and its value is currently nil, the view controller automatically calls the loadView() method and returns the resulting view.

Each view controller object is the sole owner of its view. You must not associate the same view object with multiple view controller objects. The only exception to this rule is that a container view controller implementation may add this view as a subview in its own view hierarchy. Before adding the subview, the container must first call its addChild(_:) method to create a parent-child relationship between the two view controller objects.

Because accessing this property can cause the view to be loaded automatically, you can use the isViewLoaded() method to determine if the view is currently in memory. Unlike this property, the isViewLoaded() property does not force the loading of the view if it is not currently in memory.

The UIViewController class can automatically set this property to nil during low-memory conditions and also when the view controller itself is finally released.

For more information about how a view controller loads and unloads its view, see View Controller Programming Guide for iOS.