sourceView
The view that the sheet centers itself over.
Declaration
var sourceView: UIView? { get set }Discussion
The default value is nil, which means the system centers edge-attached sheets on the edge they attach to, and centers floating sheets vertically and horizontally in the window.
To customize the sheet’s position, set a view within the view hierarchy of the presenting view controller as the sourceView of the sheet. The sheet attempts to visually center itself over this view. The system only positions the sheet within system-defined margins.