destructiveButtonIndex
The index number of the destructive button.
Declaration
var destructiveButtonIndex: Int { get set }Discussion
Button indices start at 0. The default value of this property is normally -1, which indicates that no destructive button has been set. However, a destructive button may be created and set automatically by the init(title:delegate:cancelButtonTitle:destructiveButtonTitle:) method. If you use that method to create a destructive button, you should not change the value of this property.