Using the approach from How can I create instances of managed object subclasses in a NSManagedObject Swift extension?
you can define a generic helper method which infers the type of self
from the calling context:
extension UIView {
class func instantiateFromNib() -> Self? {
return instantiateFromNibHelper()
}
private class func instantiateFromNibHelper<T>() -> T? {
let topLevelObjects = NSBundle.mainBundle().loadNibNamed("CustomViews", owner: nil, options: nil)
for topLevelObject in topLevelObjects {
if let object = topLevelObject as? T {
return object
}
}
return nil
}
}
This compiles and works as expected in my quick test. If
MyCustomView
is your UIView
subclass then
if let customView = MyCustomView.instantiateFromNib() {
// `customView` is a `MyCustomView`
// ...
} else {
// Not found in Nib file
}
gives you an instance of MyCustomView
, and the type is
inferred automatically.
Update for Swift 3:
extension UIView {
class func instantiateFromNib() -> Self? {
return instantiateFromNibHelper()
}
private class func instantiateFromNibHelper<T>() -> T? {
if let topLevelObjects = Bundle.main.loadNibNamed("CustomViews", owner: nil, options: nil) {
for topLevelObject in topLevelObjects {
if let object = topLevelObject as? T {
return object
}
}
}
return nil
}
}