Get class name of object as string in Swift

Question

Getting the classname of an object as String using:

object_getClassName(myViewController)

returns something like this:

_TtC5AppName22CalendarViewController

I am looking for the pure version: "CalendarViewController". How do I get a cleaned up string of the class name instead?

I found some attempts of questions about this but not an actual answer. Is it not possible at all?

Answer 1

String from an instance:

String(describing: self)

String from a type:

String(describing: YourType.self)

Example:

struct Foo {

    // Instance Level
    var typeName: String {
        return String(describing: Foo.self)
    }

    // Instance Level - Alternative Way
    var otherTypeName: String {
        let thisType = type(of: self)
        return String(describing: thisType)
    }

    // Type Level
    static var typeName: String {
        return String(describing: self)
    }

}

Foo().typeName       // = "Foo"
Foo().otherTypeName  // = "Foo"
Foo.typeName         // = "Foo"

Tested with class, struct and enum.

Answer 2

UPDATED TO SWIFT 5

We can get pretty descriptions of type names using the instance variable through the String initializer and create new objects of a certain class

Like, for example print(String(describing: type(of: object))). Where object can be an instance variable like array, a dictionary, an Int, a NSDate, etc.

Because NSObject is the root class of most Objective-C class hierarchies, you could try to make an extension for NSObject to get the class name of every subclass of NSObject. Like this:

extension NSObject {
    var theClassName: String {
        return NSStringFromClass(type(of: self))
    }
}

Or you could make a static funcion whose parameter is of type Any (The protocol to which all types implicitly conform) and returns the class name as String. Like this:

class Utility{
    class func classNameAsString(_ obj: Any) -> String {
        //prints more readable results for dictionaries, arrays, Int, etc
        return String(describing: type(of: obj))
    }
} 

Now you can do something like this:

class ClassOne : UIViewController{ /* some code here */ }
class ClassTwo : ClassOne{ /* some code here */ }

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        // Get the class name as String
        let dictionary: [String: CGFloat] = [:]
        let array: [Int] = []
        let int = 9
        let numFloat: CGFloat = 3.0
        let numDouble: Double = 1.0
        let classOne = ClassOne()
        let classTwo: ClassTwo? = ClassTwo()
        let now = NSDate()
        let lbl = UILabel()

        print("dictionary: [String: CGFloat] = [:] -> \(Utility.classNameAsString(dictionary))")
        print("array: [Int] = [] -> \(Utility.classNameAsString(array))")
        print("int = 9 -> \(Utility.classNameAsString(int))")
        print("numFloat: CGFloat = 3.0 -> \(Utility.classNameAsString(numFloat))")
        print("numDouble: Double = 1.0 -> \(Utility.classNameAsString(numDouble))")
        print("classOne = ClassOne() -> \((ClassOne).self)") //we use the Extension
        if classTwo != nil {
            print("classTwo: ClassTwo? = ClassTwo() -> \(Utility.classNameAsString(classTwo!))") //now we can use a Forced-Value Expression and unwrap the value
        }
        print("now = Date() -> \(Utility.classNameAsString(now))")
        print("lbl = UILabel() -> \(String(describing: type(of: lbl)))") // we use the String initializer directly

    }
}

Also, once we can get the class name as String, we can instantiate new objects of that class:

// Instantiate a class from a String
print("\nInstantiate a class from a String")
let aClassName = classOne.theClassName
let aClassType = NSClassFromString(aClassName) as! NSObject.Type
let instance = aClassType.init() // we create a new object
print(String(cString: class_getName(type(of: instance))))
print(instance.self is ClassOne)

Maybe this helps someone out there!.

Answer 3

Swift 5

Here is the extension to get the typeName as a variable (work with both value type or reference type).

protocol NameDescribable {
    var typeName: String { get }
    static var typeName: String { get }
}

extension NameDescribable {
    var typeName: String {
        return String(describing: type(of: self))
    }

    static var typeName: String {
        return String(describing: self)
    }
}

How to use:

// Extend with class/struct/enum...
extension NSObject: NameDescribable {}
extension Array: NameDescribable {}
extension UIBarStyle: NameDescribable { }

print(UITabBarController().typeName)
print(UINavigationController.typeName)
print([Int]().typeName)
print(UIBarStyle.typeName)

// Out put:
UITabBarController
UINavigationController
Array<Int>
UIBarStyle

Answer 4

Swift 5.2:

String(describing: type(of: self))

Answer 5

Swift 3.0

String(describing: MyViewController.self)