Get class name of object as string in Swift
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?
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
.
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!.
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
Swift 3.0
String(describing: MyViewController.self)