在Swift 4.1和现在的Swift 4.2中:

import Foundation

class SomeClass {
    class InnerClass {
        let foo: Int

        init(foo: Int) {
            self.foo = foo
        }
    }

    let foo: Int

    init(foo: Int) {
        self.foo = foo
    }
}

class AnotherClass : NSObject {
    let foo: Int

    init(foo: Int) {
        self.foo = foo
        super.init()
    }
}

struct SomeStruct {
    let bar: Int

    init(bar: Int) {
        self.bar = bar
    }
}

let c = SomeClass(foo: 42)
let s = SomeStruct(bar: 1337)
let i = SomeClass.InnerClass(foo: 2018)
let a = AnotherClass(foo: 1<<8)

如果你周围没有实例:

String(describing: SomeClass.self) // Result: SomeClass
String(describing: SomeStruct.self) // Result: SomeStruct
String(describing: SomeClass.InnerClass.self) // Result: InnerClass
String(describing: AnotherClass.self) // Result: AnotherClass

如果你有一个实例:

String(describing: type(of: c)) // Result: SomeClass
String(describing: type(of: s)) // Result: SomeStruct
String(describing: type(of: i)) // Result: InnerClass
String(describing: type(of: a)) // Result: AnotherClass

如果你的类型是Foo，下面的代码会在Swift 3和Swift 4中给你“Foo”:

let className = String(describing: Foo.self) // Gives you "Foo"

这里大多数答案的问题是，他们给你“Foo”。当你没有该类型的任何实例时，当你真正想要的只是"Foo"时，输入"作为结果字符串。下面是“Foo”。输入“”，就像在其他答案中提到的那样。

let className = String(describing: type(of: Foo.self)) // Gives you "Foo.Type"

如果您只想要“Foo”，则不需要使用类型(of:)部分。

斯威夫特5.2:

String(describing: type(of: self))

更新到swift 5

我们可以通过String初始化器使用实例变量获得类型名的详细描述，并创建某个类的新对象

例如，print(String(description: type(of: object)))。其中object可以是一个实例变量，如数组，字典，Int, NSDate等。

因为NSObject是大多数Objective-C类层次结构的根类，你可以尝试为NSObject做一个扩展，以获得NSObject的每个子类的类名。是这样的:

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

或者您可以创建一个静态函数，其参数类型为Any(所有类型隐式遵循的协议)，并将类名返回为String。是这样的:

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

现在你可以这样做:

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

    }
}

而且，一旦我们可以获得类名String，我们就可以实例化该类的新对象:

// 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)

也许这能帮助一些人!

你可以像这样使用Swift标准库函数_stdlib_getDemangledTypeName:

let name = _stdlib_getDemangledTypeName(myViewController)

我建议这样的方法(非常Swifty):

// Swift 3
func typeName(_ some: Any) -> String {
    return (some is Any.Type) ? "\(some)" : "\(type(of: some))"
}

// Swift 2
func typeName(some: Any) -> String {
    return (some is Any.Type) ? "\(some)" : "\(some.dynamicType)"
}

它既不使用内省，也不使用手动提取(没有魔法!)

下面是一个演示:

// Swift 3

import class Foundation.NSObject

func typeName(_ some: Any) -> String {
    return (some is Any.Type) ? "\(some)" : "\(type(of: some))"
}

class GenericClass<T> {
    var x: T? = nil
}

protocol Proto1 {
    func f(x: Int) -> Int
}


@objc(ObjCClass1)
class Class1: NSObject, Proto1 {
    func f(x: Int) -> Int {
        return x
    }
}

struct Struct1 {
    var x: Int
}

enum Enum1 {
    case X
}

print(typeName(GenericClass<Int>.self)) // GenericClass<Int>
print(typeName(GenericClass<Int>()))  // GenericClass<Int>

print(typeName(Proto1.self)) // Proto1

print(typeName(Class1.self))   // Class1
print(typeName(Class1())) // Class1
print(typeName(Class1().f)) // (Int) -> Int

print(typeName(Struct1.self)) // Struct1
print(typeName(Struct1(x: 1))) // Struct1
print(typeName(Enum1.self)) // Enum1
print(typeName(Enum1.X)) // Enum1