Static vs class functions/variables in Swift classes?
The following code compiles in Swift 1.2:
class myClass {
static func myMethod1() {
}
class func myMethod2() {
}
static var myVar1 = ""
}
func doSomething() {
myClass.myMethod1()
myClass.myMethod2()
myClass.myVar1 = "abc"
}
What is the difference between a static function and a class function? Which one should I use, and when?
If I try to define another variable class var myVar2 = "" , it says:
Class stored properties not yet supported in classes; did you mean 'static'?
When this feature is supported, what will the difference be between a static variable and a class variable (ie when both are defined in a class)? Which one should I use, and when?
(Xcode 6.3)
static and class both associate a method with a class, rather than an instance of a class. The difference is that subclasses can override class methods; they cannot override static methods.
class properties will theoretically function in the same way (subclasses can override them), but they're not possible in Swift yet.
I tried mipadi's answer and comments on playground. And thought of sharing it. Here you go. I think mipadi's answer should be mark as accepted.
class A{
class func classFunction(){
}
static func staticFunction(){
}
class func classFunctionToBeMakeFinalInImmediateSubclass(){
}
}
class B: A {
override class func classFunction(){
}
//Compile Error. Class method overrides a 'final' class method
override static func staticFunction(){
}
//Lets avoid the function called 'classFunctionToBeMakeFinalInImmediateSubclass' being overriden by subclasses
/* First way of doing it
override static func classFunctionToBeMakeFinalInImmediateSubclass(){
}
*/
// Second way of doing the same
override final class func classFunctionToBeMakeFinalInImmediateSubclass(){
}
//To use static or final class is choice of style.
//As mipadi suggests I would use. static at super class. and final class to cut off further overrides by a subclass
}
class C: B{
//Compile Error. Class method overrides a 'final' class method
override static func classFunctionToBeMakeFinalInImmediateSubclass(){
}
}
Regarding to OOP , the answer is too simple:
The subclasses can override class methods, but cannot override static methods.
In addition to your post, if you want to declare a class variable (like you did class var myVar2 = "" ), you should do it as follow:
class var myVar2:String {
return "whatever you want"
}
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