I read about it here but I even don't know what it is?
And what's the problem if I use a global variable?
Is it a way to save variables with
let defaults = UserDefaults.standard
defaults.set("Hello World", forKey: "BeginningText")
defaults.synchronize()
so that every class can access to it?
Can someone please answer this questions?
Would be very kind!
singleton (a pretty special *****) are to make sure instance is created only once.
I frequently use it to store globals, in a class and not as individual var.
The patern is:
class Global {
class var shared : Global {
struct Singleton {
static let instance = Global()
}
return Singleton.instance;
}
var aProperty: String?
func setProperty(with s: String) {
aProperty = s
}Then, I use as follows
let x = Global.shared.aPropertyIt is often good to create func to set values and use as:
Global.shared.setProperty("Some text")Can read this to get more insight:
h ttps://cocoacasts.com/what-is-a-singleton-and-how-to-create-one-in-swift
singleton (a pretty special *****) are to make sure instance is created only once.
I frequently use it to store globals, in a class and not as individual var.
The patern is:
class Global {
class var shared : Global {
struct Singleton {
static let instance = Global()
}
return Singleton.instance;
}
var aProperty: String?
func setProperty(with s: String) {
aProperty = s
}Then, I use as follows
let x = Global.shared.aPropertyIt is often good to create func to set values and use as:
Global.shared.setProperty("Some text")Can read this to get more insight:
h ttps://cocoacasts.com/what-is-a-singleton-and-how-to-create-one-in-swift
Thank you for your answer, Claude!
Hello Claude,
I'm confused about this issue:
As soon as I make more than one variable in your example I get these bad errors:
class Global { Class 'Global' has no initializers
class var shared : Global {
struct Singleton {
static let instance = Global() 'Global' cannot be constructed because it has no accessible initializers
}
return Singleton.instance;
}
var aProperty: String?
var text: [String?]
func setProperty(with s: String) {
aProperty = s
}
func setText(with s: [String]) {
text = s
}Do you have an idea what to do?
The best solution is to make properties optional.
Note that
[String?]
is not optional.
BNut
[String]?
would be.