Best Approach to Refresh a Class [closed] - ios

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Simply i want to know what is the Best Approach to refresh a class.Like when same class is used from diff-diff section of application where we pass some data to that class ,I can do it by simply taking a global variable and change it's value from other class's But i want to know some another approach which is best suitable for this kind of Things.

Answer 1

The best way to handle this kind of structure, where the class needs to be effectively shared between other MVCs, is to make the class a singleton. This means that only one instance of a class is ever used. That way if one MVC changes the class you don't need to sync the change because every MVC uses the same instance.
To make a class a singleton you do the following
Create a static var which is an instance of the class
Make the init function private so no other class can initialise it
Eg
class Singleton {
static var shared = Singleton()
var info = "singleton info variable"
private init() {}
func doSomething() {}
}
To access the class you do the following
Singleton.shared.doSomething()
or
let singletonInfo = Singleton.shared.info

Answer 2

You have two options:
(Simplified) - Either you create a new instance and pass it on:
class MyClass {
let name: String
init(name: String) { self.name = name }
}
class MyViewController: UIViewController {
let myClass = MyClass(name: "Hello World")
func actionThatCausesSegue() {
let copyOfMyClass = MyClass(name: self.myClass.name)
self.performSegueWithIdentifier(identifier: "MySegue", sender: copyOfMyClass)
}
}
Or you can use structs:
struct MyStruct {
let name: String
init(name: String) { self.name = name }
}
class MyViewController: UIViewController {
let myStruct = MyStruct(name: "Hello World")
func actionThatCausesSegue() {
// structs are always copied when passed around.
self.performSegueWithIdentifier(identifier: "MySegue", sender: self.myStruct)
}
}
Structs are always copied, when you pass them around. Here's the explanation from the Swift Programming Language Guide by Apple:
Structures and Enumerations Are Value Types
A value type is a type whose value is copied when it is assigned to a
variable or constant, or when it is passed to a function.
You’ve actually been using value types extensively throughout the
previous chapters. In fact, all of the basic types in Swift—integers,
floating-point numbers, Booleans, strings, arrays and dictionaries—are
value types, and are implemented as structures behind the scenes.
All structures and enumerations are value types in Swift.
You can read more about the differences here.

Answer 3

It depends on the situation, but I sometimes do this for views in iOS. For example when the data model changes you want the view to update, so I implement a method in the controller called configureThingyViewWithThingy which takes the new 'thingy' and updates the view. Then whatever mechanism you're using to monitor data model changes (KVO, notifications, etc.) will call this method to reconfigure the view with the new data.