Class and Object, Constructor - Primary and Secondary constructor in Kotlin #class #classandobject

Kotlin supports object-oriented programming with classes and objects. Objects are useful for storing data in your program. Classes allow you to declare a set of characteristics for an object. When you create objects from a class, you can save time and effort because you don't have to declare these characteristics every time. Note on Class-level Variables: Variables declared within a class but outside any function are called member properties or instance variables. Their scope is tied to the instance of the class, and they are accessible to all methods within that class. While not strictly "global," they offer a wider scope than local variables. A function that’s defined inside a class is called a member function. It’s sometimes called a method. Class and Objects: Classes are templates that allow you to create your own types of objects, and define their properties and functions. How to design your own classes? When you want to define your own class, you need to think about the objects that will be created from that class. You need to consider: * The things each object knows about itself. * The things each object can do. The things an object knows about itself are its properties. The things an object can do are its functions. A constructor runs when you instantiate an object. It’s used to define properties and initialize them. An object is sometimes known as an instance of a particular class, so its properties are sometimes called instance variables. We recommend that you declare properties as read-only (val) unless they need to be changed after an instance of the class is created. In Kotlin, a constructor is a special function used to initialize the properties of a class when you create a new instance (object) of that class. Kotlin supports two types of constructors: primary and secondary. Primary Constructors The primary constructor is the main, concise way to declare a class constructor in Kotlin. It is declared directly in the class header.Its main purpose is to initialize properties and define parameters accepted when creating an instance. Features: Location: Part of the class signature (after the class name). Keywords: The constructor keyword can be omitted if it has no annotations or visibility modifiers. Initialization: Initializing logic often goes into an init block. Secondary Constructors A secondary constructor is used when you need more complex initialization logic or want to provide multiple ways to construct an object with different parameter sets (method overloading). Features: Location: Declared inside the class body. Keyword: Uses the constructor keyword explicitly. Delegation: If a primary constructor exists, secondary constructors must delegate to the primary constructor (either directly or indirectly) using the this() keyword. How to use initializer blocks? Initializer blocks are executed when the object is initialized, immediately after the constructor is called, and they’re prefixed with the init keyword. If you’re completely certain that you can’t assign an initial value to a property when you call the class constructor, you can prefix it with lateinit. This tells the compiler that you’re aware that the property hasn’t been initialized yet, and you’ll handle it later. If you wanted to mark the temperament property for late initialization, for example, you’d use: Doing so allows the compiler to compile your code. In general, however, we strongly encourage you to initialize your properties. when you write the code the compiler secretly adds the getters and setters when the code is compiled. This means that whenever you use the dot operator to get or set a property’s value, behind the scenes its always the property’s getter or setter that gets called. Telegram Group: https://t.me/androidNinjaWarrior Guide to watch: 00:00 Introduction 00:50 Why we need to create class and object? 08:35 How to create class in kotlin? 12:50 How to create object of a class in kotlin? 18:50 How to create constructor in kotlin? 28:35 How to use init and lateinit in kotlin? 33:23 How to create secondary constructor in kotlin? 42:18 Revision of Class, Objects, Constructor, init and lateinit in kotlin. 45:33 How to get files of this kotlin tutorial? #Class #object #OOP #ClassObject #constructor #primaryConstructor #secondaryConstructor #init #lateinit #instanceVariable #memberFunction #NeedOfClass #ConstructorOverload #kotlin #KotlinCourse Disclaimer- Some content are used for educational purposes under fair use. Copyright Disclaimer Under Section 107 of the Copyright Act 1976, allowance is made for "fair use" for purposes such as criticism, comment, news reporting, teaching, scholarship, and research. Fair use is a use permitted by copyright statute that might otherwise be infringing. Non-profit, educational, or personal use tips the balance in favor of fair use. All credit for copyright material used in the video goes to the respected Owner. Thank you guys.