Kotlin Lecture Notes

Introduction to Kotlin

• Kotlin is popular for Android app development.
• Can be used to build other types of applications.
• Course covers everything from basic setup to advanced topics.

Course Outline

• Basic setup and first program.
• Topics include variables, operators, loops, arrays, OOP, etc.
• Designed for beginners and experienced programmers.

Setting Up Development Environment

• Use IntelliJ IDEA, a sophisticated IDE by JetBrains.
• IntelliJ IDEA has features like syntax highlighting, error detection, and easy code execution.
• Community edition is free; Ultimate edition is paid.

Writing First Kotlin Program

• Steps from downloading IntelliJ IDEA to writing and running a simple Kotlin program.
• Main entry point is the main function.
• Use println function to print to console.

Kotlin Basics

Variables

• Declared using var (mutable) or val (immutable).
• Type inference in Kotlin.
• Example: var age: Int = 25

Data Types

• Basic types include Int, Double, String, Boolean, Char.
• Type conversions between types (e.g., toDouble, toInt).

Operators

• Arithmetic, comparison, logical operators.
• +, -, *, /, ==, !=, &&, ||.
• Operator precedence and associativity.

Control Structures

Conditional Statements

• if and else statements for branching logic.
• Relational operators to compare values.

Loops

• for, while, do-while loops for iteration.
• Use break and continue to control loop execution.

Collections

Arrays

• Fixed-size containers for elements of same type.
• Declared with arrayOf function.

Lists

• Mutable (mutableListOf) and immutable (listOf) lists.
• Lists can hold elements of the same or mixed types.

Sets and Maps

• Sets store unique items; maps store key-value pairs.
• Mutable and immutable variants available.

Object-Oriented Programming (OOP)

Classes and Objects

• Define classes to create objects with properties and methods.
• Use var and val to declare properties.
• Example: class Car(val model: String, var speed: Int)

Constructors

• Primary and secondary constructors.
• Initializer blocks for additional initialization logic.

Inheritance

• Use open keyword to make classes inheritable.
• override keyword to override methods in inherited classes.

Interfaces

• Define contracts for classes to implement.
• Classes use the interface keyword and must implement its methods.

Advanced Topics

Generics

• Enable classes and functions to operate on types specified by the user.
• Declare with <T> and specify type constraints with : T.

Coroutines

• For asynchronous programming and concurrency.
• Use suspend functions and launch builder.

Kotlin Standard Library

• Extensive library providing functions for collections, strings, and more.

Extensions

• Add functionality to existing classes without inheriting.
• Use fun keyword outside class declaration.

Kotlin and Java Interoperability

• Call Java code from Kotlin and vice versa.
• Kotlin supports null-safety to prevent NullPointerExceptions.

Best Practices

• Use immutable data structures when possible.
• Embrace Kotlin's type inference for cleaner code.
• Leverage Kotlin-specific features for concise and readable code.

Conclusion

• Kotlin is a versatile language suitable for modern Android development.
• Offers a balance of concise syntax and powerful features.