Compose Camp - Unit 1 (1).pptx

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Compose Camp
Android Basics with Compose:
Unit 1
Nishant Khandhar

Compose Camp is a hands-on introduction to
learning how you can build Android apps with
Jetpack Compose.
What is Compose Camp?

● Basic computer literacy
● Basic math skills
● Computer & headphones
● Internet connection
● Android Studio
Prerequisites

● Build your first Android apps
● Set up Android Studio on your computer
● Learn the basics of the Kotlin programming language
● Learn Jetpack Compose
● Discover resources to continue learning
Compose Camp Learning Objectives

INDEX
1. Introduction to Kotlin Playground.
2. Variables and Data types.
3. Functions in Kotlin.
4. Quiz

Kotlin Playground
Write and run Kotlin code in
the browser.

In computer programming, there's the
concept of a variable, which is a
container for a single piece of data.
You can envision it as a box that
contains a value. The box has a label,
which is the name of the variable. By
referring to the box by its name, you
have access to the value it holds.
Variables

years old
Variable
s
name age
My name is $name,and I am $age
“ALEX” 20

Variable
s
Name value: Meghan
Age value: 28
Output:
My name is Meghan and
I am 28 years old
Name value: Janet
Age value: 49
Output:
My name is Janet and I
am 49 years old
name age
My name is and I am years old

Basic data types
Kotlin Data type What kind of data it can contain Example literal values
String Text
“Add contact”
“Search”
Int Whole integer number
32
-59873
Double Decimal number
2.0
-37123.9999
Float
Decimal number (less precise than a Double).
Has an f or F at the end of the number.
5.0f
-1630.209f
Boolean
true or false. Use this data type when there
are only two possible values.
true
false

val keyword
Use when you expect the variable value will
not change.
Example: name
var keyword
Use when you expect the variable value can
change.
Example: age
Defining a variable
Use the assignment operator (=) to
assign a value to a variable either
during declaration of the variable or
updating the variable.

Defining a variable
Variables start with a var or
val
keyword.
fun main() {
val name: String = "Meghan"
var age: Int = 28
}

Defining a variable
All variables must have a name.
fun main() {
var age: Int = 28
}

Defining a variable
Data type is the type of data
that the variable holds.
fun main() {
var age: Int = 28
}

Defining a variable
The initial value is the value that
is stored in the variable.
fun main() {
var age: Int = 28
}

Functions
A function is a segment of a program that
performs a specific task.
You can have many functions in your program
or only a single one.
The main() function doesn’t actually get called
anywhere in your code; the Kotlin compiler uses
it as a starting point.

Defining a function
Functions begin with the fun
keyword followed by
function name and
parentheses and curly
braces.
fun namer () {
}
fun main() {
println(“Hello World”)
}
fun helloWorld () {
}

Defining a function
Functions have a name so that
they can be called.
fun displayIntroduction() {
}

fun helloWorld () {
println(“Happy Birthday, Alex”)
println(“You are now 20 years old”)
}
Defining a function
Functions need a set of parentheses
after the function name in order to
surround the function inputs.

Defining a function
The curly braces make up the
function body and contain the
instructions needed to execute
a task.
}

Putting it together
// We will fill this out!
}
Output:
Hi I’m Meghan and I am 28 years old

Putting it together
val name : String = "Meghan"
val age : Int = 28
println("Hi I'm $name and I am $age years old")
}

Putting it together
fun main() {
displayIntroduction()
}
val name : String = "Meghan"
val age : Int = 28
println("Hi I'm $name and I am $age years old")
}
Output:
Hi I’m Meghan and I am 28 years old

Returning in a function
We can return an output from a
function as per its defined output
datatype.
fun displayIntroduction() : String {
return “HelloWorld”;
}

Parameters of a function
We can pass extra information into
a function via parameters which
are declared between the
parentheses.
fun add(n1 : Int, n2 : Int) {
return n1 + n2
}

Parameters of a function
These parameters can also have
default values.
fun add(n1 : Int = 0, n2 : Int = 0) {
return n1 + n2
}

Arguments of a function
While calling a function in another
function, the values we pass to the
parameters defined are known as
Arguments.
fun main() {
var a : Int = 2
var b : Int = 3
println(add(a, b))
}

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Compose Camp - Unit 1 (1).pptx

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