Rajat Talesra gave a presentation on using Kotlin for Android development. He began with introducing himself and his background. He then discussed what Kotlin is, its advantages over Java like null safety and higher-order functions. Some issues with Java like nullability were also covered. The presentation included how to set up a Kotlin environment in Android Studio and examples of Kotlin code for Android apps, including functions, nullability, and resources for learning more.

1. KOTLIN
with
ANDROID
RajatTalesra
GDG Gandhinagar
28th October 2017
Rajat Talesra | www.wisel.in

2. Who am I?
RajatTalesra
 FounderWiseL – Edu-tech startup
 Android Developer
 Google Facilitator
 ICT Engineer
Rajat Talesra | www.wisel.in

3. About KOTLIN
 Statically typed programming language
for modern multiplatform applications
 Developed by JetBrains (Creator of Intellij)
Rajat Talesra | www.wisel.in

4. Why KOTLIN?
(1/2)
Rajat Talesra | www.wisel.in

5. Why KOTLIN?
(2/2)
Rajat Talesra | www.wisel.in

6. Issues with
Java?
 No higher functions
 No lambda support
 Nullability Problem
 Mutability Problem
Rajat Talesra | www.wisel.in

7. Advantages of
KOTLIN
 Higher functions: Function in function
 Lambda support
 Nullability issue resolved
 Immutable
 100% interoperable with JAVA
 Improves heath and performance of the app
… but adds approx 885KB to app size
Rajat Talesra | www.wisel.in

8. Starters
 Enable Kotlin Plugin
 Ctrl + Shift + A -> Search Plugins -> Install JetBrains Plugins -> Kotlin
 Convert Java File to Kotlin
 Ctrl + Shift + A -> Convert Java File to Kotlin
 Configure Kotlin in Project
 Ctrl + Shift + A -> Configure
Rajat Talesra | www.wisel.in

9. CodeStuff
Rajat Talesra | www.wisel.in

10. AndroidStudio
 EditText, Button,TextView
 Variables
 OnClickListener,Toast, Log
 Intents
 Data Models
 Methods with arguments, without arguments, etc.
Rajat Talesra | www.wisel.in

11. HighOrder
Functions
max(strings, { a, b -> a.length < b.length })
Rajat Talesra | www.wisel.in

12. Nullability
By default, Kotlin assumes that value cannot be null:
If we want to create a nullable reference, we need to create
append the question mark(?) to the type definition:
When we want to access the b reference, we must handle the null
case explicitly to avoid a compilation error because Kotlin knows
that this variable can hold null
Rajat Talesra | www.wisel.in

13. Other
methods
 let() :To execute an action only when a reference holds a non-
nullable value, we can use a let operator.
 also() : to apply some additional operation, for example logging
on every non-nullable value we can use an also()
Rajat Talesra | www.wisel.in

14. Resources
 KotlinWebsite: https://kotlinlang.org/docs/tutorials/kotlin-
android.html
 Sample Projects:
https://developer.android.com/samples/index.html?language=kotl
in
 Getting Started: https://developer.android.com/kotlin/get-
started.html
Rajat Talesra | www.wisel.in

15. Thank you
 RajatTalesra
 rajattalesra4914@gmail.com
 +91-9723124260
 www.wisel.in
Rajat Talesra | www.wisel.in