Why you should starting programming in Kotlin for Android Some might think that Kotlin is new. I will demonstrate Kotlin history, who is behind it, and why is it a must to learn. With some links and good references This slides were conducted in GDG 6 October Google i/o event

1. Kotlin for Android
Prepared by Shady Selim
For GDG 6 October Google I/O 17 Event
On 8/7/2017

2. Speaker Bio
• Official Google Speaker
• GDG Helwan Founder & Leader
• Mobile & Web Evangelist
• Technology savvy
• Think tank, Father
• UI/UX freak
• Leader & Mentor
www.linkedin.com/in/shadyselim/
@dr_Shady_Selim
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3. Who created Kotlin?
• IntelliJ IDEA
• PhpStorm
• ReSharper
• PyCharm
• RubyMine
• … others
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4. What is Kotlin?
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5. Why Kotlin Now?
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6. 6

7. Is Kotlin Really new?
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8. Why Should I care!!?
• Statically typed programming language targeting the JVM
• Support for functional and OO paradigms
• Pragmatic, safe, concise, great Java interop
• Free and open-source
• Drastically reduce the amount of boilerplate code
• Lambda expression
• Avoid entire classes of errors such as null pointer exceptions
• Java 9 is …
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9. The Strengths of Kotlin
• Modeling the data of your application concisely and expressively
• Creating reusable abstractions using functional programming
techniques
• Creating expressive domain-specific languages
• Java interop ensures that all existing Java frameworks can be used
• No rewrite required to start using Kotlin in existing codebase
• Existing investment is fully preserved
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10. Java Model Example
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public class Customer {
private String name;
private String email;
private String company;
public Customer(String name) {
this(name, "", "");
}
public Customer(String name, String email) {
this(name, email, "");
}
public Customer(String name, String email, String company) {
this.name = name;
this.email = email;
this.company = company;
}

11. Java Model Example, cont.
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public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}

12. Java Model Example, cont.
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public String getCompany() {
return company;
}
public void setCompany(String company) {
this.company = company;
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
Customer customer = (Customer) o;
if (name != null ? !name.equals(customer.name) : customer.name != null) return false;
if (email != null ? !email.equals(customer.email) : customer.email != null) return false;
return company != null ? company.equals(customer.company) : customer.company == null;
}

13. Java Model Example, cont.
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@Override
public int hashCode() {
int result = name != null ? name.hashCode() : 0;
result = 31 * result + (email != null ? email.hashCode() : 0);
result = 31 * result + (company != null ? company.hashCode() : 0);
return result;
}
@Override
public String toString() {
return "Customer{" +
"name='" + name + ''' +
", email='" + email + ''' +
", company='" + company + ''' +
'}';
}
}

14. Kotlin Model Example, cont.
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data class Customer(var name: String,
var email: String = "",
var company: String = "")

15. Do you like reactive programming?
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16. You will not miss your frameworks or libraries
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17. You will not miss your frameworks or libraries
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18. kotlin.link
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19. Resources
• https://kotlinlang.org/
• https://m.signalvnoise.com/kotlin-its-the-little-things-8c0f501bc6ea
• https://www.jetbrains.com/
• https://www.slideshare.net/intelliyole/kotlin-why-do-you-care
• https://github.com/ReactiveX/RxKotlin
• https://spring.io/blog/2016/02/15/developing-spring-boot-
applications-with-kotlin
• https://www.slideshare.net/makingx/spring-kotlin
• https://kotlin.link/
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20. Questions!?
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