bean.java

public class Person{
    private String name;
    private int age;

    public Person(String name, String age){
        this.name = name;
        this.age = age;
    }

    public String getName(){ 
        return this.name;
    }
    
    public int getAge(){
        return this.age;
    }
}

KotlinFuncExtencion.kt

fun ImageView.loadImage(url: String?){
    if(url != null){
        Glide.with(this.context)
                .load(url)
                .fitCenter()
                .into(this)
    }
}

myImageView.loadImage(“!insert an url here!”)

list.java

List people = new ArrayList<Person>();
people.add(new Person(“Armando”,35));
people.add(new Person(“Erik”,26));
people.add(new Person(“Adrian”,30));

forEach(Person person: people){
  if(person.getName().equals(“Erik”)){
   return person;			
  }
} 

list.kt

val people = listOf<Person>(Person("Adrian", 30), Person("Erik",26), Person("Armando", 35))
val person = people.find { it.name == "Erik" }
println(person)

map.kt

val numberList = listOf(1, 2, 3, 4, 5)
val squared = list.map( i -> i * i)
assertTrue(squared.containsAll(listOf(1,4,9,16,25)))
squared.forEach { println(it) }

maps.kt

val numberList = listOf(1, 2, 3, 4, 5)
val squared = list.map( i -> i * i)
assertTrue(squared.containsAll(listOf(1,4,9,16,25)))
squared.forEach { println(it) }

MyActivity

d

MyActivity.java

public class MyActivity extends AppCompatActivity{
  @Override
  public void onCreate(Bundle saveInstanceState){
	  super.onCreate(saveInstanceState);
	  setContentView(R.layout.main_activity);
	  TextView myTextView = (TextView) findViewById(R.id.my_textview);
	  myTextView.setText(“¡Hola Android!”);
  }
}

MyActivity.kt

class MyActivity : AppCompatActivity{
		override fun onCreate(saveInstanceState:Bundle){
			super.onCreate(saveInstanceState);
			setContentView(R.layout.main_activity);
			my_textview.text = “¡Hola kotlin!”
		}
}

MyActivityAE.kt

class MyActivity : AppCompatActivity{
		override fun onCreate(saveInstanceState:Bundle){
			super.onCreate(saveInstanceState);
			setContentView(R.layout.main_activity);
			my_textview.text = “¡Hola kotlin!”
		}
}

MyActivityKAE.kt

class MyActivity : AppCompatActivity{
  override fun onCreate(saveInstanceState:Bundle){
	  super.onCreate(saveInstanceState);
	  setContentView(R.layout.main_activity);
	  val myTextView = findViewById(R.id.my_textview) as TextView;
	  myTextView.text = “¡Hola kotlin!”}
}

NullSafety.kt

var message : String? = null

fun sayHello(message:String?){
		if(message != null){
			println(message)
		}
}

persona.kt

// Clase declarada por en su forma completa
class Persona constructor(name:String, age: Int){
  val name = name
  var age = age
}

// Clase simplificada
class Persona(val name: String, var age: Int)

// Data class
data class Persona(val name: String, var age: Int)