Kotlin tutorial
Kotlin is a statically typed programming language that runs on the Java virtual machine, known as the Android world Swift designed, developed and open source by JetBrains .
Kotlin can be compiled into Java bytecode or into JavaScript, making it easyto run on devices without JVM.
In Google I Dot O 2017, Google announced Kotlin become the official development language of Android.
My first Kotlin program
Kotlin program files to .kt the end, such as: hello.kt 、 app.kt .
Simplest version
package hello // Optional Baotou
fun main(args: Array<String>) { // A package level visible
function that accepts an array of strings as parameters
println("Hello World!") // Semicolons can be omitted
}
object-oriented
class Greeter(val name: String) {
fun greet() {
println("Hello, $name")
}
}
fun main(args: Array<String>) {
Greeter("World!").greet() // Creating an object without the new keyword
}
Why choose Kotlin?
Simplicity: greatly reduces the amount of boilerplate code.
Security: avoid errors of the entire class, such as null pointer exceptions.
Interoperability: take full advantage of existing libraries of JVM, Android,and browsers.
Tool-friendly: can be built with any Java IDE or using the command line.