If we need to use the function in all subclasses, we can declare them in the main parent class, whereas, if we want to use specific functions with different functionalities, we can do so by creating a function under any object or subclass: sealed class OsSealed(val releaseYear: Int = 0...
/*使用一行代码创建一个包含 getters、 setters、 `equals()`、 `hashCode()`、 `toString()` 以及 `copy()` 的 POJO:*/data classCustomer(val name: String, val email: String, val company: String)// 或者使用 lambda 表达式来过滤列表:val positiveNumbers= list.filter { it >0}// 想要单例?创...
public final class CoroutinesTest { public final void test() { BuildersKt.launch$default((CoroutineScope)GlobalScope.INSTANCE, (CoroutineContext)null, (CoroutineStart)null, (Function1)null, (Function2)(new Function2((Continuation)null) { int label; @Nullable public final Object invokeSuspend(@Not...
sealed class Fruit (val x: String) { // Two subclasses of sealed class defined within class Apple : Fruit("Apple") class Mango : Fruit("Mango") } // A subclass defined outside the sealed class class Pomegranate: Fruit("Pomegranate") // A function to take in an object ...
In the main() function, replace the existing println() statement with one which goes through and prints out some information you get for free with any enum class:for (day in DayOfTheWeek.values()) { println("Day ${day.ordinal}: ${day.name}") } ...
java 代码publicclassMyClass{publicstaticvoidmain(String[]a){System.out.println(demo().length());}publicstaticStringdemo(){returnnull;}}Kotlin 代码 fundemo():String?{//如果加了 ?,编译器就会允许返回null,否则直接报错returnnull}funmain(args:Array<String>){//?的意思是,如果为空,则执行前半句,...
classMainActivity:AppCompatActivity(){...} 通过上述的代码比较,Kotlin对类的写法与Java之间有以下几点区别: (1)Kotlin省略了关键字public,因为Kotlin默认类是开放的,所以不需要这个关键字。 (2)Kotlin用冒号“:”代替extends,也就是通过冒号表示继承关系。
这个makeGreet 被称之为函数引用,Function Reference,这也是 Kotlin 官方的说法。 这也说明,在 Kotlin 中,函数也可以是一个对象。 2.2.3 函数引用 在Kotlin 里,一个函数名的左边加上双冒号,它就不表示这个函数本身了,而表示一个对象,或者说一个指向对象的引用,但,这个对象可不是函数本身,而是一个和这个函数具...
public class RxJavaExample { public static void main(String[] args) { final String[] a = new String[]{"4","0","7","i","f","w","0","9"}; final Integer[] index = new Integer[]{5,3,9,4,8,3,1,9,2,1,7}; Observable.just(index) // 1. 传入 index 数组 ...
public class Main { public static void main(String[] args) { int x = 5; int y = 10; System.out.println(x + y); } } In this example, both programs do the same thing: they add two numbers and print the result. However, the Kotlin code is more concise and straightforward. This...