class Log { constructor(data: String) { // some code } constructor(data: String, numberOfData: Int) { // some code } } Here, the Log class has two secondary constructors, but no primary constructor. You can extend the class as: class Log { constructor(data: String) { // code }...
2. Primary Constructor The first way to create an object in Kotlin is by using a primary constructor. This is a part of the class header.Parameters might also be class fields, which we place after the class declaration. Let’s take a look at a basic class declaration, with two properties...
Now let's see one example with two secondary constructors:Open Compiler class Person{ // Member Variables var name: String var age: Int var salary:Double // First Secondary Constructor constructor ( _name: String, _age: Int) { this.name = _name this.age = _age this.salary = 0.00 ...
Here's an example: class Lamp { // property (data member) private var isOn: Boolean = false // member function fun turnOn() { isOn = true } // member function fun turnOff() { isOn = false } } Here, we defined a class namedLamp. ...
constructor(name: String) : this(name, 0) { println("A person named $name with age 0 is created.") } } 成员属性与方法:类可以包含属性和方法。属性有val(只读)和var(读写)两种类型。方法的定义与普通函数类似,使用fun关键字。 class Circle(val radius: Double) { ...
private constructor(builder: Builder) : this(builder.model, builder.year) class Builder { var model: String? = null private set var year: Int = 0 private set fun model(model: String) = apply { this.model = model } fun year(year: Int) = apply { this.year = year } ...
扩展名为.class的文件包含 Java 字节码 扩展名为.dex的文件包含 Dalvik 字节码 扩展名为.apk的文件包含AndroidManifest文件、资源和.dex文件 对于纯 Kotlin 项目,只会使用 Kotlin 编译器,但 Kotlin 也支持跨语言项目,在这种情况下,将同时使用两个编译器来编译 Android 应用程序,并且结果将在类级别合并。
data class Salary(var base: Int = 100){ override fun toString(): String = base.toString() } operator fun Salary.plus(other: Salary): Salary = Salary(base + other.base) operator fun Salary.minus(other: Salary): Salary = Salary(base - other.base) ...
(a:Int, b:Int) :this() { println("Secondary Constructor With Two Parameter [$a, $b]") } }//Main Function, Entry Point of Programfunmain(args:Array<String>){//Create instance of class , with Primary ConstructorConstructorOverloading(100)//Create instance of class,//with no argument ...
Kotlin允许开发者在类中定义多个构造函数,以满足不同的初始化需求,这是次构造函数(constructor)存在的原因之一。 classPerson(valname:String){varage:Int=0constructor(name:String,age:Int):this(name){this.age=age}} 如上所示,如果类有一个主构造函数,每个次构造函数需要委托给主构造函数, 可以直接委托或者通...