In Kotlin, there's a faster way of doing this, by using a constructor.A constructor is like a special function, and it is defined by using two parantheses () after the class name. You can specify the properties inside of the parantheses (like passing parameters into a regular function)...
var datas: String = "") { constructor() : this(0) } 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 会出现下面警告和异常 Warning:(11, 2) 警告: There are multiple good constructors and Room will pick the no-arg construct 1. 当新增加的字段时,就会编译失败,找不到 setter...
The code inside theinitblock is the first to be executed when the class is instantiated. Theinitblock is run every time the class is instantiated, with any kind of constructor as we shall see next. Multiple initializer blocks can be written in a class. They’ll be executed sequentially as ...
9.3 Class with primary constructor, 主构造器定义在类头部, 因此需要init空间做初始化 */ class KotlinClassConstructor1 constructor(name: String) { val name: String init { = name } } val kotlinClassConstructor1 = KotlinClassConstructor1("Jack") println("kotlinClassConstructor:${}") /* 9.4 Class...
Let’s see a few examples to clarify this statement. 代码语言:javascript 代码运行次数:0 运行 AI代码解释 // the derived class has no primary constructor class Derived : Base { // calling the base constructor with super() constructor(p: Int) : super() { } } // the derived class has ...
// Create Pair using constructor 类型推断也适用于更复杂的情况,例如从推断类型中推断类型。让我们使用 Kotlin 标准库的mapOf函数,并将Pair类的to方法中缀到定义map。对中的第一项将用于推断map键类型;第二项将用于推断值类型: var map = mapOf("Mount Everest" to 8848, "K2" to 4017) ...
open class SubClass : Base{ constructor(type:String) : super(type){ } final override fun doSomething() { super.doSomething() } } 7.6.2 多重继承有些编程语言支持一个类拥有多个父类,例如C++。 我们将这个特性称之为多重继承(multiple inheritance)。多重继承会有二义性和钻石型继承树(DOD:Diamond...
publicclassCharprivateconstructor():Comparable<Char>{/** * Compares this value with the specified value for order. * Returns zero if this value is equal to the specified other value, a negative number if it's less than other, * or a positive number if it's greater than other. */public...
Then theactualimplementations can pass the platform-specific delegates. SeePlatform constructorsbelow for more details on these delegates. Some platform implementations also includeFactoryclasses. These make it easier to manage multiple namedSettingsobjects from common code, or to automate some platform-spe...
如果主构造函数没有任何注解或者可见性修饰符,可以省略这个 constructor 关键字。 class Person constructor(firstName: String) { /*……*/ } class Person(firstName: String) { /*……*/ } class Person(val firstName: String = "123", val lastName: String, var age: Int) { /*……*/ } ...