Kotlin笔记-026枚举类

枚举类

枚举类定义:enum class

// 枚举类；枚举的父类是 Enum，不能继承其他类，只能实现其他接口
enum class Logo {
    Action1, Action2, Action3
}

fun main() {
    val act1Str: String = Logo.Action1.name // Action1
    val act1id: Int = Logo.Action1.ordinal // 0
    val act2Str: String = Logo.Action2.name // Action2
    val act2id: Int = Logo.Action2.ordinal // 1
}

枚举类定义构造器

enum class Logo2(val id: Int) {
    Action1(0), Action2(1)
}

实现接口

// 实现接口-统一实现
enum class Logo3 : Runnable {
    Action1, Action2;

    override fun run() {
        println("Kotlin")
    }
}

// 实现接口-各自实现
enum class Logo4 : Runnable {
    Action1 {
        override fun run() {
            println("Action1")
        }
    },
    Action2 {
        override fun run() {
            println("Action2")
        }
    }
}

用于分支表达式

fun main() {
    // 可用于分支表达式
    val logo: Logo = Logo.Action1

    val value = when (logo) {
        Logo.Action1 -> println("I am Action1")
        Logo.Action2 -> println("I am Action2")
        Logo.Action3 -> println("I am Action3")
    }
}

枚举的区间用法

fun main() {
    // 枚举的区间
    val range: ClosedRange<Logo> = Logo.Action1..Logo.Action2
    val r1 = Logo.Action2
    val isInRange = r1 in range
}

枚举类

枚举类定义:enum class

// 枚举类；枚举的父类是 Enum，不能继承其他类，只能实现其他接口
enum class Logo {
    Action1, Action2, Action3
}

fun main() {
    val act1Str: String = Logo.Action1.name // Action1
    val act1id: Int = Logo.Action1.ordinal // 0
    val act2Str: String = Logo.Action2.name // Action2
    val act2id: Int = Logo.Action2.ordinal // 1
}

枚举类定义构造器

enum class Logo2(val id: Int) {
    Action1(0), Action2(1)
}

实现接口

// 实现接口-统一实现
enum class Logo3 : Runnable {
    Action1, Action2;

    override fun run() {
        println("Kotlin")
    }
}

// 实现接口-各自实现
enum class Logo4 : Runnable {
    Action1 {
        override fun run() {
            println("Action1")
        }
    },
    Action2 {
        override fun run() {
            println("Action2")
        }
    }
}

用于分支表达式

fun main() {
    // 可用于分支表达式
    val logo: Logo = Logo.Action1

    val value = when (logo) {
        Logo.Action1 -> println("I am Action1")
        Logo.Action2 -> println("I am Action2")
        Logo.Action3 -> println("I am Action3")
    }
}

枚举的区间用法

fun main() {
    // 枚举的区间
    val range: ClosedRange<Logo> = Logo.Action1..Logo.Action2
    val r1 = Logo.Action2
    val isInRange = r1 in range
}