Kotlin 学习记录（常变量、数据类型）

// 声明一个延迟初始化的字符串数组变量
private val mTitles : Array<String> by lazy {
arrayOf(
        ctx.getString(R.string.tab_title_android),
        ctx.getString(R.string.tab_title_ios),
        ctx.getString(R.string.tab_title_h5)
)
}

// 声明一个延迟初始化的字符串
private val mStr : String by lazy{
"我是延迟初始化字符串变量"
}

// 1. 顶层声明
const val NUM_A : String = "顶层声明"

// 2. 在object修饰的类中
object TestConst{
    const val NUM_B = "object修饰的类中"
}

// 3. 伴生对象中
class TestClass{
    companion object {
        const val NUM_C = "伴生对象中声明"
    }
}

fun main(args: Array<String>) {
    println("NUM_A => $NUM_A")
    println("NUM_B => ${TestConst.NUM_B}")
    println("NUM_C => ${TestClass.NUM_C}")
}常量声明的三种正确方式

var num16 = 0x0F
var num2 = 0b11110001
var num10 = 123

var oneMillion = 1_000_000
println("var oneMillion = 1_000_000 => var oneMillion = $oneMillion")

    var operaNum = 2

    var shlnum = operaNum shl(2)
    var shrnum = operaNum shr(2)
    var ushrnum = operaNum ushr(2)

    println(" shlOperaNum => $shlnum \n" +
            " shrOperaNum => $shrnum \n" +
            " ushrOperaNum => $ushrnum \n " )