反射Reflection

什么是反射？

反射就是在代码运行时，能检验程序代码本身的库

类引用Class Reference

就是将普通的类转换为KClass

使用::class

fun BaseMain() {
    var c = Student::class
    if (c is KClass) {
        println("c is KClass！")
    } else {
        println("c is not KClass!")
    }

}

class Student(name: String) {
    var name = ""
}
/**打印
c is KClass！
*/

• Object 来获取

除了利用类直接获取外，还可以用类的对象获取KClass

    var stu = Student("Nbin")
    var c2 = stu::class

    if (c2 is KClass) {
        println("the object is KClass!")
    } else {
        println("The c2 is not KClass!")
    }
/**
the object is KClass!
*/

方法引用Function Reference

有两种，一种普通调用，也可以直接用::function

fun BaseMain() {

    println(getStringNumDes(100) {
        checkZero(it)
    })
    println(getStringNumDes(-10, ::checkZero))
}

fun checkZero(num: Int): String {
    if (num > 0) return "This is positive number." else return "This is negative number!"

}

fun getStringNumDes(num: Int, check: (Int) -> String): String {
    var str = check(num)
    return "This is judge: $str"
}
/**
This is judge: This is positive number.
This is judge: This is negative number!
*/

属性引用Property Reference

看看和对象直接点号的区别

fun BaseMain() {
    var stu = Student()
    stu.name = "Nbin"

    println("This name type is '${stu::name}' and the name is ${stu::name.get()}")
    stu::name.set("Black")
    println("This name is changing to ${stu.name}")
}

class Student {
    var name = ""
}

/**打印
This name type is 'var coin.otc.com.otc.kotlin.Student.name: kotlin.String' and the name is Nbin
This name is changing to Black
*/

方法作为变量

来看一波,属性，构造方法也可以使用:: 进行调用。

fun BaseMain() {
    var pr = ::printG
    pr(arrayOf("1", "1", "222222222222222222222222222222222222222222"))
}

fun printG(vararg les: String) {
    var strs = StringBuffer()
    for (le in les) {
        strs.append(le)
        strs.append(",")
    }
    println(strs.toString())
}
/**
1,1,222222222222222222222222222222222222222222,
*/