kotlin - Kotlin-循环中的销毁不起作用-无法访问var

Question

一些background:

val (name, age) = person 

此语法称为解构声明。它同时创建多个变量(更正，创建多个值)。

解构声明也可以在for循环中使用:当您说:

for ((a, b) in collection) { ... }

让我们看看我有一个列表项:

    @Parcelize
data class MyModel(
        var name: String = "",
        var is_locked: Boolean = true,
        var is_one_size: Boolean = false,
) : Parcelable

现在我已经获得了“MyModel”类的列表，并且我试图像这样遍历它们:

private fun initMyModelList(model: MutableList<MyModel>) {
 //i want to access is_locked from here with destruction but i cant ? IDE telling me the type is an int but its clearly defined as a Boolean
        for((is_locked) in model){
          //what i want to do in here is access the is_locked var of the model list and change all of them in a loop. im trying to use Destructuring in loop as a conveience. why is it not working ?
//how can i make the call signature look like this--- > is_locked = true instad of model.is_locked =true 
        }
}

我要做的就是能够在循环内调用is_locked = true而不是model.is_locked = true。如何才能做到这一点 ？

Answer 1

This syntax is called a destructuring declaration. It creates multiple variables at at the same time.

它不创建多个变量，而是捕获多个值。您正在使用值而不是引用，正如您的资料进一步说明的那样:

A destructuring declaration is compiled down to the following code:

val name = person.component1()
val age = person.component2()

最接近您想要的是此自定义扩展功能:

inline fun <E> Iterable<E>.withEach(block: E.() -> Unit) {
    forEach {
        it.block()
    }
}

像这样使用:

model.withEach {
    is_locked = true
}

在问强制性问题“为什么stdlib中不包含此内容？”之前，考虑到功能样式编程通常是关于转换不可变类型的。基本上，我在这里所做的是鼓励养成不良习惯。