如何在Kotlin中没有引用的情况下侦听来自另一个类的变量

interface Observer {
    fun onValueChanged(newValue: String)
}

class ObservableClass {
    private var value: String = ""
    private val observers: MutableList<Observer> = mutableListOf()

    fun setValue(newValue: String) {
        value = newValue
        notifyObservers(newValue)
    }

    fun addObserver(observer: Observer) {
        observers.add(observer)
    }

    fun removeObserver(observer: Observer) {
        observers.remove(observer)
    }

    private fun notifyObservers(newValue: String) {
        for (observer in observers) {
            observer.onValueChanged(newValue)
        }
    }
}

class ListenerClass : Observer {
    override fun onValueChanged(newValue: String) {
        // 处理变量变化的逻辑
    }
}

fun main() {
    val observable = ObservableClass()
    val listener = ListenerClass()

    observable.addObserver(listener)

    // 修改变量的值
    observable.setValue("新的值")

    observable.removeObserver(listener)
}