Kotlin委托Delegate托管by

﹏ヽ暗。殇╰゛Y 2023-10-14 13:09 68阅读 0赞

### Kotlin委托Delegate托管by ###

import kotlin.reflect.KProperty
    
    fun main() {
        var user: String by MyDelegate()
        user = "fly"
        println(user)
    }
    
    class MyDelegate {
        private var v: String? = null
    
        operator fun getValue(thisRef: Any?, property: KProperty<*>): String {
            return "property='${property.name}' getValue ${v}"
        }
    
        operator fun setValue(thisRef: Any?, property: KProperty<*>, value: String) {
            v = value
            println("property='${property.name}' setValue -> $value")
        }
    }

> property='user' setValue -> fly  
> property='user' getValue fly

import kotlin.properties.*
    
    fun main() {
        var len: Int by Delegates.observable(0) { prop, oldValue, newValue ->
            println("$oldValue -> $newValue")
        }
    
        len = 2023
        len = 2024
    }

> 0 -> 2023  
> 2023 -> 2024

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[Delegates.observable_Kotlin_zhangphil_-CSDN_Java_Boy.java_import java.util.Observable_Java_import java.util.LinkedList_ _ _Java_ _ Observer _ Observable_zhangphil_-CSDN_Java_zhangphil_-CSDN_favicon32.ico_https_blog.csdn.net_zhangphil_article_details_132088085]: https://blog.csdn.net/zhangphil/article/details/132088085