Swift3中的Array内存地址和关联对象的问题
直接用OC的关联对象
空数组
//
// ViewController.swift
// SwiftRunner
//
// Created by Ferris on 2018/1/27.
// Copyright © 2018年 Ferris. All rights reserved.
//
import UIKit
var objc_associate_ket_array:UInt8 = 0
var objc_asssciate_key_object:UInt8 = 1
extension Array{
var fg_identify:String{
set{
objc_setAssociatedObject(self, &objc_associate_ket_array, newValue, .OBJC_ASSOCIATION_RETAIN_NONATOMIC)
}
get{
if let rs = objc_getAssociatedObject(self, &objc_associate_ket_array) as! String?{
return rs
}else{
return "没有关联对象"
}
}
}
}
extension NSObject{
var fg_tag:String{
set{
objc_setAssociatedObject(self, &objc_asssciate_key_object, newValue, .OBJC_ASSOCIATION_RETAIN_NONATOMIC)
}
get{
return objc_getAssociatedObject(self, &objc_asssciate_key_object) as! String
}
}
}
class ViewController: UIViewController {
let object_a = NSObject()
let object_b = NSObject()
let object_c = NSObject()
var array_a:[NSObject] = []
var array_b:[NSObject] = []
var array_c:[NSObject] = []
override func viewDidLoad() {
super.viewDidLoad()
object_a.fg_tag = "a"
object_b.fg_tag = "b"
object_c.fg_tag = "c"
array_a.fg_identify = "a"
array_b.fg_identify = "b"
array_c.fg_identify = "c"
// Do any additional setup after loading the view, typically from a nib.
}
override func viewDidAppear(_ animated: Bool){
super.viewDidAppear(animated)
print("object_a = \(object_a.fg_tag)")
print("object_b = \(object_b.fg_tag)")
print("object_c = \(object_c.fg_tag)")
print("array_a = \(array_a.fg_identify)")
print("array_b = \(array_b.fg_identify)")
print("array_c = \(array_c.fg_identify)")
}
}输出结果如下
object_a = a
object_b = b
object_c = c
array_a = c
array_b = c
array_c = c也就是说三个数组全都指向同一个关联对象，为了证实三个数组的内存地址是否一致，直接打印地址 修改get函数
get{
print("\(UnsafeRawPointer(self))")
if let rs = objc_getAssociatedObject(self, &objc_associate_ket_array) as! String?{
return rs
}else{
return "没有关联对象"
}
}得到输出
0x02504cb0
array_a = c
0x02504cb0
array_b = c
0x02504cb0
array_c = c居然真的一样！！
非空数组
内含OC对象
给数组加上object_a对象
array_a.append(object_a)
array_b.append(object_b)
array_c.append(object_c)得到的结果
object_a = a
object_b = b
object_c = c
0x7af37274
array_a = a
0x7c241854
array_b = b
0x7c241884
array_c = c完全正常，和预想的一致
内含Swift对象
将数组改成
var array_a:[Any] = []
var array_b:[Any] = []
var array_c:[Any] = []其余代码不变 输出结果变为
0x7a968424
array_a = 没有关联对象
0x7a874964
array_b = 没有关联对象
0x7a874994
array_c = 没有关联对象关联对象失效了！ 将Any换为String等Swift对象类型，依旧一样
查看内存地址
var fg_address:String{
get{
return "\(UnsafeRawPointer(self))"
}
}修改代码如下
let object_a = NSObject()
let object_b = NSObject()
let object_c = NSObject()
var array_a:[Any] = []
var array_b:[Any] = []
var array_c:[Any] = []
var mix_array:[[Any]] = []
override func viewDidLoad() {
super.viewDidLoad()
object_a.fg_tag = "a"
object_b.fg_tag = "b"
object_c.fg_tag = "c"
array_a.append(object_a)
array_b.append(object_b)
array_c.append(object_c)
array_a.fg_identify = "a"
array_b.fg_identify = "b"
array_c.fg_identify = "c"
mix_array.append(array_a)
mix_array.append(array_b)
mix_array.append(array_c)
mix_array.fg_identify = "mix"
// Do any additional setup after loading the view, typically from a nib.
}
override func viewDidAppear(_ animated: Bool){
super.viewDidAppear(animated)
print("object_a = \(object_a.fg_tag)")
print("object_b = \(object_b.fg_tag)")
print("object_c = \(object_c.fg_tag)")
print("array_a = \(array_a.fg_identify) + \(array_a.fg_address)")
print("array_b = \(array_b.fg_identify) + \(array_b.fg_address)")
print("array_c = \(array_c.fg_identify) + \(array_c.fg_address)")
print("mix_array0 = \(mix_array[0].fg_identify) + \(mix_array[0].fg_address)")
print("mix_array1 = \(mix_array[1].fg_identify) + \(mix_array[1].fg_address)")
print("mix_array2 = \(mix_array[2].fg_identify) + \(mix_array[2].fg_address)")
}输出
array_a = 没有关联对象 + 0x7bf86cc4
array_b = 没有关联对象 + 0x7bf86a64
array_c = 没有关联对象 + 0x7bf86a94
mix_array0 = 没有关联对象 + 0x7bf86cc4
mix_array1 = 没有关联对象 + 0x7bf86a64
mix_array2 = 没有关联对象 + 0x7bf86a94当数组被放进另一个数组时，会发现内存地址是一样的。
如果把array_a的类型改成[NSObject]呢，神奇的事情出现了
var array_a:[NSObject] = []输出
array_a = a + 0x0000610000053e80
array_b = 没有关联对象 + 0x0000610000260da0
array_c = 没有关联对象 + 0x0000610000260de0
mix_array0 = 没有关联对象 + 0x00006080002664a0
mix_array1 = 没有关联对象 + 0x0000610000260da0
mix_array2 = 没有关联对象 + 0x0000610000260de0当a被放进另外一个数组的时候，内存地址变了！并且a本身也能拿到关联对象
var array_a:[NSObject] = []
var array_b:[NSObject] = []
var array_c:[NSObject] = []输出
object_a = a
object_b = b
object_c = c
array_a = a + 0x00006180000496e0
array_b = b + 0x0000618000049260
array_c = c + 0x0000618000048540
mix_array0 = 没有关联对象 + 0x000061800026c320
mix_array1 = 没有关联对象 + 0x000061800026c460
mix_array2 = 没有关联对象 + 0x000061800026c4a0输出！
object_a = a
object_b = b
object_c = c
array_a = a + 0x000061000005a8d0
array_b = b + 0x000061000005ae10
array_c = c + 0x000061000005ae40
mix_array0 = a + 0x000061000005a8d0
mix_array1 = b + 0x000061000005ae10
mix_array2 = c + 0x000061000005ae40如果给空数组设置关联对象呢？
测试代码：改变一下位置
array_a.fg_identify = "a"
array_b.fg_identify = "b"
array_c.fg_identify = "c"
array_a.append(object_a)
array_b.append(object_b)
array_c.append(object_c)输出
object_a = a
object_b = b
object_c = c
array_a = 没有关联对象 + 0x0000618000244610
array_b = 没有关联对象 + 0x00006180002441f0
array_c = 没有关联对象 + 0x00006180002444f0
mix_array0 = 没有关联对象 + 0x0000618000244610
mix_array1 = 没有关联对象 + 0x00006180002441f0
mix_array2 = 没有关联对象 + 0x00006180002444f0本文参与 腾讯云自媒体同步曝光计划，分享自作者个人站点/博客。
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