是否可以在 SwiftUI/Swift 中改变 class function 内部的数组？

Question

如果我在 class 中声明了一个数组，是否可以从该类的一个函数中改变该数组？ 我希望有一些等效的“变异”关键字可用于类：

class className: ObservableObject {
    @Published var arrayName: [arrayType] = []

    func mutateArray(address: String) {
        self.arrayName = []
        let geocoder = Geocoder(accessToken: 'accessTokenHere')
        geocoder.geocode(ForwardGeocodeOptions(query: address) { (placemarks, attribution, error) in 
        guard let placemarks = placemarks
        else {
            return
        }
        self.arrayName = [value1, value2, value3]
        //This only updates the array inside this closure/context. Is there any way to have the update persist after the function has ended?
    }
}

Answer 1

类不需要mutating的等价物，因为它是引用类型，不像结构是值类型，这就是它需要mutating函数的原因。 在你的 Xcode-playground 上试试这个代码：

import Foundation

class className {
    var arrayName: [String] = []

    func mutateArray() {
        arrayName = ["value1", "value2", "value3"]
    }
}
let object = className()
print(object.arrayName)
object.mutateArray()
print(object.arrayName)

Answer 2

应在主队列上更新已发布的属性，因此请执行以下操作

class ClassName: ObservableObject {
    @Published var arrayName: [arrayType] = []

    func mutateArray(address: String) {
        self.arrayName = []
        let geocoder = Geocoder(accessToken: 'accessTokenHere')
        geocoder.geocode(ForwardGeocodeOptions(query: address) { [weak self] (placemarks, attribution, error) in
            guard let placemarks = placemarks
                else {
                    return
            }
            DispatchQueue.main.async {     // << here !!
                self?.arrayName = [value1, value2, value3] // << weak for safety
            }
        }
    }
}