发行存储/中迅速恢复的全局字符串数组 [英] Issue storing/restoring a global string array in swift

问题描述

我通过一门课程的工作学习迅速。作为一个特定的项目方法的一部分，我创建一个名为全球字符串数组任务。

I am working through a course to learn swift. As part of a particular projects approach, I create a global string array called "tasks".

import UIKit

var tasks = [String]()

我遇到过的项目已要求，但现在我想要做的是使该阵列的应用程序的开口/倒闭之间永久的。迄今在使用过程中所描述的方法是使用

I have met the requirements for the project already, but now what I want to do is make that array permanent between app openings/closings. The method described in the course thus far is to use

override func viewDidLoad() {
    NSUserDefaults.standardUserDefaults().setObject(tasks, forKey: "array")
}

这应该将数组保存。问题出现时，我回想一下数组。

This should save the array. The problem comes in when I try to recall the array.

我已经试过这两种方法里面viewDidLoad中（）：

I've tried both of these methods inside viewDidLoad():

tasks = NSUserDefaults.standardUserDefaults().objectForKey("array")! as! NSArray

和

let returnedArray = NSUserDefaults.standardUserDefaults().objectForKey("array")! as! NSArray
        for i in returnedArray{
            tasks.append(returnedArray[i])
}

第一次给出了错误的NSArray是不可转换为[字符串]';'！为你的意思使用给力垂头丧气？

The first gives the error "NSArray is not convertible to '[String]'; did you mean to use 'as!' to force downcast?"

第二个给出了错误无法转换类型的值元素（又名AnyObject'）预期参数类型'诠释'。

The second gives the error "Cannot convert value of type 'Element' (aka 'AnyObject') to expected argument type 'Int'.

任何人都可以提供关于正在发生的事情一些指导？我仍然是一个相对的新手（仅在服用过程约2周）和大量的文件过于密集，我听不懂呢。

Can anyone provide some guidance on what is going on? I am still a relative newbie (only been taking the course for about 2 weeks) and a lot of the documentation is too dense for me to understand yet.

推荐答案

更改第一个

// tasks = NSUserDefaults.standardUserDefaults().objectForKey("array")! as! NSArray
tasks = defaults.objectForKey("array") as? [String] ?? [String]()

参考：的https://www.hackingwithswift.com/read/12/2/reading-and-writing-basics-nsuserdefaults

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