Swift 3:无法将文件写入Document Directory

Question

我想下载文件并写入文档目录，但是当我在simulator上运行时，它会返回这样的错误：

错误域= nscocoaerrordomain code = 4"文件夹" logo.jpg"不存在。"

我写这样的代码，我怎么了？谢谢。

var absPath = "./image/logo.png"
var sourceUrl = "http://www.example.com/data/"
var documentUrl = fileManager.urls(for: .documentDirectory, in: .userDomainMask)[0] as URL                   
let strIdx = absPath.index(absPath.startIndex, offsetBy: 2)
if (absPath.hasPrefix("./"))
{
   absPath = absPath.substring(from: strIdx)
}
let sourceUrl = URL(string: self.sourceUrl.appending(absPath))
let fileData = try NSData(contentsOf: sourceUrl!, options: NSData.ReadingOptions())
let destPath = documentUrl.appendingPathComponent(absPath)
do {
  try fileData.write(toFile: destPath.path, options: .atomicWrite)
} catch {
  print(error)
}

Answer 1

absPath包含一个子目录。如果要直接将文件保存到Documents中，则必须剥离image子目录。

let destPath = documentUrl.appendingPathComponent(sourceUrl!.lastPathComponent)

否则，您必须在Documents中创建image目录。

---

注意：在Swift 3中，请勿使用NSData，强烈建议使用与URL相关的API

do {
    let fileData = try Data(contentsOf: sourceUrl!)  
    try fileData.write(to: sourceUrl!, options: .atomic)
...