迅速。无法将文件保存到 DocumentDirectory。怎么了？

Question

这是我的代码：

let fileName = "someFileName"

func saveDataToFile(urlStr:String){
    let url = NSURL(string: urlStr)
    var data:NSData!
    let paths = NSSearchPathForDirectoriesInDomains(NSSearchPathDirectory.DocumentDirectory, NSSearchPathDomainMask.UserDomainMask, true)
    let directory = paths[0]
    let filePath = directory.stringByAppendingPathComponent(self.fileName)
    print(filePath)//prints /Users/.../Library/Developer/CoreSimulator/Devices/1013B940-6FAB-406B-96FD-1774C670A91E/data/Containers/Data/Application/2F7139D6-C137-48BF-96F6-7579821B17B7/Documents/fileName

    let fileManager = NSFileManager.defaultManager()

    data = NSData(contentsOfURL: url!)
    print(data) // prints a lot of data     
    if data != nil{
        fileManager.createFileAtPath(filePath, contents: data, attributes: nil)
    }

}

现在我想读取这些数据：

func readDataFromFile(){
    let paths = NSSearchPathForDirectoriesInDomains(NSSearchPathDirectory.DocumentDirectory, NSSearchPathDomainMask.UserDomainMask, true)
    let directory = paths[0]
    let filePath = directory.stringByAppendingPathComponent(self.fileName)
    print(filePath) // prints the same path
    let fileManager = NSFileManager.defaultManager()
    if fileManager.fileExistsAtPath(filePath){
            data = fileManager.contentsAtPath(filePath)
        }else{
            print("*****BAD*****") // always prints this which means that file wasn`t created
        }
}

第一个函数有什么问题？将文件保存到 DocumentDirectory 的正确方法是什么？

Answer 1

好的，在这种情况下，答案如下：

首先需要创建目录（也称为文件夹），然后才在该目录中创建文件。

添加到代码中：

let fullDirPath = directory.stringByAppendingPathComponent(folderName)
let filePath = fullDirPath.stringByAppendingPathComponent(fileName)

do{
    try fileManager.createDirectoryAtPath(fullDirPath, withIntermediateDirectories: false, attributes: nil)
}catch let error as NSError{
    print(error.localizedDescription)
}

正如我所说，在此之后您将创建文件：

fileManager.createFileAtPath(filePath, contents: data, attributes: nil)

感谢Eric.D

希望有人会发现这很有用。