Question

我使用以下代码将文件保存在swift 3的文档目录中：

fileManager = FileManager.default
// let documentDirectory = fileManager?.urls(for: .documentDirectory, in: .userDomainMask).first as String
var path = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)[0] as String
path = path + name

let image = #imageLiteral(resourceName: "Notifications")
let imageData = UIImageJPEGRepresentation(image, 0.5)
let bool = fileManager?.createFile(atPath: path, contents: imageData, attributes: nil)

print("bool is \(bool)")
return true

但正如您所看到的，我没有使用filemanager来获取文档目录路径，因为filemanager只提供URL而不是字符串。

问题：

如何从文件管理器中获取字符串？
我的代码中是否有崩溃的可能性？

Answer 1

请反思。

URL是处理文件路径的推荐方法，因为它包含用于追加和删除路径组件和扩展的所有便捷方法 - 而不是Apple已从中移除这些方法的String。

不鼓励你连接像path = path + name这样的路径。它容易出错，因为你负责所有斜杠路径分隔符。

此外，您不需要使用FileManager创建文件。 Data有一种将数据写入磁盘的方法。

let fileManager = FileManager.default
do {
    let documentDirectory = try fileManager.url(for: .documentDirectory, in: .userDomainMask, appropriateFor:nil, create:false)
    let fileURL = documentDirectory.appendingPathComponent(name)
    let image = #imageLiteral(resourceName: "Notifications")
    if let imageData = UIImageJPEGRepresentation(image, 0.5) {
        try imageData.write(to: fileURL)
        return true
    }
} catch {
    print(error)
}
return false

Answer 2

按照vadian给出的上述示例，在文档目录中保存（数据）文件所需的唯一行是：

尝试imageData.write（to：fileURL）

获取文件路径是有趣的部分

例如：创建文件路径

 func createNewDirPath( )->URL{ 

let dirPathNoScheme = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)[0] as String

    //add directory path file Scheme;  some operations fail w/out it
    let dirPath = "file://\(dirPathNoScheme)"
    //name your file, make sure you get the ext right .mp3/.wav/.m4a/.mov/.whatever
    let fileName = "thisIsYourFileName.mov"
    let pathArray = [dirPath, fileName]
    let path = URL(string: pathArray.joined(separator: "/"))

    //use a guard since the result is an optional
    guard let filePath = path else {
        //if it fails do this stuff:
        return URL(string: "choose how to handle error here")!
    }
    //if it works return the filePath
    return filePath
}

调用函数：

let shinnyNewURLpath = createNewDirPath( ) 


//write data to file using one line in do/catch operation
do {
   try yourDataObject?.write(to: shinnyNewURLpath)
    } 
catch {
       print("catch error",error.localizedDescription)
 }

Answer 3

我使用以下方法创建＆＃34; Test.txt＆＃34;文件。希望它可以帮到你。

func createFile() {
    let fileName = "Test"
    let DocumentDirURL = try! FileManager.default.url(for: .documentDirectory, in: .userDomainMask, appropriateFor: nil, create: true)
    let fileURL = DocumentDirURL.appendingPathComponent(fileName).appendingPathExtension("txt")
    print("File PAth: \(fileURL.path)")
}

Answer 4

func copyandpast（）{

    var path  = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true);
    let dbpath :NSString = path[0] as NSString;

    let strdbpath =  dbpath.strings(byAppendingPaths: ["mydb.db"])[0] ;
    print(strdbpath);
    let fmnager  =  FileManager.default;

    if !fmnager.fileExists(atPath: strdbpath) {

        let local  = Bundle.main.path(forResource: "mydb", ofType: "db");

        do
        {
            try fmnager.copyItem(atPath: local!, toPath: strdbpath)

        }catch{

        }



    }


}

将文件保存在swift 3的文档目录中？

4 个答案: