Swift：首次运行应用程序时，如何将文件从应用程序包复制到“文档”文件夹

Question

There are all sorts of sample code & questions on SO dealing with how to programmatically copy files in Obj-C from the app bundle to the application's sandboxed Documents folder (eg here , here , and here ) when the application runs for the first time.

How do you do this in Swift?

Answer 1

You could use FileManager API:

Here's example with a function that copies all files with specified extension:

func copyFilesFromBundleToDocumentsFolderWith(fileExtension: String) {
    if let resPath = Bundle.main.resourcePath {
        do {
            let dirContents = try FileManager.default.contentsOfDirectory(atPath: resPath)
            let documentsURL = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first
            let filteredFiles = dirContents.filter{ $0.contains(fileExtension)}
            for fileName in filteredFiles {
                if let documentsURL = documentsURL {
                    let sourceURL = Bundle.main.bundleURL.appendingPathComponent(fileName)
                    let destURL = documentsURL.appendingPathComponent(fileName)
                    do { try FileManager.default.copyItem(at: sourceURL, to: destURL) } catch { }
                }
            }
        } catch { }
    }
}

Usage:

copyFilesFromBundleToDocumentsFolderWith(fileExtension: ".txt")

Answer 2

For Swift 4.2:

Assuming the file in your App Bundle is called Some File.txt

In ViewDidLoad , add:

let docName = "Some File"
let docExt = "txt"
copyFileToDocumentsFolder(nameForFile: docName, extForFile: docExt)

and then create a function as follows:

func copyFileToDocumentsFolder(nameForFile: String, extForFile: String) {

    let documentsURL = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first
    let destURL = documentsURL!.appendingPathComponent(nameForFile).appendingPathExtension(extForFile)
    guard let sourceURL = Bundle.main.url(forResource: nameForFile, withExtension: extForFile)
        else {
            print("Source File not found.")
            return
    }
        let fileManager = FileManager.default
        do {
            try fileManager.copyItem(at: sourceURL, to: destURL)
        } catch {
            print("Unable to copy file")
        }
}