ios-需要掌握的知识点

iOS FileManager 文件及文件夹处理

2020-03-05  本文已影响0人  A_rcher34

FileManager

1. 获取用户文档目录路径

let manager = FileManager.default
var documentsURL = manager.urls(for: .documentDirectory, in: .userDomainMask)[0]

2. 搜索

let contentsOfPath = try? manager.contentsOfDirectory(atPath: documentsURL.path)

print("contentsOfPath: \(contentsOfPath)")
let contentsOfURL = try? manager.contentsOfDirectory(at: url, includingPropertiesForKeys: nil, options: .skipsHiddenFiles)

print("contentsOfURL: \(contentsOfURL)")
let enumeratorAtPath = manager.enumerator(atPath: url.path)

print("enumeratorAtPath: \(enumeratorAtPath?.allObjects)")
let enumeratorAtURL = manager.enumerator(at: url, includingPropertiesForKeys: nil, options: .skipsHiddenFiles, errorHandler:nil)

print("enumeratorAtURL: \(enumeratorAtURL?.allObjects)")
let subPaths = manager.subpaths(atPath: url.path)

print("subPaths: \(subPaths)")

3. 判断文件或文件夹是否存在

let filePath:String = NSHomeDirectory() + "/Documents/test.txt"

let exist = manager.fileExists(atPath: filePath)

4. 创建文件夹

let myDirectory:String = NSHomeDirectory() + "/Documents/myFolder/Files"

// 方法1
try! manager.createDirectory(atPath: myDirectory, withIntermediateDirectories: true, attributes: nil)
// 方法2
let folder = baseUrl.appendingPathComponent(name, isDirectory: true)
let exist = manager.fileExists(atPath: folder!.path)
if !exist {
    try! manager.createDirectory(at: folder!, withIntermediateDirectories: true, attributes: nil)
}

5. 在文档目录下新建folder目录

let urlForDocument = manager.urls(for: .documentDirectory, in: .userDomainMask)

let url = urlForDocument[0] as NSURL

createFolder(name: "folder", baseUrl: url)

6. 将对象写入文件

可以通过write(to:)方法,可以创建文件并将对象写入,对象包括String,NSString,UIImage,NSArray,NSDictionary等。

let filePath:String = NSHomeDirectory() + "/Documents/test.txt"

let info = "Hello World!"

try! info.write(toFile: filePath, atomically: true, encoding: String.Encoding.utf8)
let filePath = NSHomeDirectory() + "/Documents/test.png"

let image = UIImage(named: "apple.png")

let data:Data = UIImagePNGRepresentation(image!)!

try? data.write(to: URL(fileURLWithPath: filePath))
let array = NSArray(objects: "aaa","bbb","ccc")

let filePath:String = NSHomeDirectory() + "/Documents/array.plist"

array.write(toFile: filePath, atomically: true)
let dictionary:NSDictionary = ["Gold": "1st Place", "Silver": "2nd Place"]

let filePath:String = NSHomeDirectory() + "/Documents/dictionary.plist"

dictionary.write(toFile: filePath, atomically: true)

7. 创建文件

func createFile(name:String, fileBaseUrl:URL){
    let manager = FileManager.default
    let file = fileBaseUrl.appendingPathComponent(name)
    print("文件: \(file)")

    let exist = manager.fileExists(atPath: file.path)
    if !exist {
        let data = Data(base64Encoded:"aGVsbG8gd29ybGQ=" ,options:.ignoreUnknownCharacters)
        let createSuccess = manager.createFile(atPath: file.path,contents:data,attributes:nil)
        print("文件创建结果: \(createSuccess)")
    }
}
let urlForDocument = manager.urls( for: .documentDirectory, in:.userDomainMask)

let url = urlForDocument[0]

createFile(name:"test.txt", fileBaseUrl: url)
// 或者:createFile(name: "folder/new.txt", fileBaseUrl: url)

8. 复制文件

let fileManager = FileManager.default

let homeDirectory = NSHomeDirectory()

let srcUrl = homeDirectory + "/Documents/test.txt"

let toUrl = homeDirectory + "/Documents/copyed.txt"

try! fileManager.copyItem(atPath: srcUrl, toPath: toUrl)
// 定位到用户文档目录
let manager = FileManager.default
let urlForDocument = manager.urls( for:.documentDirectory, in:.userDomainMask)
let url = urlForDocument[0]

// 将test.txt文件拷贝到文档目录根目录下的copyed.txt文件
let srcUrl = url.appendingPathComponent("test.txt")
let toUrl = url.appendingPathComponent("copyed.txt")
try! manager.copyItem(at: srcUrl, to: toUrl)

9. 移动文件

let fileManager = FileManager.default

let homeDirectory = NSHomeDirectory()

let srcUrl = homeDirectory + "/Documents/test.txt"

let toUrl = homeDirectory + "/Documents/moved/test.txt"

try! fileManager.moveItem(atPath: srcUrl, toPath: toUrl)
// 定位到用户文档目录
let manager = FileManager.default
let urlForDocument = manager.urls( for: .documentDirectory, in:.userDomainMask)
let url = urlForDocument[0]
        
let srcUrl = url.appendingPathComponent("test.txt")
let toUrl = url.appendingPathComponent("copyed.txt")

// 移动srcUrl中的文件(test.txt)到toUrl中(copyed.txt)
try! manager.moveItem(at: srcUrl, to: toUrl)

10. 删除文件

let fileManager = FileManager.default

let homeDirectory = NSHomeDirectory()

let srcUrl = homeDirectory + "/Documents/test.txt"

try! fileManager.removeItem(atPath: srcUrl)
// 定位到用户文档目录
let manager = FileManager.default
let urlForDocument = manager.urls(for: .documentDirectory, in:.userDomainMask)
let url = urlForDocument[0]
let toUrl = url.appendingPathComponent("copyed.txt")

// 删除文档根目录下的toUrl路径的文件(copyed.txt文件)
try! manager.removeItem(at: toUrl)

11. 删除目录下所有的文件

let fileManager = FileManager.default

let myDirectory = NSHomeDirectory() + "/Documents/Files"

let fileArray = fileManager.subpaths(atPath: myDirectory)

for fn in fileArray!{
    try! fileManager.removeItem(atPath: myDirectory + "/\(fn)")
}
let fileManager = FileManager.default

let myDirectory = NSHomeDirectory() + "/Documents/Files"

try! fileManager.removeItem(atPath: myDirectory)

try! fileManager.createDirectory(atPath: myDirectory, withIntermediateDirectories: true, attributes: nil)

12. 读取文件

let manager = FileManager.default

let urlsForDocDirectory = manager.urls(for: .documentDirectory, in:.userDomainMask)

let docPath = urlsForDocDirectory[0]

let file = docPath.appendingPathComponent("test.txt")

// 方法1

let readHandler = try! FileHandle(forReadingFrom:file)

let data = readHandler.readDataToEndOfFile()

let readString = String(data: data, encoding: String.Encoding.utf8)

print("文件内容: \(readString)")

// 方法2

let data2 = manager.contents(atPath: file.path)

let readString2 = String(data: data2!, encoding: String.Encoding.utf8)

print("文件内容: \(readString2)")

13. 在任意位置写入数据

let manager = FileManager.default

let urlsForDocDirectory = manager.urls(for:.documentDirectory, in:.userDomainMask)

let docPath = urlsForDocDirectory[0]

let file = docPath.appendingPathComponent("test.txt")

let string = "添加一些文字到文件末尾"

let appendedData = string.data(using: String.Encoding.utf8, allowLossyConversion: true)

let writeHandler = try? FileHandle(forWritingTo:file)

writeHandler!.seekToEndOfFile()

writeHandler!.write(appendedData!)

14. 文件权限判断

let manager = FileManager.default

let urlForDocument = manager.urls(for: .documentDirectory, in:.userDomainMask)

let docPath = urlForDocument[0]

let file = docPath.appendingPathComponent("test.txt")

let readable = manager.isReadableFile(atPath: file.path)

print("可读: \(readable)")

let writeable = manager.isWritableFile(atPath: file.path)

print("可写: \(writeable)")

let executable = manager.isExecutableFile(atPath: file.path)

print("可执行: \(executable)")

let deleteable = manager.isDeletableFile(atPath: file.path)

print("可删除: \(deleteable)")

15. 获取文件属性(创建时间,修改时间,文件大小,文件类型等信息)

let manager = FileManager.default

let urlForDocument = manager.urls(for: .documentDirectory, in:.userDomainMask)

let docPath = urlForDocument[0]

let file = docPath.appendingPathComponent("test.txt")

let attributes = try? manager.attributesOfItem(atPath: file.path) //结果为Dictionary类型

print("attributes: \(attributes!)")

// 从 attributes 中获取具体的属性:

print("创建时间:\(attributes![FileAttributeKey.creationDate]!)")

print("修改时间:\(attributes![FileAttributeKey.modificationDate]!)")

print("文件大小:\(attributes![FileAttributeKey.size]!)")

16. 文件/文件夹比较

let manager = FileManager.default

let urlForDocument = manager.urls(for: .documentDirectory, in:.userDomainMask)

let docPath = urlForDocument[0]

let contents = try! manager.contentsOfDirectory(atPath: docPath.path)

// 下面比较用户文档中前面两个文件是否内容相同(该方法也可以用来比较目录)

let count = contents.count

if count > 1 {

    let path1 = docPath.path + "/" + (contents[0] as String)

    let path2 = docPath.path + "/" + (contents[1] as String)

    let equal = manager.contentsEqual(atPath: path1,andPath:path2)

    print("path1:\(path1)")

    print("path2:\(path2)")

    print("比较结果: \(equal)")

}

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