将文件保存在 swift 中的文档目录中 3?
Save file in document directory in swift 3?
我正在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
但是如您所见,我没有使用 filemanager
获取文档目录路径,因为 filemanager
只给出 URL 而不是字符串。
问题:
- 如何从文件管理器中获取字符串?
- 我的代码有可能崩溃吗?
请反过来想。
URL
是处理文件路径的推荐方法,因为它包含所有用于添加和删除路径组件和扩展的便捷方法——而不是 String
,Apple 已经从中删除了这些方法。
不鼓励您像 path = path + name
那样连接路径。它很容易出错,因为您要对所有斜杠路径分隔符负责。
此外,您不需要使用 FileManager
创建文件。 Data
有一种方法可以将数据写入磁盘。
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 = image.jpegData(compressionQuality: 0.5) {
try imageData.write(to: fileURL)
return true
}
} catch {
print(error)
}
return false
func copyandpaste() {
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 {
}
}
}
按照 vadian 给出的上述示例,您需要在文档目录中保存(数据)文件的唯一行是:
try imageData.write(to: fileURL)
获取文件路径是有趣的部分
ex: 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)
}
我使用以下方法创建 "Test.txt" 文件。希望对你有帮助。
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)")
}
我正在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
但是如您所见,我没有使用 filemanager
获取文档目录路径,因为 filemanager
只给出 URL 而不是字符串。
问题:
- 如何从文件管理器中获取字符串?
- 我的代码有可能崩溃吗?
请反过来想。
URL
是处理文件路径的推荐方法,因为它包含所有用于添加和删除路径组件和扩展的便捷方法——而不是 String
,Apple 已经从中删除了这些方法。
不鼓励您像 path = path + name
那样连接路径。它很容易出错,因为您要对所有斜杠路径分隔符负责。
此外,您不需要使用 FileManager
创建文件。 Data
有一种方法可以将数据写入磁盘。
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 = image.jpegData(compressionQuality: 0.5) {
try imageData.write(to: fileURL)
return true
}
} catch {
print(error)
}
return false
func copyandpaste() {
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 {
}
}
}
按照 vadian 给出的上述示例,您需要在文档目录中保存(数据)文件的唯一行是:
try imageData.write(to: fileURL)
获取文件路径是有趣的部分
ex: 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)
}
我使用以下方法创建 "Test.txt" 文件。希望对你有帮助。
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)")
}