如何将代码目标 c 转换为 Swift 以保存图像？

Question

我在其他帖子中看到过这段代码，用于保存图片：

  // Create path.
 NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,      NSUserDomainMask, YES);
 NSString *filePath = [[paths objectAtIndex:0] stringByAppendingPathComponent:@"Image.png"];

// Save image.
[UIImagePNGRepresentation(image) writeToFile:filePath atomically:YES];

我正在尝试转换为 swift 以使用 avfoundatioin 保存照片，但我不知道在此处输入 NSDocumentDirectory 和 NSUserDomainMask 这个怎么转换？

谢谢！！

Answer 1

如下：

let nsDocumentDirectory = NSSearchPathDirectory.DocumentDirectory
let nsUserDomainMask = NSSearchPathDomainMask.UserDomainMask
if let paths = NSSearchPathForDirectoriesInDomains(nsDocumentDirectory, nsUserDomainMask, true) {
    if paths.count > 0 {
        if let dirPath = paths[0] as? String {
            let readPath = dirPath.stringByAppendingPathComponent("Image.png")
            let image = UIImage(named: readPath)
            let writePath = dirPath.stringByAppendingPathComponent("Image2.png") 
            UIImagePNGRepresentation(image).writeToFile(writePath, atomically: true)
        }
    }
}

“paths”是一个AnyObject[]，所以你必须检查它的元素是否可以转换为String。

当然，您实际上不会使用“NSDocumentDirectory”作为名称，我只是为了清楚起见。

Xcode 7.2 更新

NSSearchPathForDirectoriesInDomains 现在返回[String] 而不是[AnyObject]? 所以使用

let nsDocumentDirectory = NSSearchPathDirectory.DocumentDirectory
let nsUserDomainMask = NSSearchPathDomainMask.UserDomainMask
let paths = NSSearchPathForDirectoriesInDomains(nsDocumentDirectory, nsUserDomainMask, true)
if let dirPath = paths.first {
    // ...
}

.stringByAppendingPathComponent 也被弃用的事实在this answer 中得到处理...

Answer 2

这是我使用的：

    let fileManager = NSFileManager.defaultManager()
    let nsDocumentDirectory = NSSearchPathDirectory.DocumentDirectory
    let nsUserDomainMask = NSSearchPathDomainMask.UserDomainMask
    let documentsURL = fileManager.URLsForDirectory(nsDocumentDirectory, inDomains: nsUserDomainMask).last

Answer 3

这只是对 Swift 3

的 @पवन 答案的修改

import Foundation
import UIKit
import ImageIO
import MobileCoreServices

extension UIImage
{
    func write(at path:String) -> Bool
    {
        let result = CGImageWriteToFile(image: self.cgImage!, filePath: path)
        return result
    }

    private func CGImageWriteToFile(image:CGImage, filePath:String) -> Bool
    {
        let imageURL:CFURL = NSURL(fileURLWithPath: filePath)
        var destination:CGImageDestination? = nil

        let ext = (filePath as NSString).pathExtension.lowercased()
        if ext == "jpg" || ext == "jpeg"
        {
            destination = CGImageDestinationCreateWithURL(imageURL, kUTTypeJPEG, 1, nil)
        }
        else if ext == "png" || ext == "pngf"
        {
            destination = CGImageDestinationCreateWithURL(imageURL, kUTTypePNG, 1, nil)
        }
        else if ext == "tiff" || ext == "tif"
        {
            destination = CGImageDestinationCreateWithURL(imageURL, kUTTypeTIFF, 1, nil)
        }
        else  if ext == "bmpf" || ext == "bmp"
        {
            destination = CGImageDestinationCreateWithURL(imageURL, kUTTypeBMP, 1, nil)
        }


        guard destination != nil else {
            fatalError("Did not find any matching path extension to store the image")
        }

        CGImageDestinationAddImage(destination!, image, nil)

        if CGImageDestinationFinalize(destination!)
        {
            return true
        }
        return false
    }
}

及用法

let pickedImage = UIImage()
let path = (NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true).first! as NSString).appendingPathComponent("image.tif")
if pickedImage.write(at: path) == false
{
    print("failed to write file to disk!")
}

Answer 4

使用此类别可以将任何图像保存在文档目录中

import Foundation
import UIKit
import ImageIO
import MobileCoreServices

extension UIImage {
    func writeAtPath(path:String) -> Bool {

        let result = CGImageWriteToFile(self.CGImage!, filePath: path)
        return result
    }

    private func CGImageWriteToFile(image:CGImageRef, filePath:String) -> Bool {
        let imageURL:CFURLRef = NSURL(fileURLWithPath: filePath)
        var destination:CGImageDestinationRef? = nil

        let ext = (filePath as NSString).pathExtension.uppercaseString

        if ext == "JPG" || ext == "JPEG" {
            destination = CGImageDestinationCreateWithURL(imageURL, kUTTypeJPEG, 1, nil)
        } else if ext == "PNG" || ext == "PNGF" {
            destination = CGImageDestinationCreateWithURL(imageURL, kUTTypePNG, 1, nil)
        } else if ext == "TIFF" || ext == "TIF" {
            destination = CGImageDestinationCreateWithURL(imageURL, kUTTypeTIFF, 1, nil)
        } else if ext == "GIFF" || ext == "GIF" {
            destination = CGImageDestinationCreateWithURL(imageURL, kUTTypeGIF, 1, nil)
        } else if ext == "PICT" || ext == "PIC" || ext == "PCT" || ext == "X-PICT" || ext == "X-MACPICT" {
            destination = CGImageDestinationCreateWithURL(imageURL, kUTTypePICT, 1, nil)
        } else if ext == "JP2" {
            destination = CGImageDestinationCreateWithURL(imageURL, kUTTypeJPEG2000, 1, nil)
        } else  if ext == "QTIF" || ext == "QIF" {
            destination = CGImageDestinationCreateWithURL(imageURL, kUTTypeQuickTimeImage, 1, nil)
        } else  if ext == "ICNS" {
            destination = CGImageDestinationCreateWithURL(imageURL, kUTTypeAppleICNS, 1, nil)
        } else  if ext == "BMPF" || ext == "BMP" {
            destination = CGImageDestinationCreateWithURL(imageURL, kUTTypeBMP, 1, nil)
        } else  if ext == "ICO" {
            destination = CGImageDestinationCreateWithURL(imageURL, kUTTypeICO, 1, nil)
        } else {
            fatalError("Did not find any matching path extension to store the image")
        }

        if (destination == nil) {
            fatalError("Did not find any matching path extension to store the image")
            return false
        } else {
            CGImageDestinationAddImage(destination!, image, nil)

            if CGImageDestinationFinalize(destination!) {
                return false
            }
            return true
        }
    }
}

//这是在你的应用程序中使用这个类别的方法。

func testImageWrite() -> Bool {

    let img = UIImage(named: "test")

    var path = NSSearchPathForDirectoriesInDomains(NSSearchPathDirectory.DocumentDirectory, NSSearchPathDomainMask.UserDomainMask, true)[0]
    path = (path as NSString).stringByAppendingPathComponent("Test.png")

    let result = img?.writeAtPath(path)

    return result!
}

Answer 5

对于 xCode 8.1、swift 3.0 你可以这样做：

let path = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true).first!

我认为这更简洁。