如何在 Swift 中从文件夹中获取 UIImage 数组？

Question

I have an ordinary Xcode project like this ...

notice there's a folder (it is an actual folder - not just a group) named "images". It contains 25 ".png" images.

All I want to do is make an array of UIimage with each of those images.

(Or even, an array of the image names or similar, that would be fine - then could load them UIImage(named: )

How do I get at that folder "images"?? What about a subfolder "images/cars"?

I tried something like this but it finds nothing...

override func viewDidLoad()
    {
    let imageArray = NSBundle.mainBundle().URLsForResourcesWithExtension(
          "png", subdirectory: "images")
    print("test...")
    for n:NSURL in imageArray!
        { print("found ..." ,n) }
    }

Answer 1

We we assume the images are in the app's resource bundle. If not you need to make sure that your images directory is listed in the "Copy Bundle Resources" in the "Build Phases" of the target.

EDIT This is only going copy the images into the app bundle, if you require the folder to be copied to the app bundle per the code below then please use the follow StackOverflow question to set it up correctly.

This gives us an array of URL's that we can then use with UIImage(data:) and NSData(contentsOfURL:) to create the image when needed.

Get the bundle's resource path and append the image directory then get the contents of the directory.

     if let path = NSBundle.mainBundle().resourcePath {

        let imagePath = path + "/images"
        let url = NSURL(fileURLWithPath: imagePath)
        let fileManager = NSFileManager.defaultManager()

        let properties = [NSURLLocalizedNameKey,
                          NSURLCreationDateKey, NSURLLocalizedTypeDescriptionKey]

        do {
            let imageURLs = try fileManager.contentsOfDirectoryAtURL(url, includingPropertiesForKeys: properties, options:NSDirectoryEnumerationOptions.SkipsHiddenFiles)

            print("image URLs: \(imageURLs)")
            // Create image from URL
            var myImage =  UIImage(data: NSData(contentsOfURL: imageURLs[0])!)

        } catch let error1 as NSError {
            print(error1.description)
        }
    }

Answer 2

Please try the following:

1. You have to register your images to "Copy Bundle Resources".

2. You have to add filter module in main Bundle. enter image description here

It is working well on my side. Maybe you can change filter from "jpg" format into "png" one.

I've tested on iOS 10.x later, Swift 3.0 and xcode 8.1 version.

Answer 3

I would advise against loading all of your images into an array at once. Images tend to be large and it's easy to run out of memory and crash.

Unless you absolutely have to have all the images in memory at once it's better to keep an array of paths or URLs and load the images one at a time as needed.

Assuming the folder full of images is in your app bundle, you can use the NSBundle method URLsForResourcesWithExtension:subdirectory: to get an array of NSURL s to all the files in your images subdirectory, either with a specific filetype, or ALL files (if you pass nil for the extension.)

Once you have an array of file urls you can map it to an array of paths if needed, and then map that to an array of images.

Answer 4

Swift 4

    if let path = Bundle.main.resourcePath {
        let imagePath = path + "/images"
        let url = NSURL(fileURLWithPath: imagePath)
        let fileManager = FileManager.default

        let properties = [URLResourceKey.localizedNameKey,
                          URLResourceKey.creationDateKey, 
                          URLResourceKey.localizedTypeDescriptionKey]

        do {
            let imageURLs = try fileManager.contentsOfDirectory(at: url as URL, includingPropertiesForKeys: properties, options:FileManager.DirectoryEnumerationOptions.skipsHiddenFiles)

            print("image URLs: \(imageURLs)")
            // Create image from URL
            let firstImageURL = imageURLs[0]
            let firstImageData = try Data(contentsOf: firstImageURL)
            let firstImage = UIImage(data: firstImageData)

            // Do something with first image

        } catch let error as NSError {
            print(error.description)
        }
    }

Answer 5

You can follow these steps to download them:

1. Create a new folder in finder and add all images (or folder, ... everything).

2. Change folder name + ".bundle" (for example: YourListImage -> YourListImage.bundle).

3. Add folder to project.

4. Add FileManager extension:

    extension FileManager { func getListFileNameInBundle(bundlePath: String) -> [String] { let fileManager = FileManager.default let bundleURL = Bundle.main.bundleURL let assetURL = bundleURL.appendingPathComponent(bundlePath) do { let contents = try fileManager.contentsOfDirectory(at: assetURL, includingPropertiesForKeys: [URLResourceKey.nameKey, URLResourceKey.isDirectoryKey], options: .skipsHiddenFiles) return contents.map{$0.lastPathComponent} } catch { return [] } } func getImageInBundle(bundlePath: String) -> UIImage? { let bundleURL = Bundle.main.bundleURL let assetURL = bundleURL.appendingPathComponent(bundlePath) return UIImage.init(contentsOfFile: assetURL.relativePath) } }

5. Use:

    let fm = FileManager.default let listImageName = fm.getListFileNameInBundle(bundlePath: "YourListImage.bundle") for imgName in listImageName { let image = fm.getImageInBundle(bundlePath: "YourListImage.bundle/\\(imgName)") }