Swift 3 load image from local directory - ios

Question

I'm new to iOS dev and cannot figure out how to load an image in an imageView from a local directory.
I use imagePickerController to pick an image, get its info, then use this information to display the image in the imageView.
Here is the code to pick the image and its info dictionary:
func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {
let image = info[UIImagePickerControllerOriginalImage] as! UIImage
let imageUrl = info[UIImagePickerControllerReferenceURL] as! NSURL
let imageName = imageUrl.lastPathComponent
let documentDirectory = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true).first!
let photoURL = NSURL(fileURLWithPath: documentDirectory)
let localPath = photoURL.appendingPathComponent(imageName!)!
imagesList.append(localPath)
picker.dismiss(animated: true, completion: nil)
}
Then, and here is where I'm looking for some help, I want to use either localPath or imageUrl to load the image in another imageView but cannot figure out how.
I tried
func changeImage(_ sender: Any) {
if imagesList.count > 0 {
let imageUrlPath = imagesList[indexList]
let urlString: String = imageUrlPath.absoluteString
imageView.image = UIImage(contentsOfFile: urlString)
indexList = (indexList + 1) % imagesList.count
}
}
But I cannot have something working.
Any idea how I can achieve that?
Thank you for your help.

Answer 1

You'll want to save a reference to PHAsset objects, not URL strings.
Start with defining your Array as:
var imagesList = [PHAsset]()
Then, in didFinishPickingMediaWithInfo:
func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {
dismiss(animated: true)
// get the selected image as a UIImage object
let image = info[UIImagePickerControllerOriginalImage] as! UIImage
imageView.image = image
// save a PHAsset reference in imagesList array for later use
if let imageUrl = info[UIImagePickerControllerReferenceURL] as? URL{
let assets = PHAsset.fetchAssets(withALAssetURLs: [imageUrl], options: nil)
if let p = assets.firstObject {
imagesList.append(p)
}
}
}
Next, add a couple "convenience" functions:
func getAssetFullsize(asset: PHAsset) -> UIImage {
let manager = PHImageManager.default()
let option = PHImageRequestOptions()
var img = UIImage()
option.isSynchronous = true
let w = asset.pixelWidth
let h = asset.pixelHeight
manager.requestImage(for: asset, targetSize: CGSize(width: w, height: h), contentMode: .aspectFit, options: option, resultHandler: {(result, info)->Void in
img = result!
})
return img
}
func getAssetThumbnail(asset: PHAsset) -> UIImage {
let manager = PHImageManager.default()
let option = PHImageRequestOptions()
var thumbnail = UIImage()
option.isSynchronous = true
let w = 100
let h = 100
manager.requestImage(for: asset, targetSize: CGSize(width: w, height: h), contentMode: .aspectFit, options: option, resultHandler: {(result, info)->Void in
thumbnail = result!
})
return thumbnail
}
and finally, when you want to get the actual image:
func changeImage(_ sender: Any) {
if imagesList.count > 0 {
// get the full-size image from PHAsset
imageView.image = getAssetFullsize(asset: imagesList[indexList])
// or, just get a thumbnail-sized image
//imageView.image = getAssetThumbnail(asset: imagesList[indexList])
indexList = (indexList + 1) % imagesList.count
}
}
Naturally, you'll want to add appropriate error-checking, your own sizing, naming, tracking, etc... but I think this is the direction you want to head.