我正在使用 Xcode 6.3
和 swift(我认为是 1.2 版)。我的应用程序从网络上的自定义服务器下载照片。然后我希望它将具有给定文件名的照片保存到通过照片框架创建的自定义相册中。我需要能够控制照片/文件名,因为我会跟踪我在数据库中下载了哪些照片,以后需要按名称查看它们。
我创建了一个自定义的 PhotoAlbum 类,我试图将与相册交互的所有逻辑包装在其中。下载照片后,我可以调用以下代码,它可以创建相册并保存照片,但正如您在 savePhoto()
方法中注意到的那样,我不知道在何处/如何在保存时使用 photoName 变量来命名照片。最后,我还需要知道如何在 loadPhoto()
方法中按名称检索照片。
感谢您给我的任何帮助/建议。
let myAlbum = PhotoAlbum("MyAlbum")
myAlbum.savePhoto(downloadedPhoto, 12)
class PhotoAlbum {
var albumName: String = ""
var albumExists: Bool = false
var assetCollection: PHAssetCollection!
var photosAsset: PHFetchResult!
init(albumName: String) {
self.albumName = albumName
self.initializeAlbum()
}
private func initializeAlbum() {
let fetchOptions = PHFetchOptions()
fetchOptions.predicate = NSPredicate(format: "title = %@", self.albumName)
let collection: PHFetchResult = PHAssetCollection.fetchAssetCollectionsWithType(.Album, subtype: .Any, options: fetchOptions)
if let firstObject: AnyObject = collection.firstObject {
self.albumExists = true
self.assetCollection = collection.firstObject as! PHAssetCollection
if let ac = self.assetCollection {
self.photosAsset = PHAsset.fetchAssetsInAssetCollection(self.assetCollection, options: nil)
}
println("\(self.albumName) album exists")
}
else {
var albumPlaceHolder: PHObjectPlaceholder!
PHPhotoLibrary.sharedPhotoLibrary().performChanges({
let request = PHAssetCollectionChangeRequest.creationRequestForAssetCollectionWithTitle(self.albumName)
albumPlaceHolder = request.placeholderForCreatedAssetCollection
}, completionHandler: { (success: Bool, error: NSError!) in
self.albumExists = success
if success {
let collection = PHAssetCollection.fetchAssetCollectionsWithLocalIdentifiers([albumPlaceHolder.localIdentifier], options: nil)
self.assetCollection = collection.firstObject as! PHAssetCollection
if let ac = self.assetCollection {
self.photosAsset = PHAsset.fetchAssetsInAssetCollection(self.assetCollection, options: nil)
}
println("\(self.albumName) album made")
}
else {
println("Failed to create \(self.albumName) Album!!!!!!")
}
})
}
}
func savePhoto(image: UIImage, photoID: Int) {
let photoName = String(photoID)+".jpg"
PHPhotoLibrary.sharedPhotoLibrary().performChanges({
let assetRequest = PHAssetChangeRequest.creationRequestForAssetFromImage(image)
let assetPlaceholder = assetRequest.placeholderForCreatedAsset
let albumChangeRequest = PHAssetCollectionChangeRequest(forAssetCollection: self.assetCollection, assets: self.photosAsset)
albumChangeRequest.addAssets([assetPlaceholder])
}, completionHandler: { (success: Bool, error: NSError!) in
print(success ? "image added" : "failed to add image")
})
}
func loadPhoto(photoID: Int64) -> UIImage {
let photoName = String(photoID)+".jpg"
return UIImage(named: "no_photo")!
}
func renameAlbum(newAlbumName: String) {
// need to create the new album and move all photos to that album then remove the old album
}
func reloadPhotos() {
if let ac = self.assetCollection {
self.photosAsset = PHAsset.fetchAssetsInAssetCollection(self.assetCollection, options: nil)
}
}
最佳答案
而不是“命名”文件,您需要记下正在创建的 Assets 的 localIdentifier
属性。 localIdentifier
是一个持久标识符(即,它将是跨重启/重新加载的 Assets 的一致 ID)。
我拼凑了一些基本代码,您可以使用这些代码在保存图像时获取 localIdentifier
,并通过 localIdentifier
检索图像。希望这能让您继续前进。
import UIKit
import Photos
class MRPhotosHelper {
var manager = PHImageManager.defaultManager()
func saveImageAsAsset(image: UIImage, completion: (localIdentifier:String?) -> Void) {
var imageIdentifier: String?
PHPhotoLibrary.sharedPhotoLibrary().performChanges({ () -> Void in
let changeRequest = PHAssetChangeRequest.creationRequestForAssetFromImage(image)
let placeHolder = changeRequest.placeholderForCreatedAsset
imageIdentifier = placeHolder.localIdentifier
}, completionHandler: { (success, error) -> Void in
if success {
completion(localIdentifier: imageIdentifier)
} else {
completion(localIdentifier: nil)
}
})
}
func retrieveImageWithIdentifer(localIdentifier:String, completion: (image:UIImage?) -> Void) {
let fetchOptions = PHFetchOptions()
fetchOptions.predicate = NSPredicate(format: "mediaType == %d", PHAssetMediaType.Image.rawValue)
let fetchResults = PHAsset.fetchAssetsWithLocalIdentifiers([localIdentifier], options: fetchOptions)
if fetchResults.count > 0 {
if let imageAsset = fetchResults.objectAtIndex(0) as? PHAsset {
let requestOptions = PHImageRequestOptions()
requestOptions.deliveryMode = .HighQualityFormat
manager.requestImageForAsset(imageAsset, targetSize: PHImageManagerMaximumSize, contentMode: .AspectFill, options: requestOptions, resultHandler: { (image, info) -> Void in
completion(image: image)
})
} else {
completion(image: nil)
}
} else {
completion(image: nil)
}
}
}
然后你可以做这样的事情:
// get a reference to our helper
let helper = MRPhotosHelper()
// a var to store the localIdentifier for the image we save
var identifier:String?
// save the image to library
if let imageToSave = UIImage(named: "SomeImageName"){
helper.saveImageAsAsset(imageToSave, completion: { (localIdentifier) -> Void in
identifier = localIdentifier
})
}
// other stuff
// retrieve image from library at later date
if let identifier = identifier {
helper.retrieveImageWithIdentifer(identifier, completion: { (image) -> Void in
let retrievedImage = image
})
}
在使用更新 UI 之前,您可能需要检查您是否回到了完成闭包中的主线程。
关于ios - 通过 iOS swift 照片框架保存时如何命名照片,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/29854165/