如何将图像保存到自定义相册？
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我有一个全新的ios应用程序，该应用程序可以生成图像，并让用户将其保存到Camera SavedPhotosAlbum中。但是，我想做Snapchat和Frontback之类的事情，并将这些图像也保存到自定义命名的相册中。
所以这是我现在的代码：
let imageToSave = self.currentPreviewImage
let softwareContext = CIContext(options:[kCIContextUseSoftwareRenderer: true])
let cgimg = softwareContext.createCGImage(imageToSave, fromRect:imageToSave.extent())
ALAssetsLibrary().writeImageToSavedPhotosAlbum(cgimg, metadata:imageToSave.properties(), completionBlock:nil)
[我已经看到了一些在Objective-C中进行此操作的示例，但是没有什么可以翻译成Swift的，而且我已经检查了writeImageToSavedPhotosAlbum方法签名，但它们似乎都不允许保存到自定义相册中。
答案
我想出了这个单例课程来处理它：
import Photos
class CustomPhotoAlbum {
static let albumName = "Flashpod"
static let sharedInstance = CustomPhotoAlbum()
var assetCollection: PHAssetCollection!
init() {
func fetchAssetCollectionForAlbum() -> PHAssetCollection! {
let fetchOptions = PHFetchOptions()
fetchOptions.predicate = NSPredicate(format: "title = %@", CustomPhotoAlbum.albumName)
let collection = PHAssetCollection.fetchAssetCollectionsWithType(.Album, subtype: .Any, options: fetchOptions)
if let firstObject: AnyObject = collection.firstObject {
return collection.firstObject as! PHAssetCollection
}
return nil
}
if let assetCollection = fetchAssetCollectionForAlbum() {
self.assetCollection = assetCollection
return
}
phphotoLibrary.sharedPhotoLibrary().performChanges({
PHAssetCollectionChangeRequest.creationRequestForAssetCollectionWithTitle(CustomPhotoAlbum.albumName)
}) { success, _ in
if success {
self.assetCollection = fetchAssetCollectionForAlbum()
}
}
}
func saveImage(image: UIImage) {
if assetCollection == nil {
return // If there was an error upstream, skip the save.
}
PHPhotoLibrary.sharedPhotoLibrary().performChanges({
let assetChangeRequest = PHAssetChangeRequest.creationRequestForAssetFromImage(image)
let assetPlaceholder = assetChangeRequest.placeholderForCreatedAsset
let albumChangeRequest = PHAssetCollectionChangeRequest(forAssetCollection: self.assetCollection)
albumChangeRequest.addAssets([assetPlaceholder])
}, completionHandler: nil)
}
}
第一次实例化该类时，如果自定义相册尚不存在，则会创建该相册。您可以像这样保存图像：
CustomPhotoAlbum.sharedInstance.saveImage(image)
注意：CustomPhotoAlbum类假定该应用程序已经具有访问照片库的权限。处理权限不在此问题/答案的范围之内。因此，请确保PHPhotoLibrary.authorizationStatus（）==。使用前进行授权。并在必要时请求授权。
另一答案
即使修复后，我的PhotoAlbum仍然无法用于第一张图像，如果我想一次保存多个图像，我最终会得到多个空相册。因此，我升级了班级，只在创建专辑后保存表情符号。
另一答案
Swift 4和5
另一答案
最新的Swift 3.0语法。 ：）
import Foundation
import Photos
class CustomPhotoAlbum: NSObject {
static let albumName = "Album Name"
static let sharedInstance = CustomPhotoAlbum()
var assetCollection: PHAssetCollection!
override init() {
super.init()
if let assetCollection = fetchAssetCollectionForAlbum() {
self.assetCollection = assetCollection
return
}
if PHPhotoLibrary.authorizationStatus() != PHAuthorizationStatus.authorized {
PHPhotoLibrary.requestAuthorization({ (status: PHAuthorizationStatus) -> Void in
()
})
}
if PHPhotoLibrary.authorizationStatus() == PHAuthorizationStatus.authorized {
self.createAlbum()
} else {
PHPhotoLibrary.requestAuthorization(requestAuthorizationHandler)
}
}
func requestAuthorizationHandler(status: PHAuthorizationStatus) {
if PHPhotoLibrary.authorizationStatus() == PHAuthorizationStatus.authorized {
// ideally this ensures the creation of the photo album even if authorization wasn't prompted till after init was done
print("trying again to create the album")
self.createAlbum()
} else {
print("should really prompt the user to let them know it's failed")
}
}
func createAlbum() {
PHPhotoLibrary.shared().performChanges({
PHAssetCollectionChangeRequest.creationRequestForAssetCollection(withTitle: CustomPhotoAlbum.albumName) // create an asset collection with the album name
}) { success, error in
if success {
self.assetCollection = self.fetchAssetCollectionForAlbum()
} else {
print("error (error)")
}
}
}
func fetchAssetCollectionForAlbum() -> PHAssetCollection? {
let fetchOptions = PHFetchOptions()
fetchOptions.predicate = NSPredicate(format: "title = %@", CustomPhotoAlbum.albumName)
let collection = PHAssetCollection.fetchAssetCollections(with: .album, subtype: .any, options: fetchOptions)
if let _: AnyObject = collection.firstObject {
return collection.firstObject
}
return nil
}
func save(image: UIImage) {
if assetCollection == nil {
return // if there was an error upstream, skip the save
}
PHPhotoLibrary.shared().performChanges({
let assetChangeRequest = PHAssetChangeRequest.creationRequestForAsset(from: image)
let assetPlaceHolder = assetChangeRequest.placeholderForCreatedAsset
let albumChangeRequest = PHAssetCollectionChangeRequest(for: self.assetCollection)
let enumeration: NSArray = [assetPlaceHolder!]
albumChangeRequest!.addAssets(enumeration)
}, completionHandler: nil)
}
}
另一答案
这是一个更新的版本，可在Swift 2.1中使用，避免了第一次创建时未创建相册且未保存图像的错误（当首次请求/授予写照片库的授权时。）]]
class CustomPhotoAlbum: NSObject {
static let albumName = "Name of Custom Album"
static let sharedInstance = CustomPhotoAlbum()
var assetCollection: PHAssetCollection!
override init() {
super.init()
if let assetCollection = fetchAssetCollectionForAlbum() {
self.assetCollection = assetCollection
return
}
if PHPhotoLibrary.authorizationStatus() != PHAuthorizationStatus.Authorized {
PHPhotoLibrary.requestAuthorization({ (status: PHAuthorizationStatus) -> Void in
status
})
}
if PHPhotoLibrary.authorizationStatus() == PHAuthorizationStatus.Authorized {
self.createAlbum()
} else {
PHPhotoLibrary.requestAuthorization(requestAuthorizationHandler)
}
}
func requestAuthorizationHandler(status: PHAuthorizationStatus) {
if PHPhotoLibrary.authorizationStatus() == PHAuthorizationStatus.Authorized {
// ideally this ensures the creation of the photo album even if authorization wasn't prompted till after init was done
print("trying again to create the album")
self.createAlbum()
} else {
print("should really prompt the user to let them know it's failed")
}
}
func createAlbum() {
PHPhotoLibrary.sharedPhotoLibrary().performChanges({
PHAssetCollectionChangeRequest.creationRequestForAssetCollectionWithTitle(CustomPhotoAlbum.albumName) // create an asset collection with the album name
}) { success, error in
if success {
self.assetCollection = self.fetchAssetCollectionForAlbum()
} else {
print("error (error)")
}
}
}
func fetchAssetCollectionForAlbum() -> PHAssetCollection! {
let fetchOptions = PHFetchOptions()
fetchOptions.predicate = NSPredicate(format: "title = %@", CustomPhotoAlbum.albumName)
let collection = PHAssetCollection.fetchAssetCollectionsWithType(.Album, subtype: .Any, options: fetchOptions)
if let _: AnyObject = collection.firstObject {
return collection.firstObject as! PHAssetCollection
}
return nil
}
func saveImage(image: UIImage, metadata: NSDictionary) {
if assetCollection == nil {
return // if there was an error upstream, skip the save
}
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