如何在Swift 3中創建自定義相冊iOS 10

Question

這聽起來可能是重複的，但在搜索之後，我仍然沒有得到Swift 3的預期答案。 在我嘗試添加資產時使用addAssets()創建資產佔位符方法Xcode建議我將cast assetPlacehoder轉換爲FastEnumeration類型。當我這樣做的時候，它會導致一個異常。有人可以幫我嗎？

Answer 1

使用此課程並在需要時和在將圖像添加到相冊之前徵求權限。

class CustomPhotoAlbum: NSObject { 

     static let albumName = "YourAlbumName" 
     static let sharedInstance = CustomPhotoAlbum() 

     var assetCollection: PHAssetCollection! 

     override init() { 
      super.init() 

      if let assetCollection = fetchAssetCollectionForAlbum() { 
       self.assetCollection = assetCollection 
       return 
      } 
     } 

     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 \(String(describing: 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 , completion : @escaping() ->()) { 
      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!] 

       if self.assetCollection.estimatedAssetCount == 0 
       { 
        albumChangeRequest!.addAssets(enumeration) 
       } 
       else { 
        albumChangeRequest!.insertAssets(enumeration, at: [0]) 
       } 

      }, completionHandler: { status , errror in 
       completion() 
      }) 
     } 
} 

調用此方法要保存圖像。

CustomPhotoAlbum.sharedInstance.save(image: YourImage, completion: { 

         DispatchQueue.main.async(execute: { 
          //"Any UI update should be in main thread." 
         }) 
        })