使用 phimagemanager 将图像保存到自定义相册？

Question

我正在制作一个使用 AVFoundation 拍照的应用程序，我想将它们保存到一个自定义相册中，然后我可以在我的应用程序中查询和显示。 （我宁愿不在一般照片胶卷中使用它们，除非用户需要）我真的找不到任何显示如何在 Swift 中执行此操作的内容……或者根本找不到。 有没有不同的方式我应该这样做？

我在 SO 上找到了这个例子，但对我来说没有意义，我无法让它工作。

    func savePhoto() {
    var albumFound : Bool = false
    var assetCollection: PHAssetCollection!
    var photosAsset: PHFetchResult!
    var assetThumbnailSize:CGSize!

    // Create the album if does not exist (in viewDidLoad)
    if let first_Obj:AnyObject = collection.firstObject{
        //found the album
        self.albumFound = true
        self.assetCollection = collection.firstObject as PHAssetCollection
    }else{
        //Album placeholder for the asset collection, used to reference collection in completion handler
        var albumPlaceholder:PHObjectPlaceholder!
        //create the folder
        NSLog("\nFolder \"%@\" does not exist\nCreating now...", albumName)
        PHPhotoLibrary.sharedPhotoLibrary().performChanges({
            let request = PHAssetCollectionChangeRequest.creationRequestForAssetCollectionWithTitle(albumName)
            albumPlaceholder = request.placeholderForCreatedAssetCollection
            },
            completionHandler: {(success:Bool, error:NSError!)in
                NSLog("Creation of folder -> %@", (success ? "Success":"Error!"))
                self.albumFound = (success ? true:false)
                if(success){
                    let collection = PHAssetCollection.fetchAssetCollectionsWithLocalIdentifiers([albumPlaceholder.localIdentifier], options: nil)
                    self.assetCollection = collection?.firstObject as PHAssetCollection
                }
        })
    }



    let bundle = NSBundle.mainBundle()
    let myFilePath = bundle.pathForResource("highlight1", ofType: "mov")
    let videoURL:NSURL = NSURL.fileURLWithPath(myFilePath!)!

    let priority = DISPATCH_QUEUE_PRIORITY_DEFAULT
    dispatch_async(dispatch_get_global_queue(priority, 0), {
        PHPhotoLibrary.sharedPhotoLibrary().performChanges({
            //let createAssetRequest = PHAssetChangeRequest.creationRequestForAssetFromImage
            let createAssetRequest = PHAssetChangeRequest.creationRequestForAssetFromVideoAtFileURL(videoURL)
            let assetPlaceholder = createAssetRequest.placeholderForCreatedAsset
            let albumChangeRequest = PHAssetCollectionChangeRequest(forAssetCollection: self.assetCollection, assets: self.photosAsset)
            albumChangeRequest.addAssets([assetPlaceholder])
            }, completionHandler: {(success, error)in
                dispatch_async(dispatch_get_main_queue(), {
                    NSLog("Adding Image to Library -> %@", (success ? "Sucess":"Error!"))
                    //picker.dismissViewControllerAnimated(true, completion: nil)
                })
        })

    })
}

任何帮助/解释都会很棒！

Answer 1

这就是我的做法：

在顶部：

import Photos

var image: UIImage!
var assetCollection: PHAssetCollection!
var albumFound : Bool = false
var photosAsset: PHFetchResult!
var assetThumbnailSize:CGSize!
var collection: PHAssetCollection!
var assetCollectionPlaceholder: PHObjectPlaceholder!

创建相册：

func createAlbum() {
    //Get PHFetch Options
    let fetchOptions = PHFetchOptions()
    fetchOptions.predicate = NSPredicate(format: "title = %@", "camcam")
    let collection : PHFetchResult = PHAssetCollection.fetchAssetCollectionsWithType(.Album, subtype: .Any, options: fetchOptions)
    //Check return value - If found, then get the first album out
    if let _: AnyObject = collection.firstObject {
        self.albumFound = true
        assetCollection = collection.firstObject as! PHAssetCollection
    } else {
        //If not found - Then create a new album
        PHPhotoLibrary.sharedPhotoLibrary().performChanges({
            let createAlbumRequest : PHAssetCollectionChangeRequest = PHAssetCollectionChangeRequest.creationRequestForAssetCollectionWithTitle("camcam")
            self.assetCollectionPlaceholder = createAlbumRequest.placeholderForCreatedAssetCollection
            }, completionHandler: { success, error in
                self.albumFound = success

                if (success) {
                    let collectionFetchResult = PHAssetCollection.fetchAssetCollectionsWithLocalIdentifiers([self.assetCollectionPlaceholder.localIdentifier], options: nil)
                    print(collectionFetchResult)
                    self.assetCollection = collectionFetchResult.firstObject as! PHAssetCollection
                }
        })
    }
}

保存照片时：

func saveImage(){
        PHPhotoLibrary.sharedPhotoLibrary().performChanges({
            let assetRequest = PHAssetChangeRequest.creationRequestForAssetFromImage(self.image)
            let assetPlaceholder = assetRequest.placeholderForCreatedAsset
            let albumChangeRequest = PHAssetCollectionChangeRequest(forAssetCollection: self.assetCollection, assets: self.photosAsset)
            albumChangeRequest!.addAssets([assetPlaceholder!])
            }, completionHandler: { success, error in
                print("added image to album")
                print(error)

                self.showImages()
        })
    }

显示该相册中的图像：

func showImages() {
        //This will fetch all the assets in the collection

        let assets : PHFetchResult = PHAsset.fetchAssetsInAssetCollection(assetCollection, options: nil)
        print(assets)

        let imageManager = PHCachingImageManager()
        //Enumerating objects to get a chached image - This is to save loading time
        assets.enumerateObjectsUsingBlock{(object: AnyObject!,
            count: Int,
            stop: UnsafeMutablePointer<ObjCBool>) in

            if object is PHAsset {
                let asset = object as! PHAsset
                print(asset)

                let imageSize = CGSize(width: asset.pixelWidth, height: asset.pixelHeight)

                let options = PHImageRequestOptions()
                options.deliveryMode = .FastFormat

                imageManager.requestImageForAsset(asset, targetSize: imageSize, contentMode: .AspectFill, options: options, resultHandler: {(image: UIImage?,
                    info: [NSObject : AnyObject]?) in
                    print(info)
                    print(image)
                })
            }
        }

Answer 2

在Objective-C中回答并清理了一下。

__block PHFetchResult *photosAsset;
__block PHAssetCollection *collection;
__block PHObjectPlaceholder *placeholder;

// Find the album
PHFetchOptions *fetchOptions = [[PHFetchOptions alloc] init];
fetchOptions.predicate = [NSPredicate predicateWithFormat:@"title = %@", @"YOUR_ALBUM_TITLE"];
collection = [PHAssetCollection fetchAssetCollectionsWithType:PHAssetCollectionTypeAlbum
                                                      subtype:PHAssetCollectionSubtypeAny
                                                      options:fetchOptions].firstObject;
// Create the album
if (!collection)
{
    [[PHPhotoLibrary sharedPhotoLibrary] performChanges:^{
        PHAssetCollectionChangeRequest *createAlbum = [PHAssetCollectionChangeRequest creationRequestForAssetCollectionWithTitle:@"YOUR_ALBUM_TITLE"];
        placeholder = [createAlbum placeholderForCreatedAssetCollection];
    } completionHandler:^(BOOL success, NSError *error) {
        if (success)
        {
            PHFetchResult *collectionFetchResult = [PHAssetCollection fetchAssetCollectionsWithLocalIdentifiers:@[placeholder.localIdentifier]
                                                                                                            options:nil];
            collection = collectionFetchResult.firstObject;
        }
    }];
}

// Save to the album
[[PHPhotoLibrary sharedPhotoLibrary] performChanges:^{
    PHAssetChangeRequest *assetRequest = [PHAssetChangeRequest creationRequestForAssetFromImage:[UIImage imageWithData:imageData]];
    placeholder = [assetRequest placeholderForCreatedAsset];
    photosAsset = [PHAsset fetchAssetsInAssetCollection:collection options:nil];
    PHAssetCollectionChangeRequest *albumChangeRequest = [PHAssetCollectionChangeRequest changeRequestForAssetCollection:collection
                                                                                                                  assets:photosAsset];
    [albumChangeRequest addAssets:@[placeholder]];
} completionHandler:^(BOOL success, NSError *error) {
    if (success)
    {
        NSString *UUID = [placeholder.localIdentifier substringToIndex:36];
        self.photo.assetURL = [NSString stringWithFormat:@"assets-library://asset/asset.PNG?id=%@&ext=JPG", UUID];
        [self savePhoto];
    }
    else
    {
        NSLog(@"%@", error);
    }
}];

UUID 末尾的部分是我在另一个 StackOverflow 线程上发现的，用于从 ALAsset 创建 AssetURL 属性的替换。

注意：有关更完整的答案，请参阅下面的克里斯评论。

Answer 3

我喜欢重用我编写的代码，所以我决定为 PHPhotoLibrary 创建一个扩展，可以像这样使用它：

PHPhotoLibrary.saveImage(photo, albumName: "Trip") { asset in
    guard let asset = asset else {
        assert(false, "Asset is nil")
        return
    }
    PHPhotoLibrary.loadThumbnailFromAsset(asset) { thumbnail in
        print(thumbnail)
    }
}

这是代码： https : //gist.github.com/ricardopereira/636ccd0a3c8a327c43d42e7cbca4d041

Answer 4

针对 Swift 2.1+ 和视频进行了更新，以防您尝试这样做并在此处结束。 与其他答案的细微差别进行比较（例如用于图像而不是视频）

var photosAsset: PHFetchResult!
var collection: PHAssetCollection!
var assetCollectionPlaceholder: PHObjectPlaceholder!

//Make sure we have custom album for this app if haven't already
let fetchOptions = PHFetchOptions()
fetchOptions.predicate = NSPredicate(format: "title = %@", "MY_APP_ALBUM_NAME")
self.collection = PHAssetCollection.fetchAssetCollectionsWithType(.Album, subtype: .Any, options: fetchOptions).firstObject as! PHAssetCollection

//if we don't have a special album for this app yet then make one
if self.collection == nil {
     PHPhotoLibrary.sharedPhotoLibrary().performChanges({
        let createAlbumRequest : PHAssetCollectionChangeRequest = PHAssetCollectionChangeRequest.creationRequestForAssetCollectionWithTitle("MY_APP_ALBUM_NAME")
        self.assetCollectionPlaceholder = createAlbumRequest.placeholderForCreatedAssetCollection
             }, completionHandler: { success, error in
                if success {
                    let collectionFetchResult = PHAssetCollection.fetchAssetCollectionsWithLocalIdentifiers([self.assetCollectionPlaceholder.localIdentifier], options: nil)
                    print(collectionFetchResult)
                    self.collection = collectionFetchResult.firstObject as! PHAssetCollection
                }
            })
 }

//save the video to Photos                     
PHPhotoLibrary.sharedPhotoLibrary().performChanges({
     let assetRequest = PHAssetChangeRequest.creationRequestForAssetFromVideoAtFileURL(self.VIDEO_URL_FOR_VIDEO_YOU_MADE!)
     let assetPlaceholder = assetRequest!.placeholderForCreatedAsset
     self.photosAsset = PHAsset.fetchAssetsInAssetCollection(self.collection, options: nil)
     let albumChangeRequest = PHAssetCollectionChangeRequest(forAssetCollection: self.collection, assets: self.photosAsset)
     albumChangeRequest!.addAssets([assetPlaceholder!])
         }, completionHandler: { success, error in
               if success {
                  print("added video to album")
               }else if error != nil{
                  print("handle error since couldn't save video")
               }
         }
 })

Answer 5

我改进了 @ricardopereira 和 @ColossalChris 代码。 在扩展中添加了视频，并在 PHAsset 之上添加了另一个扩展以消除编译错误。 适用于 Swift 2.1。

示例用法：

#import "Yourtargetname-Swift.h"//important!
NSURL *videoURL = [[NSURL alloc] initFileURLWithPath:PATH_TO_VIDEO];

[PHPhotoLibrary saveVideo:videoURL albumName:@"my album" completion:^(PHAsset * asset) {
    NSLog(@"success");
    NSLog(@"asset%lu",(unsigned long)asset.pixelWidth);
}];

导入两个 swift 文件： https : //github.com/kv2/PHPhotoLibrary-PhotoAsset.swift

只要您为目标导入 swift 标头，它就可以在 Objective-c 中使用（请参阅ViewController.m文件）。