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获取Photos.app中的图像数量?

alassetslibrary photos numbers ios

SimplyKiwi · 技术社区 · 13 年前

我知道使用ALAssetsLibrary可以获取Photos.app中的图像,但我如何获取Photos.app中的照片总数?

几乎我正在尝试检查照片的数量,因为我正在获取photos.app中的最后一张图片,其中包含以下问题的代码: Get last image from Photos.app?

因此,如果设备上有0个图像,它将不会执行上面链接中的代码。

不管怎样,我怎么才能得到这个?

谢谢

2 回复 | 直到 9 年前

Rob 10 年前

随着新的 Photos 框架,在iOS 8中引入,您可以使用 estimatedAssetCount 以下为:

NSUInteger __block estimatedCount = 0;

PHFetchResult <PHAssetCollection *> *collections = [PHAssetCollection fetchAssetCollectionsWithType:PHAssetCollectionTypeAlbum subtype:PHAssetCollectionSubtypeAny options:nil];
[collections enumerateObjectsUsingBlock:^(PHAssetCollection * _Nonnull collection, NSUInteger idx, BOOL * _Nonnull stop) {
    estimatedCount += collection.estimatedAssetCount;
}];

这不包括智能相册(根据我的经验,它们没有有效的“估计数量”),所以你也可以提取资产来获得实际数量:

NSUInteger __block count = 0;

// Get smart albums (e.g. "Camera Roll", "Recently Deleted", "Panoramas", "Screenshots", etc.

PHFetchResult <PHAssetCollection *> *collections = [PHAssetCollection fetchAssetCollectionsWithType:PHAssetCollectionTypeSmartAlbum subtype:PHAssetCollectionSubtypeAlbumRegular options:nil];
[collections enumerateObjectsUsingBlock:^(PHAssetCollection * _Nonnull collection, NSUInteger idx, BOOL * _Nonnull stop) {
    PHFetchResult <PHAsset *> *assets = [PHAsset fetchAssetsInAssetCollection:collection options:nil];
    count += assets.count;
}];

// Get the standard albums (e.g. those from iTunes, created by apps, etc.), too

collections = [PHAssetCollection fetchAssetCollectionsWithType:PHAssetCollectionTypeAlbum subtype:PHAssetCollectionSubtypeAny options:nil];
[collections enumerateObjectsUsingBlock:^(PHAssetCollection * _Nonnull collection, NSUInteger idx, BOOL * _Nonnull stop) {
    PHFetchResult <PHAsset *> *assets = [PHAsset fetchAssetsInAssetCollection:collection options:nil];
    count += assets.count;
}];

顺便说一句,如果你还没有申请图书馆的授权,你应该这样做,例如:

[PHPhotoLibrary requestAuthorization:^(PHAuthorizationStatus status) {
    if (status == PHAuthorizationStatusAuthorized) {
        // insert your image counting logic here
    }
}];

与旧的 AssetsLibrary 框架,您可以 enumerateGroupsWithTypes 以下为:

NSUInteger __block count = 0;

[library enumerateGroupsWithTypes:ALAssetsGroupAll usingBlock:^(ALAssetsGroup *group, BOOL *stop) {
    if (!group) {
        // asynchronous counting is done; examine `count` here
    } else {
        count += group.numberOfAssets;
    }
} failureBlock:^(NSError *err) {
    NSLog(@"err=%@", err);
}];

// but don't use `count` here, as the above runs asynchronously

Akshit Zaveri 12 年前

使用 enumerateAssetsUsingBlock .每次结果不为零时,将其添加到数组中(我将调用它 self.arrayOfAssets )。然后,当您得到一个nil结果(枚举的终点)时 self.arrayOfAssets.count 。

编辑 :好的,这是另一个问题的代码,有几个改动。使用 enumerateAssetsUsingBlock: instead of enumerateAssetsAtIndexes:

给自己一个可变数组,并将每个图像放入其中。

然后,当asset为nil表示枚举已完成时,对数组进行计数。

    ALAssetsLibrary *library = [[ALAssetsLibrary alloc] init]; 

    self.allPhotos = [[NSMutableArray alloc] init];


    // Enumerate just the photos and videos group by using ALAssetsGroupSavedPhotos.
    [library enumerateGroupsWithTypes:ALAssetsGroupSavedPhotos                                                                   usingBlock:^(ALAssetsGroup *group, BOOL *stop) {

    // Within the group enumeration block, filter to enumerate just photos.
    [group setAssetsFilter:[ALAssetsFilter allPhotos]];

    [group enumerateAssetsUsingBlock:^(ALAsset *alAsset, NSUInteger index, BOOL *innerStop) {

    // The end of the enumeration is signaled by asset == nil.
    if (alAsset) {
         ALAssetRepresentation *representation = [alAsset defaultRepresentation];
         UIImage *latestPhoto = [UIImage imageWithCGImage:[representation fullScreenImage]];
        [self.allPhotos addObject:latestPhoto];
    if (!asset){
            NSLog:(@"photos count:%d", self.allPhotos.count);
            }
         }
    }];
 }
 failureBlock: ^(NSError *error) {
    // Typically you should handle an error more gracefully than this.
    NSLog(@"No groups");
  }];