ios - 仅从资产集合类型 PHAssetCollectionTypeSmartAlbum 中获取 PHAssetMediaTypeImage 类型的照片

Question

我正在使用 Photos 框架来获取 iOS8 中的专辑列表。我可以使用

PHFetchResult *smartAlbums = [PHAssetCollection fetchAssetCollectionsWithType:PHAssetCollectionTypeSmartAlbum subtype:PHAssetCollectionSubtypeAlbumRegular options:nil];

这给了我所有智能专辑的列表，包括视频。如何从此列表中过滤掉视频。我只需要图像。

帮助将不胜感激。谢谢。

Answer 1

您应该设置获取选项，它有一个属性predicate，可用于过滤视频。下面是一个这样做的例子。

PHFetchResult *smartAlbums = [PHAssetCollection fetchAssetCollectionsWithType:PHAssetCollectionTypeSmartAlbum subtype:PHAssetCollectionSubtypeAlbumRegular options:nil];

//set up fetch options, mediaType is image.
PHFetchOptions *options = [[PHFetchOptions alloc] init];
options.sortDescriptors = @[[NSSortDescriptor sortDescriptorWithKey:@"creationDate" ascending:NO]];
options.predicate = [NSPredicate predicateWithFormat:@"mediaType = %d",PHAssetMediaTypeImage];

for (NSInteger i =0; i < smartAlbums.count; i++) {
    PHAssetCollection *assetCollection = smartAlbums[i];
    PHFetchResult *assetsFetchResult = [PHAsset fetchAssetsInAssetCollection:assetCollection options:options];

    NSLog(@"sub album title is %@, count is %ld", assetCollection.localizedTitle, assetsFetchResult.count);
    if (assetsFetchResult.count > 0) {
        for (PHAsset *asset in assetsFetchResult) {
            //you have got your image type asset.
        }
    }
}

Answer 2

在 swift 中做同样的事情：

let fetchOptions = PHFetchOptions()
fetchOptions.predicate = NSPredicate(format: "mediaType = %d", PHAssetMediaType.Image.rawValue)