如何正确检测PHAsset的文件类型(GIF)

Question

我不知道为什么这么难.我正在尝试确定PHAsset的文件类型,具体来说,我想知道给定的资产是否代表GIF图像.

只需检查资产的文件名告诉我它是MP4:

[asset valueForKey:@"filename"] ==> "IMG_XXXX.MP4"

iOS保存到设备图像库时,是否会将GIF转换为视频？我也尝试获取图像的数据并查看它的dataUTI,但它只返回nilGIF(我也假设所有视频).我正在获取图像数据如下:

PHImageManager *manager = asset.imageManager ? asset.imageManager : [PHImageManager defaultManager];

dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{

    PHImageRequestOptions *o = [[PHImageRequestOptions alloc] init];
    o.networkAccessAllowed = YES;

    [manager requestImageDataForAsset:asset.asset options:o resultHandler:^(NSData * _Nullable imageData, NSString * _Nullable dataUTI, UIImageOrientation orientation, NSDictionary * _Nullable info) {

        dispatch_async(dispatch_get_main_queue(), ^{
            CIImage *ciImage = [CIImage imageWithData:imageData];
            if(completion) completion(imageData, dataUTI, orientation, info, ciImage.properties);
        });

    }];

});

从上面的调用返回的dataUTI是nil.

如果有人知道确定PHAsset文件类型的可靠方法(我特意寻找GIF,但能够确定任何类型的文件会很棒)请告诉我!

Answer 1

使用PHAssetResource.

    NSArray *resourceList = [PHAssetResource assetResourcesForAsset:asset];
    [resourceList enumerateObjectsUsingBlock:^(id  _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {
        PHAssetResource *resource = obj;
        if ([resource.uniformTypeIdentifier isEqualToString:@"com.compuserve.gif"]) {
           isGIFImage = YES;
        }
    }];

Answer 2

您还可以从PHContentEditingInput类中找到uniformTypeIdentifier.为了这; 使用PHAsset中的requestContentEditingInput函数

不要忘记为kUTTypeGif导入MobileCoreServices

示例Swift 3.1代码:

    let options = PHContentEditingInputRequestOptions()
    options.isNetworkAccessAllowed = true //for icloud backup assets

    let asset : PHAsset = .....  //sampleAsset
    asset.requestContentEditingInput(with: options) { (contentEditingInput, info) in
        if let uniformTypeIdentifier = contentEditingInput?.uniformTypeIdentifier {

            if uniformTypeIdentifier == (kUTTypeGIF as String) {
                debugPrint("This asset is a GIF")
            }

        }
    }

Answer 3

对于 Swift 3.0 及以上

import MobileCoreServices


var isGIFImage = false
if let identifier = asset.value(forKey: "uniformTypeIdentifier") as? String
{
  if identifier == kUTTypeGIF as String
  {
    isGIFImage = true
  }
}

Answer 4

首先，我不知道你所说的GIF图像是什么意思。
您指的是实时照片还是延时摄影？

但是，如果您想检查当前资源是Live Photo、Time-lapse，那么您可以这样检查

if(asset.mediaSubtypes == PHAssetMediaSubtypePhotoLive)
{
     // this is a Live Photo
}

if(asset.mediaSubtypes == PHAssetMediaSubtypeVideoTimelapse)
{
     // this is a Time-lapse
}

要确定 PHAsset 的通用文件类型，您可以检查

   asset.mediaType == PHAssetMediaTypeImage 
   asset.mediaType == PHAssetMediaTypeVideo
   asset.mediaType == PHAssetMediaTypeAudio