iOS 8 PhotoKit。从iCloud照片共享相册中获取最大大小的图像

Question

如何从IС大声访问全尺寸图像？每次我试图得到这张照片，我得到的图像大小256x342。我也没看到进展。

代码：

    PHFetchResult *result = [PHAsset fetchAssetsWithLocalIdentifiers:@[assetIdentifier] options:nil];
    PHImageManager *manager = [PHImageManager defaultManager];
    [result enumerateObjectsUsingBlock:^(PHAsset *asset, NSUInteger idx, BOOL *stop) {

        PHImageRequestOptions *options = [[PHImageRequestOptions alloc] init];
        options.deliveryMode = PHImageRequestOptionsDeliveryModeHighQualityFormat;
        options.synchronous = YES;
        options.networkAccessAllowed = YES;
        options.progressHandler = ^(double progress, NSError *error, BOOL *stop, NSDictionary *info) {
            NSLog(@"%f", progress);
        };

        [manager requestImageForAsset:asset targetSize:PHImageManagerMaximumSize contentMode:PHImageContentModeDefault options:options resultHandler:^(UIImage *resultImage, NSDictionary *info)
         {
             UIImage *image = resultImage;
             NSLog(@"%@", NSStringFromCGSize(resultImage.size));
         }];
    }];

在我点击照片应用程序中的图片之前，这张图片的质量会很差。但只要我一点击图片，它就会下载到设备上，并且将是全尺寸的质量。

Answer 1

我认为以下应该获得完整的分辨率图像数据：

 [manager requestImageDataForAsset:asset 
                           options:options 
                     resultHandler:^(NSData *imageData, NSString *dataUTI, UIImageOrientation orientation, NSDictionary *info) 
             { 
                  UIImage *image = [UIImage imageWithData:imageData]; 

                  //...

             }];

整个照片框架(PhotoKit)包括在WWDC视频中：https://developer.apple.com/videos/wwdc/2014/#511

希望这能有所帮助。

编辑：

resultHandler可以被调用两次。我在30点左右链接到的视频中解释了这一点。可能是你只得到缩略图和完整的图像将与第二次调用。

Answer 2

我也有同样的问题。这要么是一个错误，要么是糟糕的文档。我已经能够通过指定所请求的2000x2000大小来解决这个问题。问题是，我确实得到了完整的图像，但有时它会被标记为退化，所以我一直在等待一个从未发生过的不同的图像。我就是这么做来解决这些问题的。

        self.selectedAsset = asset;

        self.collectionView.allowsSelection = NO;

        PHImageRequestOptions* options = [[[PHImageRequestOptions alloc] init] autorelease];
        options.synchronous = NO;
        options.version = PHImageRequestOptionsVersionCurrent;
        options.deliveryMode = PHImageRequestOptionsDeliveryModeOpportunistic;
        options.resizeMode = PHImageRequestOptionsResizeModeNone;
        options.networkAccessAllowed = YES;
        options.progressHandler =  ^(double progress,NSError *error,BOOL* stop, NSDictionary* dict) {
            NSLog(@"progress %lf",progress);  //never gets called
        };

        [self.delegate choosePhotoCollectionVCIsGettingPhoto:YES];  //show activity indicator
        __block BOOL isStillLookingForPhoto = YES;

        currentImageRequestId = [[PHImageManager defaultManager] requestImageForAsset:asset targetSize:CGSizeMake(2000, 2000) contentMode:PHImageContentModeAspectFill options:options resultHandler:^(UIImage *result, NSDictionary *info) {
            NSLog(@"result size:%@",NSStringFromCGSize(result.size));

            BOOL isRealDealForSure = NO;
            NSNumber* n = info[@"PHImageResultIsPlaceholderKey"]; //undocumented key so I don't count on it
            if (n != nil && [n boolValue] == NO){
                isRealDealForSure = YES;
            }

            if([info[PHImageResultIsInCloudKey] boolValue]){
                NSLog(@"image is in the cloud"); //never seen this. (because I allowed network access)
            }
            else if([info[PHImageResultIsDegradedKey] boolValue] && !isRealDealForSure){
                    //do something with the small image...but keep waiting
                [self.delegate choosePhotoCollectionVCPreviewSmallPhoto:result];
                self.collectionView.allowsSelection = YES;
                dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(3.0 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{ //random time of 3 seconds to get the full resolution in case the degraded key is lying to me. The user can move on but we will keep waiting.
                    if(isStillLookingForPhoto){
                        self.selectedImage = result;
                        [self.delegate choosePhotoCollectionVCPreviewFullPhoto:self.selectedImage]; //remove activity indicator and let the user move on
                    }
                });
            }
            else {
                    //do something with the full result and get rid of activity indicator.
                if(asset == self.selectedAsset){
                    isStillLookingForPhoto = NO;
                    self.selectedImage = result;
                    [self.delegate choosePhotoCollectionVCPreviewFullPhoto:self.selectedImage];
                    self.collectionView.allowsSelection = YES;
                }
                else {
                    NSLog(@"ignored asset because another was pressed");
                }
            }
        }];

Answer 3

要获得完整的大小图像，您需要检查信息列表。我用它来测试返回的结果是完整的图像，还是降级的版本。

if ([[info valueForKey:@"PHImageResultIsDegradedKey"]integerValue]==0){
    // Do something with the FULL SIZED image
} else {
    // Do something with the regraded image
}

或者你可以用这个来确认你是否得到了你要的东西。

if ([[info valueForKey:@"PHImageResultWantedImageFormatKey"]integerValue]==[[info valueForKey:@"PHImageResultDeliveredImageFormatKey"]integerValue]){
    // Do something with the FULL SIZED image
} else {
    // Do something with the regraded image
}

还有一些其他的，无证但有用的钥匙。

"/private/var/mobile/Media/DCIM/100APPLE/IMG_0780.JPG"；= 3；PHImageFileSandboxExtensionTokenKey = "file:///var/mobile/Media/DCIM/100APPLE/IMG_0780.JPG"；PHImageFileURLKey = "public.jpeg"；PHImageResultDeliveredImageFormatKey = 9999；PHImageResultIsDegradedKey = 0；PHImageResultIsInCloudKey = 0；PHImageResultIsPlaceholderKey = 0；PHImageResultRequestIDKey = 1；PHImageResultWantedImageFormatKey = 9999；

玩得开心。莱纳斯