objective c - How to retrieve the most recent photo from Camera Roll on iOS?

Question

I'm having a hard figuring out how to programmatically retrieve the most recent photo in the camera roll without user intervention. To be clear, I do not want to use an Image Picker, I want the app to automatically grab the newest photo when the app opens.

I know this is possible because Ive seen a similar app do it, but I cant seem to find any info on it.

Answer 1

One way is to use AssetsLibrary and use n - 1 as the index for enumeration.

ALAssetsLibrary *assetsLibrary = [[ALAssetsLibrary alloc] init];
[assetsLibrary enumerateGroupsWithTypes:ALAssetsGroupSavedPhotos
                             usingBlock:^(ALAssetsGroup *group, BOOL *stop) {
                                 if (nil != group) {
                                     // be sure to filter the group so you only get photos
                                     [group setAssetsFilter:[ALAssetsFilter allPhotos]];

                                     if (group.numberOfAssets > 0) {
                                         [group enumerateAssetsAtIndexes:[NSIndexSet indexSetWithIndex:group.numberOfAssets - 1]
                                                                 options:0
                                                              usingBlock:^(ALAsset *result, NSUInteger index, BOOL *stop) {
                                                                  if (nil != result) {
                                                                      ALAssetRepresentation *repr = [result defaultRepresentation];
                                                                      // this is the most recent saved photo
                                                                      UIImage *img = [UIImage imageWithCGImage:[repr fullResolutionImage]];
                                                                      // we only need the first (most recent) photo -- stop the enumeration
                                                                      *stop = YES;
                                                                  }
                                                              }];
                                     }
                                 }

                                 *stop = NO;
                             } failureBlock:^(NSError *error) {
                                 NSLog(@"error: %@", error);
                             }];