iOS 使用系統相冊獲取選取圖片的名稱

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary<NSString *,id> *)info{
    
    NSString *mediaType = [info objectForKey:UIImagePickerControllerMediaType];
    //1.選擇的是圖片資源
    if ([mediaType isEqualToString:@"public.image"]) {

　　　　　　if (img !=nil) {

            //獲取圖片的名字

            __block NSString* imageFileName;

            NSURL *imageURL = [info valueForKey:UIImagePickerControllerReferenceURL];

            NSLog(@"imgurl:%@",imageURL);

            __weak typeof(self) weakSelf = self;

            ALAssetsLibraryAssetForURLResultBlock resultblock = ^(ALAsset *myasset)

            {

                ALAssetRepresentation *representation = [myasset defaultRepresentation];

                imageFileName = [representation filename];

            };

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

            [assetslibrary assetForURL:imageURL

                           resultBlock:resultblock

                          failureBlock:nil];

        }

    }
}