iOS遍历相册中所有照片，并获取其属性

<pre>
//获取相册的所有图片

• (void)reloadImagesFromLibrary
  {
  self.images = [[NSMutableArray alloc] init];
  dispatch_async(dispatch_get_main_queue(), ^{
  @autoreleasepool {
  ALAssetsLibraryAccessFailureBlock failureblock = ^(NSError *myerror){
  NSLog(@"相册访问失败 =%@", [myerror localizedDescription]);
  if ([myerror.localizedDescription rangeOfString:@"Global denied access"].location!=NSNotFound) {
  NSLog(@"无法访问相册.请在'设置->定位服务'设置为打开状态.");
  }else{
  NSLog(@"相册访问失败.");
  }
  };

        ALAssetsGroupEnumerationResultsBlock groupEnumerAtion = ^(ALAsset *result, NSUInteger index, BOOL *stop){
            if (result!=NULL) {
                 
                if ([[result valueForProperty:ALAssetPropertyType] isEqualToString:ALAssetTypePhoto]) {
                     
                    NSString *urlstr=[NSString stringWithFormat:@"%@",result.defaultRepresentation.url];//图片的url
                    [self.images addObject:urlstr];
                    //NSLog(@"urlStr is %@",urlstr);
                    //result.defaultRepresentation.fullScreenImage//图片的大图
                    //result.thumbnail                             //图片的缩略图小图
                    NSRange range1=[urlstr rangeOfString:@"id="];
                    NSString *resultName=[urlstr substringFromIndex:range1.location+3];
                   resultName=[resultName stringByReplacingOccurrencesOfString:@"&ext=" withString:@"."];//格式demo:123456.png
                    
                }
            }
        };
         
        ALAssetsLibraryGroupsEnumerationResultsBlock libraryGroupsEnumeration = ^(ALAssetsGroup* group, BOOL* stop){
             
            if (group == nil)
            {
                 
            }
             
            if (group!=nil) {
                NSString *g=[NSString stringWithFormat:@"%@",group];//获取相簿的组
                NSLog(@"gg:%@",g);//gg:ALAssetsGroup - Name:Camera Roll, Type:Saved Photos, Assets count:71
                 
                NSString *g1=[g substringFromIndex:16 ] ;
                NSArray *arr=[[NSArray alloc] init];
                arr=[g1 componentsSeparatedByString:@","];
                NSString *g2=[[arr objectAtIndex:0] substringFromIndex:5];
                if ([g2 isEqualToString:@"Camera Roll"]) {
                    g2=@"相机胶卷";
                }
                NSString *groupName=g2;//组的name
                 
                [group enumerateAssetsUsingBlock:groupEnumerAtion];
            }
             
        };
         
        ALAssetsLibrary* library = [[ALAssetsLibrary alloc] init];
        [library enumerateGroupsWithTypes:ALAssetsGroupAll
                               usingBlock:libraryGroupsEnumeration
                             failureBlock:failureblock];
    }
  

  });
  }
  </pre>