iOS遍历相册中所有照片，并获取其属性

 //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];
  }
 
});
 }