ios-获取系统相簿里边的所有照片

#import <AssetsLibrary/AssetsLibrary.h>

-(void)getImgs{
   
    dispatch_async(dispatch_get_main_queue(), ^{
        NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
       
       
        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
/*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
*/
                   
                  [self._dataArray addObject:urlstr];
                }
            }
          
        };
        ALAssetsLibraryGroupsEnumerationResultsBlock
        libraryGroupsEnumeration = ^(ALAssetsGroup* group, BOOL* stop){
           
            if (group == nil)
   &n