//要排序的本地文件夹路径
NSString *ImageSaveDic = @"";
//文件夹中的文件路径
NSArray *localNames = [[NSFileManager defaultManager] subpathsAtPath:ImageSaveDic];
localNames = [localNames sortedArrayUsingComparator:^NSComparisonResult(NSString * firstPath, NSString* secondPath) {
NSString *firstUrl = [ImageSaveDic stringByAppendingPathComponent:firstPath];//获取前一个文件完整路径
NSString *secondUrl = [ImageSaveDic stringByAppendingPathComponent:secondPath];//获取后一个文件完整路径
NSDictionary *firstFileInfo = [[NSFileManager defaultManager] attributesOfItemAtPath:firstUrl error:nil];//获取前一个文件信息
NSDictionary *secondFileInfo = [[NSFileManager defaultManager] attributesOfItemAtPath:secondUrl error:nil];//获取后一个文件信息
id firstData = [firstFileInfo objectForKey:NSFileModificationDate];//获取前一个文件修改时间
id secondData = [secondFileInfo objectForKey:NSFileModificationDate];//获取后一个文件修改时间
// return [firstData compare:secondData];//升序
return [secondData compare:firstData];//降序
}];