-(NSArray*)fileNames:(NSString*)fileName {
    NSString* path=[NSHomeDirectory() stringByAppendingPathComponent:@"Documents"];
    path=[path stringByAppendingPathComponent:fileName]; 
    return [[NSFileManager defaultManager] contentsOfDirectoryAtPath:path error:nil];
}
-(void)traceAllFiles{
    NSArray*t=[self fileNames:@""];
    NSLog(@"traceAllFiles %@",[t description]);
}
[self traceAllFiles];