遍历目录下指定文件类型的文件，并输出

   [super viewDidLoad];    NSFileManager *fileManager = [NSFileManager defaultManager];    NSArray *path =NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);    NSString *file = [path objectAtIndex:0]; //获得Document系统文件目录路径    NSDirectoryEnumerator *direnum = [fileManager enumeratorAtPath:file ]; //遍历目录//    NSMutableArray *files = [NSMutableArray arrayWithCapacity:50];    NSMutableArray *files = [[NSMutableArray alloc] init];     NSString *fileName;    while((fileName = [direnum nextObject])){        if([[fileName pathExtension] isEqualToString:@"png"]){  //遍历条件            [files addObject:fileName];            NSLog(@"%@",fileName);        }    }