Objective-C Foundation 框架    Example ：Looking for Files  查找文件

NSFileManager. The NSFileManager class lets you do stuff with the file system, like create directories, remove files, move files around, and get information about files.

 NSFileManager：让你处理一些文件系统的事情，比如创建目录，移除文件，移动文件，获取文件的信息。

//

//  main.m

//  Helloworld

//

//  Created by kfx on 15-5-4.

//  Copyright (c) 2015年 com.MySuperCompany. All rights reserved.

//

 

#import <Foundation/Foundation.h>

 

int main(int argc, const char * argv[]) {

    @autoreleasepool {

        NSFileManager *manager;

        manager = [NSFileManager defaultManager];

          

        NSString *home;

        home = [@"~" stringByExpandingTildeInPath];

          

        NSDirectoryEnumerator *direnum;//目录枚举

        direnum = [manager enumeratorAtPath:home];

          

        NSMutableArray *files;

        files = [NSMutableArray arrayWithCapacity:42];

          

        NSString *filename;

        while (filename = [direnum nextObject])

        {

            if ([[filename pathExtension] isEqualTo: @"jpg"]) {

                [files addObject: filename];

            } }

        NSEnumerator *fileenum;

        fileenum = [files objectEnumerator];

        while (filename = [fileenum nextObject])

        {

            NSLog (@"%@", filename);

        }    }

    return 0;

}

    return 0;

}

where in the file system to start looking at files？

Starting from the top level of your hard drive could take a long time, so let's just look in your home directory.

在home目录下开始。

Luckily, Unix (and OS X) has a shorthand character for the home directory, which is ~ (also known as the tilde).

unix 和os x 有一个简单地字符串代表home 目录。