文件的读写

文件的写入
     NSArray *paths = NSSearchPathForDirectoriesInDomains ( NSDocumentDirectory , NSUserDomainMask , YES );
    NSLog ( @"paths%@" ,paths);
    NSString *docDir = [paths objectAtIndex : 0 ];
    if (!docDir) {   // 假值
        NSLog ( @"Documents 目录未找到 " );
    }
    NSArray *array = [[ NSArray alloc ] initWithObjects : @" 内容 " , @"content" , nil ];
    NSString *filePath = [docDir stringByAppendingPathComponent : @"testFile.txt" ];
    [array writeToFile :filePath atomically : YES ]; // 将 array 写入 filePath 路径提供的文件

文件的读取
     NSArray *paths = NSSearchPathForDirectoriesInDomains ( NSDocumentDirectory , NSUserDomainMask , YES );
    NSString *docDir = [paths objectAtIndex : 0 ];
    NSString *filePath = [docDir stringByAppendingPathComponent : @"testFile.txt" ];
    NSArray *array = [[ NSArray alloc ] initWithContentsOfFile :filePath];
     NSLog ( @"%@" , array); //注意这里在输出时，中文会成为utf8格式的编码，如果使用消息方式不会

创建新目录以及在新目录下创建文件
     NSArray *paths = NSSearchPathForDirectoriesInDomains ( NSDocumentDirectory , NSUserDomainMask , YES );
    NSString *doucumentsDirectory = [paths objectAtIndex : 0 ];
    NSLog ( @"%@" ,doucumentsDirectory);
   
    NSFileManager *fileManager =[ NSFileManager defaultManager ];
    NSString *testDirectory = [doucumentsDirectory stringByAppendingPathComponent : @"test" ];
   

   
    [fileManager createDirectoryAtPath :testDirectory withIntermediateDirectories : YES attributes : Nil error : Nil ];    // 创建 test 目录
   
    NSString *testPath = [testDirectory stringByAppendingPathComponent : @"test00.txt" ];
    NSString *string = @" 写入内容 ,write String" ;
   
    [fileManager createFileAtPath :testPath contents :[string dataUsingEncoding : NSUTF8StringEncoding ] attributes : nil ]; // 创建文件以及写入内容
查看目录下所有文件
     NSArray *paths = NSSearchPathForDirectoriesInDomains ( NSDocumentDirectory , NSUserDomainMask , YES );
    NSString *documentsDirectory = [paths objectAtIndex : 0 ];
   
    NSFileManager *fileManage = [ NSFileManager defaultManager ];
    NSString *myDirectory = [documentsDirectory stringByAppendingPathComponent : @"test" ];
   
    NSArray *file = [fileManage subpathsOfDirectoryAtPath :myDirectory error : nil ]; //和下面的方法一样
    NSLog ( @"%@" ,file);
    NSArray *files =[fileManage subpathsAtPath :myDirectory];
     NSLog ( @"%@" ,files);
删除文件
     [fileManager removeItemAtPath :flieName error : nil ];