*:first-child {
margin-top: 0 !important; }
body > *:last-child {
margin-bottom: 0 !important; }

a {
color: #4183C4; }
a.absent {
color: #cc0000; }
a.anchor {
display: block;
padding-left: 30px;
margin-left: -30px;
cursor: pointer;
position: absolute;
top: 0;
left: 0;
bottom: 0; }

h1, h2, h3, h4, h5, h6 {
margin: 20px 0 10px;
padding: 0;
font-weight: bold;
-webkit-font-smoothing: antialiased;
cursor: text;
position: relative; }

h1:hover a.anchor, h2:hover a.anchor, h3:hover a.anchor, h4:hover a.anchor, h5:hover a.anchor, h6:hover a.anchor {
background: url(data:image/png;base64,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) no-repeat 10px center;
text-decoration: none; }

h1 tt, h1 code {
font-size: inherit; }

h2 tt, h2 code {
font-size: inherit; }

h3 tt, h3 code {
font-size: inherit; }

h4 tt, h4 code {
font-size: inherit; }

h5 tt, h5 code {
font-size: inherit; }

h6 tt, h6 code {
font-size: inherit; }

h1 {
font-size: 28px;
color: black; }

h2 {
font-size: 24px;
border-bottom: 1px solid #cccccc;
color: black; }

h3 {
font-size: 18px; }

h4 {
font-size: 16px; }

h5 {
font-size: 14px; }

h6 {
color: #777777;
font-size: 14px; }

p, blockquote, ul, ol, dl, li, table, pre {
margin: 15px 0; }

hr {
background: transparent url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAYAAAAECAYAAACtBE5DAAAAGXRFWHRTb2Z0d2FyZQBBZG9iZSBJbWFnZVJlYWR5ccllPAAAAyJpVFh0WE1MOmNvbS5hZG9iZS54bXAAAAAAADw/eHBhY2tldCBiZWdpbj0i77u/IiBpZD0iVzVNME1wQ2VoaUh6cmVTek5UY3prYzlkIj8+IDx4OnhtcG1ldGEgeG1sbnM6eD0iYWRvYmU6bnM6bWV0YS8iIHg6eG1wdGs9IkFkb2JlIFhNUCBDb3JlIDUuMC1jMDYwIDYxLjEzNDc3NywgMjAxMC8wMi8xMi0xNzozMjowMCAgICAgICAgIj4gPHJkZjpSREYgeG1sbnM6cmRmPSJodHRwOi8vd3d3LnczLm9yZy8xOTk5LzAyLzIyLXJkZi1zeW50YXgtbnMjIj4gPHJkZjpEZXNjcmlwdGlvbiByZGY6YWJvdXQ9IiIgeG1sbnM6eG1wPSJodHRwOi8vbnMuYWRvYmUuY29tL3hhcC8xLjAvIiB4bWxuczp4bXBNTT0iaHR0cDovL25zLmFkb2JlLmNvbS94YXAvMS4wL21tLyIgeG1sbnM6c3RSZWY9Imh0dHA6Ly9ucy5hZG9iZS5jb20veGFwLzEuMC9zVHlwZS9SZXNvdXJjZVJlZiMiIHhtcDpDcmVhdG9yVG9vbD0iQWRvYmUgUGhvdG9zaG9wIENTNSBNYWNpbnRvc2giIHhtcE1NOkluc3RhbmNlSUQ9InhtcC5paWQ6OENDRjNBN0E2NTZBMTFFMEI3QjRBODM4NzJDMjlGNDgiIHhtcE1NOkRvY3VtZW50SUQ9InhtcC5kaWQ6OENDRjNBN0I2NTZBMTFFMEI3QjRBODM4NzJDMjlGNDgiPiA8eG1wTU06RGVyaXZlZEZyb20gc3RSZWY6aW5zdGFuY2VJRD0ieG1wLmlpZDo4Q0NGM0E3ODY1NkExMUUwQjdCNEE4Mzg3MkMyOUY0OCIgc3RSZWY6ZG9jdW1lbnRJRD0ieG1wLmRpZDo4Q0NGM0E3OTY1NkExMUUwQjdCNEE4Mzg3MkMyOUY0OCIvPiA8L3JkZjpEZXNjcmlwdGlvbj4gPC9yZGY6UkRGPiA8L3g6eG1wbWV0YT4gPD94cGFja2V0IGVuZD0iciI/PqqezsUAAAAfSURBVHjaYmRABcYwBiM2QSA4y4hNEKYDQxAEAAIMAHNGAzhkPOlYAAAAAElFTkSuQmCC) repeat-x 0 0;
border: 0 none;
color: #cccccc;
height: 4px;
padding: 0;
}

body > h2:first-child {
margin-top: 0;
padding-top: 0; }
body > h1:first-child {
margin-top: 0;
padding-top: 0; }
body > h1:first-child + h2 {
margin-top: 0;
padding-top: 0; }
body > h3:first-child, body > h4:first-child, body > h5:first-child, body > h6:first-child {
margin-top: 0;
padding-top: 0; }

a:first-child h1, a:first-child h2, a:first-child h3, a:first-child h4, a:first-child h5, a:first-child h6 {
margin-top: 0;
padding-top: 0; }

h1 p, h2 p, h3 p, h4 p, h5 p, h6 p {
margin-top: 0; }

li p.first {
display: inline-block; }
li {
margin: 0; }
ul, ol {
padding-left: 30px; }

ul :first-child, ol :first-child {
margin-top: 0; }

dl {
padding: 0; }
dl dt {
font-size: 14px;
font-weight: bold;
font-style: italic;
padding: 0;
margin: 15px 0 5px; }
dl dt:first-child {
padding: 0; }
dl dt > :first-child {
margin-top: 0; }
dl dt > :last-child {
margin-bottom: 0; }
dl dd {
margin: 0 0 15px;
padding: 0 15px; }
dl dd > :first-child {
margin-top: 0; }
dl dd > :last-child {
margin-bottom: 0; }

blockquote {
border-left: 4px solid #dddddd;
padding: 0 15px;
color: #777777; }
blockquote > :first-child {
margin-top: 0; }
blockquote > :last-child {
margin-bottom: 0; }

table {
padding: 0;border-collapse: collapse; }
table tr {
border-top: 1px solid #cccccc;
background-color: white;
margin: 0;
padding: 0; }
table tr:nth-child(2n) {
background-color: #f8f8f8; }
table tr th {
font-weight: bold;
border: 1px solid #cccccc;
margin: 0;
padding: 6px 13px; }
table tr td {
border: 1px solid #cccccc;
margin: 0;
padding: 6px 13px; }
table tr th :first-child, table tr td :first-child {
margin-top: 0; }
table tr th :last-child, table tr td :last-child {
margin-bottom: 0; }

img {
max-width: 100%; }

span.frame {
display: block;
overflow: hidden; }
span.frame > span {
border: 1px solid #dddddd;
display: block;
float: left;
overflow: hidden;
margin: 13px 0 0;
padding: 7px;
width: auto; }
span.frame span img {
display: block;
float: left; }
span.frame span span {
clear: both;
color: #333333;
display: block;
padding: 5px 0 0; }
span.align-center {
display: block;
overflow: hidden;
clear: both; }
span.align-center > span {
display: block;
overflow: hidden;
margin: 13px auto 0;
text-align: center; }
span.align-center span img {
margin: 0 auto;
text-align: center; }
span.align-right {
display: block;
overflow: hidden;
clear: both; }
span.align-right > span {
display: block;
overflow: hidden;
margin: 13px 0 0;
text-align: right; }
span.align-right span img {
margin: 0;
text-align: right; }
span.float-left {
display: block;
margin-right: 13px;
overflow: hidden;
float: left; }
span.float-left span {
margin: 13px 0 0; }
span.float-right {
display: block;
margin-left: 13px;
overflow: hidden;
float: right; }
span.float-right > span {
display: block;
overflow: hidden;
margin: 13px auto 0;
text-align: right; }

code, tt {
margin: 0 2px;
padding: 0 5px;
white-space: nowrap;
border: 1px solid #eaeaea;
background-color: #f8f8f8;
border-radius: 3px; }

pre code {
margin: 0;
padding: 0;
white-space: pre;
border: none;
background: transparent; }

.highlight pre {
background-color: #f8f8f8;
border: 1px solid #cccccc;
font-size: 13px;
line-height: 19px;
overflow: auto;
padding: 6px 10px;
border-radius: 3px; }

pre {
background-color: #f8f8f8;
border: 1px solid #cccccc;
font-size: 13px;
line-height: 19px;
overflow: auto;
padding: 6px 10px;
border-radius: 3px; }
pre code, pre tt {
background-color: transparent;
border: none; }

sup {
font-size: 0.83em;
vertical-align: super;
line-height: 0;
}
* {
-webkit-print-color-adjust: exact;
}
@media screen and (min-width: 914px) {
body {
width: 854px;
margin:0 auto;
}
}
@media print {
table, pre {
page-break-inside: avoid;
}
pre {
word-wrap: break-word;
}
}
-->

NSNumber

本小节知识点:

【理解】NSNumber基本概念
【理解】NSNumber的创建
【理解】从NSNumber对象中的到基本类型数据

1.NSNumber基本概念

NSArray\NSDictionary中只能存放OC对象,不能存放int\float\double等基本数据类
如果真想把基本数据(比如int)放进数组或字典中,需要先将基本数据类型包装成OC对象
- NSNumber可以将基本数据类型包装成对象,这样就可以间接将基本数据类型存进NSArray\NSDictionary中

2.NSNumber的创建

以前

+ (NSNumber *)numberWithInt:(int)value;

+ (NSNumber *)numberWithDouble:(double)value;

+ (NSNumber *)numberWithBool:(BOOL)value;

现在 objc @10; @10.5; @YES; @(num);

3.从NSNumber对象中的到基本类型数据

- (char)charValue;

- (int)intValue;

- (long)longValue;

- (double)doubleValue;

- (BOOL)boolValue;

- (NSString *)stringValue;

- (NSComparisonResult)compare:(NSNumber *)otherNumber;

- (BOOL)isEqualToNumber:(NSNumber *)number;

*:first-child {
margin-top: 0 !important; }
body > *:last-child {
margin-bottom: 0 !important; }

a {
color: #4183C4; }
a.absent {
color: #cc0000; }
a.anchor {
display: block;
padding-left: 30px;
margin-left: -30px;
cursor: pointer;
position: absolute;
top: 0;
left: 0;
bottom: 0; }

h1, h2, h3, h4, h5, h6 {
margin: 20px 0 10px;
padding: 0;
font-weight: bold;
-webkit-font-smoothing: antialiased;
cursor: text;
position: relative; }

h1 tt, h1 code {
font-size: inherit; }

h2 tt, h2 code {
font-size: inherit; }

h3 tt, h3 code {
font-size: inherit; }

h4 tt, h4 code {
font-size: inherit; }

h5 tt, h5 code {
font-size: inherit; }

h6 tt, h6 code {
font-size: inherit; }

h1 {
font-size: 28px;
color: black; }

h2 {
font-size: 24px;
border-bottom: 1px solid #cccccc;
color: black; }

h3 {
font-size: 18px; }

h4 {
font-size: 16px; }

h5 {
font-size: 14px; }

h6 {
color: #777777;
font-size: 14px; }

p, blockquote, ul, ol, dl, li, table, pre {
margin: 15px 0; }

a:first-child h1, a:first-child h2, a:first-child h3, a:first-child h4, a:first-child h5, a:first-child h6 {
margin-top: 0;
padding-top: 0; }

h1 p, h2 p, h3 p, h4 p, h5 p, h6 p {
margin-top: 0; }

li p.first {
display: inline-block; }
li {
margin: 0; }
ul, ol {
padding-left: 30px; }

ul :first-child, ol :first-child {
margin-top: 0; }

blockquote {
border-left: 4px solid #dddddd;
padding: 0 15px;
color: #777777; }
blockquote > :first-child {
margin-top: 0; }
blockquote > :last-child {
margin-bottom: 0; }

img {
max-width: 100%; }

code, tt {
margin: 0 2px;
padding: 0 5px;
white-space: nowrap;
border: 1px solid #eaeaea;
background-color: #f8f8f8;
border-radius: 3px; }

pre code {
margin: 0;
padding: 0;
white-space: pre;
border: none;
background: transparent; }

.highlight pre {
background-color: #f8f8f8;
border: 1px solid #cccccc;
font-size: 13px;
line-height: 19px;
overflow: auto;
padding: 6px 10px;
border-radius: 3px; }

NSValue

本小节知识点:

【理解】NSValue基本概念
【理解】常见结构体的包装
【理解】任意数据的包装

1.NSValue基本概念

NSNumber是NSValue的子类, 但NSNumber只能包装数字类型
NSValue可以包装任意值
- 因此, 可以用NSValue将结构体包装后,加入NSArray\NSDictionary中

2. 常见结构体的包装

为了方便结构体和NSValue的转换,Foundation提供了以下方法
将结构体包装成NSValue对象

+ (NSValue *)valueWithPoint:(NSPoint)point;

+ (NSValue *)valueWithSize:(NSSize)size;

+ (NSValue *)valueWithRect:(NSRect)rect;

从NSValue对象取出之前包装的结构体

- (NSPoint)pointValue;

- (NSSize)sizeValue;

- (NSRect)rectValue;

3.任意数据的包装

NSValue提供了下列方法来包装任意数据

+ (NSValue *)valueWithBytes:(const void *)value objCType:(const char *)type;

+ value参数 : 所包装数据的地址

+ type参数 : 用来描述这个数据类型的字符串, 用@encode指令来生成

- 从NSValue中取出所包装的数据

- (void)getValue:(void *)value;

*:first-child {
margin-top: 0 !important; }
body > *:last-child {
margin-bottom: 0 !important; }

a {
color: #4183C4; }
a.absent {
color: #cc0000; }
a.anchor {
display: block;
padding-left: 30px;
margin-left: -30px;
cursor: pointer;
position: absolute;
top: 0;
left: 0;
bottom: 0; }

h1, h2, h3, h4, h5, h6 {
margin: 20px 0 10px;
padding: 0;
font-weight: bold;
-webkit-font-smoothing: antialiased;
cursor: text;
position: relative; }

h1 tt, h1 code {
font-size: inherit; }

h2 tt, h2 code {
font-size: inherit; }

h3 tt, h3 code {
font-size: inherit; }

h4 tt, h4 code {
font-size: inherit; }

h5 tt, h5 code {
font-size: inherit; }

h6 tt, h6 code {
font-size: inherit; }

h1 {
font-size: 28px;
color: black; }

h2 {
font-size: 24px;
border-bottom: 1px solid #cccccc;
color: black; }

h3 {
font-size: 18px; }

h4 {
font-size: 16px; }

h5 {
font-size: 14px; }

h6 {
color: #777777;
font-size: 14px; }

p, blockquote, ul, ol, dl, li, table, pre {
margin: 15px 0; }

a:first-child h1, a:first-child h2, a:first-child h3, a:first-child h4, a:first-child h5, a:first-child h6 {
margin-top: 0;
padding-top: 0; }

h1 p, h2 p, h3 p, h4 p, h5 p, h6 p {
margin-top: 0; }

li p.first {
display: inline-block; }
li {
margin: 0; }
ul, ol {
padding-left: 30px; }

ul :first-child, ol :first-child {
margin-top: 0; }

blockquote {
border-left: 4px solid #dddddd;
padding: 0 15px;
color: #777777; }
blockquote > :first-child {
margin-top: 0; }
blockquote > :last-child {
margin-bottom: 0; }

img {
max-width: 100%; }

code, tt {
margin: 0 2px;
padding: 0 5px;
white-space: nowrap;
border: 1px solid #eaeaea;
background-color: #f8f8f8;
border-radius: 3px; }

pre code {
margin: 0;
padding: 0;
white-space: pre;
border: none;
background: transparent; }

.highlight pre {
background-color: #f8f8f8;
border: 1px solid #cccccc;
font-size: 13px;
line-height: 19px;
overflow: auto;
padding: 6px 10px;
border-radius: 3px; }

NSDate

本小节知识点:

【理解】NSDate基本概念
【理解】格式化日期
【理解】日期时间对象

1.NSDate基本概念

NSDate可以用来表示时间, 可以进行一些常见的日期\时间处理
一个NSDate对象就代表一个时间
[NSDate date]返回的就是当前时间

    NSDate *now = [NSDate date];

    NSLog(@"now = %@", now);

     // 设置转换后的目标日期时区

     NSTimeZone *zone = [NSTimeZone systemTimeZone];

     // 得到源日期与世界标准时间的偏移量

     NSInteger interval = [zone secondsFromGMTForDate: date];

     NSLog(@"interval = %lu", interval);

     // 在当前时间基础上追加时区差值

     now = [now dateByAddingTimeInterval:interval];

     NSLog(@"%@", date);

2.格式化日期

NSDate -> NSString

    // 1.创建时间

    NSDate *now = [NSDate date];

    // 2.创建时间格式化

    NSDateFormatter *formatter = [[NSDateFormatter alloc] init];

    // 3.指定格式

    formatter.dateFormat = @"yyyy-MM-dd HH:mm:ss";

    // 4.格式化时间

    NSString *str = [formatter stringFromDate:now];

    NSLog(@"%@", str);

NSString -> NSDate

    NSString *str = @"2015-06-28 19:53:24";

    NSDateFormatter *formatter = [[NSDateFormatter alloc] init];

    formatter.dateFormat = @"yyyy-MM-dd HH:mm:ss";

    NSDate *date = [formatter dateFromString:str];

    NSLog(@"%@", date);

3.日期时间对象

结合NSCalendar和NSDate能做更多的日期\时间处理
获得NSCalendar对象

NSCalendar *calendar = [NSCalendar currentCalendar];

获得年月日

- (NSDateComponents *)components:(NSCalendarUnit)unitFlags fromDate:(NSDate *)date;

    NSDate *date = [NSDate date];

    // 1.创建日历对象

    NSCalendar *calendar = [NSCalendar currentCalendar];

    // 2.利用日历对象获取年月日时分秒

    NSCalendarUnit type = NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay | NSCalendarUnitHour | NSCalendarUnitMinute | NSCalendarUnitSecond;

    NSDateComponents *cmps =[calendar components:type fromDate:date];

    NSLog(@"year = %lu", cmps.year);

    NSLog(@"month = %lu", cmps.month);

    NSLog(@"day = %lu", cmps.day);

    NSLog(@"hour = %lu", cmps.hour);

    NSLog(@"minute = %lu", cmps.minute);

    NSLog(@"second = %lu", cmps.second);

    NSLog(@"date = %@", date);

比较两个日期的差距

- (NSDateComponents *)components:(NSCalendarUnit)unitFlags fromDate:(NSDate *)startingDate toDate:(NSDate *)resultDate options:(NSCalendarOptions)opts;

    // 1.确定时间

    NSString *time1 = @"2015-06-23 12:18:15";

    NSString *time2 = @"2015-06-28 10:10:10";

    // 2.将时间转换为date

    NSDateFormatter *formatter = [[NSDateFormatter alloc] init];

    formatter.dateFormat = @"yyyy-MM-dd HH:mm:ss";

    NSDate *date1 = [formatter dateFromString:time1];

    NSDate *date2 = [formatter dateFromString:time2];

    // 3.创建日历

    NSCalendar *calendar = [NSCalendar currentCalendar];

    NSCalendarUnit type = NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay | NSCalendarUnitHour | NSCalendarUnitMinute | NSCalendarUnitSecond;

    // 4.利用日历对象比较两个时间的差值

    NSDateComponents *cmps = [calendar components:type fromDate:date1 toDate:date2 options:0];

    // 5.输出结果

    NSLog(@"两个时间相差%ld年%ld月%ld日%ld小时%ld分钟%ld秒", cmps.year, cmps.month, cmps.day, cmps.hour, cmps.minute, cmps.second);

*:first-child {
margin-top: 0 !important; }
body > *:last-child {
margin-bottom: 0 !important; }

a {
color: #4183C4; }
a.absent {
color: #cc0000; }
a.anchor {
display: block;
padding-left: 30px;
margin-left: -30px;
cursor: pointer;
position: absolute;
top: 0;
left: 0;
bottom: 0; }

h1, h2, h3, h4, h5, h6 {
margin: 20px 0 10px;
padding: 0;
font-weight: bold;
-webkit-font-smoothing: antialiased;
cursor: text;
position: relative; }

h1 tt, h1 code {
font-size: inherit; }

h2 tt, h2 code {
font-size: inherit; }

h3 tt, h3 code {
font-size: inherit; }

h4 tt, h4 code {
font-size: inherit; }

h5 tt, h5 code {
font-size: inherit; }

h6 tt, h6 code {
font-size: inherit; }

h1 {
font-size: 28px;
color: black; }

h2 {
font-size: 24px;
border-bottom: 1px solid #cccccc;
color: black; }

h3 {
font-size: 18px; }

h4 {
font-size: 16px; }

h5 {
font-size: 14px; }

h6 {
color: #777777;
font-size: 14px; }

p, blockquote, ul, ol, dl, li, table, pre {
margin: 15px 0; }

a:first-child h1, a:first-child h2, a:first-child h3, a:first-child h4, a:first-child h5, a:first-child h6 {
margin-top: 0;
padding-top: 0; }

h1 p, h2 p, h3 p, h4 p, h5 p, h6 p {
margin-top: 0; }

li p.first {
display: inline-block; }
li {
margin: 0; }
ul, ol {
padding-left: 30px; }

ul :first-child, ol :first-child {
margin-top: 0; }

blockquote {
border-left: 4px solid #dddddd;
padding: 0 15px;
color: #777777; }
blockquote > :first-child {
margin-top: 0; }
blockquote > :last-child {
margin-bottom: 0; }

img {
max-width: 100%; }

code, tt {
margin: 0 2px;
padding: 0 5px;
white-space: nowrap;
border: 1px solid #eaeaea;
background-color: #f8f8f8;
border-radius: 3px; }

pre code {
margin: 0;
padding: 0;
white-space: pre;
border: none;
background: transparent; }

.highlight pre {
background-color: #f8f8f8;
border: 1px solid #cccccc;
font-size: 13px;
line-height: 19px;
overflow: auto;
padding: 6px 10px;
border-radius: 3px; }

NSFileManager

本小节知识点:

【理解】NSFileManager介绍
【理解】NSFileManager用法(常见的判断)
【理解】NSFileManager的文件访问
【理解】NSFileManager的文件操作

1.NSFileManager介绍

什么是NSFileManager
- 顾名思义, NSFileManager是用来管理文件系统的
- 它可以用来进行常见的文件\文件夹操作
NSFileManager使用了单例模式
- 使用defaultManager方法可以获得那个单例对象 objc [NSFileManager defaultManager]

2.NSFileManager用法

- (BOOL)fileExistsAtPath:(NSString *)path;
- path这个文件\文件夹是否存在

    NSFileManager *manager = [NSFileManager defaultManager];

    // 可以判断文件

    BOOL flag = [manager fileExistsAtPath:@"/Users/LNJ/Desktop/lnj.txt"];

    NSLog(@"flag = %i", flag);

    // 可以判断文件夹

    flag = [manager fileExistsAtPath:@"/Users/LNJ/Desktop/未命名文件夹"];

    NSLog(@"flag = %i", flag);

- (BOOL)fileExistsAtPath:(NSString *)path isDirectory:(BOOL *)isDirectory;
- path这个文件\文件夹是否存在, isDirectory代表是否为文件夹

    NSFileManager *manager = [NSFileManager defaultManager];

    BOOL directory = NO;

    BOOL flag = [manager fileExistsAtPath:@"/Users/LNJ/Desktop/未命名文件夹" isDirectory:&directory];

    NSLog(@"flag = %i, directory = %i", flag, directory);

- (BOOL)isReadableFileAtPath:(NSString *)path;
- path这个文件\文件夹是否可读
- (BOOL)isWritableFileAtPath:(NSString *)path;
- path这个文件\文件夹是否可写
- 系统目录不允许写入
- (BOOL)isDeletableFileAtPath:(NSString *)path;
- path这个文件\文件夹是否可删除
- 系统目录不允许删除

3.NSFileManager的文件访问

- (NSDictionary *)attributesOfItemAtPath:(NSString *)path error:(NSError **)error;
- 获得path这个文件\文件夹的属性

    NSFileManager *manager = [NSFileManager defaultManager];

    NSDictionary *dict = [manager attributesOfItemAtPath:@"/Users/LNJ/Desktop/lnj.txt" error:nil];

    NSLog(@"dit = %@", dict);

- (NSArray *)contentsOfDirectoryAtPath:(NSString *)path error:(NSError **)error;
- 获得path的当前子路径
- (NSData *)contentsAtPath:(NSString *)path;
- 获得文件内容

    NSFileManager *manager = [NSFileManager defaultManager];

    NSArray *paths = [manager contentsOfDirectoryAtPath:@"/Users/LNJ/Desktop/" error:nil];

    NSLog(@"paths = %@", paths);

- (NSArray *)subpathsAtPath:(NSString *)path;
- (NSArray *)subpathsOfDirectoryAtPath:(NSString *)path error:(NSError **)error;
- 获得path的所有子路径

    NSFileManager *manager = [NSFileManager defaultManager];

    NSArray *paths = [manager subpathsAtPath:@"/Users/LNJ/Desktop/"];

    NSLog(@"paths = %@", paths);

4.NSFileManager的文件操作

- (BOOL)copyItemAtPath:(NSString *)srcPath toPath:(NSString *)dstPath error:(NSError **)error;
- 拷贝
- (BOOL)moveItemAtPath:(NSString *)srcPath toPath:(NSString *)dstPath error:(NSError **)error;
- 移动(剪切)
- (BOOL)removeItemAtPath:(NSString *)path error:(NSError **)error;
- 删除
- (BOOL)createDirectoryAtPath:(NSString *)path withIntermediateDirectories:(BOOL)createIntermediates attributes:(NSDictionary *)attributes error:(NSError **)error;
- 创建文件夹(createIntermediates为YES代表自动创建中间的文件夹)

    NSFileManager *manager = [NSFileManager defaultManager];

    BOOL flag = [manager createDirectoryAtPath:@"/Users/LNJ/Desktop/test" withIntermediateDirectories:YES attributes:nil error:nil];

    NSLog(@"flag = %i", flag);

- (BOOL)createFileAtPath:(NSString *)path contents:(NSData *)data attributes:(NSDictionary *)attr;
- 创建文件(NSData是用来存储二进制字节数据的)

    NSString *str = @"lnj";

    NSData  *data = [str dataUsingEncoding:NSUTF8StringEncoding];

    NSFileManager *manager = [NSFileManager defaultManager];

    BOOL flag = [manager createFileAtPath:@"/Users/LNJ/Desktop/abc.txt" contents:data attributes:nil];

    NSLog(@"flag = %i", flag);

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NSValue

本小节知识点:

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NSFileManager

本小节知识点:

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