iOS進(jìn)階

1：數(shù)據(jù)處理之?dāng)?shù)據(jù)讀寫

1):獲取當(dāng)前應(yīng)用程序的沙盒根目錄

NSString*rootPath = NSHomeDirectory();

NSLog(@"%@",rootPath);

rootPath就是根目錄

然后將打印出來(lái)的文件目錄右鍵單擊選擇services下的Reveal In Finder

2):

Documents：存儲(chǔ)持久化文件數(shù)據(jù)

Library/Caches：存儲(chǔ)緩存數(shù)據(jù)

Library/Preferences：存儲(chǔ)應(yīng)用的所有偏好設(shè)置

tmp：保存應(yīng)用運(yùn)行時(shí)所需的臨時(shí)數(shù)據(jù)

3):定位當(dāng)前應(yīng)用程序的沙盒根目錄

//1.Documents

NSString*docPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) firstObject];

NSLog(@"%@",docPath);

//2.library

NSString*libPath = [NSSearchPathForDirectoriesInDomains(NSLibraryDirectory, NSUserDomainMask, YES) firstObject];

NSLog(@"libPath is %@",libPath);

//3.library/Caches

NSString*cachesPath = [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) firstObject];

NSLog(@"cachesPath is %@",cachesPath);

//4.library/preferences ? 只能用拼接方法定位

NSString*prePath = [libPath stringByAppendingPathComponent:@"Preferences"];

NSLog(@"prePath is %@",prePath);

//5.tmp

NSString*tmpPath = NSTemporaryDirectory();

NSLog(@"tmpPath is %@",tmpPath);

4)：存儲(chǔ)應(yīng)用程序的偏好設(shè)置的類：NSUserDefaults

NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults] ;

[defaults setObject:@"tang" forKey:@"name"] ;

//同步

[defaults synchronize] ;

NSLog(@"%@",[defaults objectForKey:@"name"]);

5)：簡(jiǎn)單對(duì)象的讀寫操作

只有四種簡(jiǎn)單的數(shù)據(jù)類型才能直接寫入進(jìn)文件

NSString NSDictionary NSData NSArray

第一步：獲取沙盒下文件夾Documents的路徑

NSString*docPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject];

第二步：創(chuàng)建需要寫入的文件路徑

NSString*filePath = [docPath stringByAppendingString:@"/text.txt"];

第三步：創(chuàng)建字符串對(duì)象

NSString*string = @"is副科級(jí)領(lǐng)導(dǎo)蓋房了";

第四步：寫入，四種簡(jiǎn)單的數(shù)據(jù)類型的寫入方法差不多的

[string writeToFile:filePath atomically:YESencoding:NSUTF8StringEncodingerror:nil];

第五步：讀取字符串對(duì)象

NSString*resultStr = [NSStringstringWithContentsOfFile:filePath encoding:NSUTF8StringEncodingerror:nil];

數(shù)組和字典可參照字符串對(duì)象的寫入讀取方法

*NSData對(duì)象的寫入和讀取(將圖片存儲(chǔ))

第一步和第二步是一樣的

第三步：UIImage*image = [UIImageimageNamed:@"0"];

第四步：NSData*data = UIImagePNGRepresentation(image);

第五步：寫入

[data writeToFile:dataPath atomically:YES];

讀取圖片并在模擬器上顯示:

NSData*resultData = [NSDatadataWithContentsOfFile:dataPath];

UIImage*reImage = [UIImageimageWithData:resultData];

UIImageView*imageView = [[UIImageViewalloc] initWithImage:reImage];

imageView.frame= self.view.bounds;

[self.viewaddSubview:imageView];

6)：在沙盒目錄下創(chuàng)建文件

第一步：找到沙盒路徑(caches)

//1.獲取Documents目錄

NSString*docPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject];

//2.創(chuàng)建文件路徑

NSString*filePath = [docPath stringByAppendingString:@"/baobao.txt"];

//3.創(chuàng)建文件管理對(duì)象

NSFileManager*manager = [NSFileManagerdefaultManager];

//4.創(chuàng)建

[manager createFileAtPath:filePath contents:[@"sdfasdfs"dataUsingEncoding:NSUTF8StringEncoding] attributes:nil];

NSLog(@"%@",filePath);

//計(jì)算文件或文件夾的大小

NSDictionary*dic = [manager attributesOfItemAtPath:filePath error:nil];

NSLog(@"%@",dic);

NSNumber*number = [dic objectForKey:NSFileSize];

NSLog(@"%@",number);

7)：創(chuàng)建文件夾和創(chuàng)建文件的核心代碼差別在：

a：文件夾路徑?jīng)]有后綴名，文件有

b：文件管理器創(chuàng)建方法的不同

//2.創(chuàng)建文件夾的路徑

NSString*filePath = [cachesPath stringByAppendingString:@"/text"];

//3.創(chuàng)建文件管理器對(duì)象

NSFileManager*manager = [NSFileManagerdefaultManager];

[manager createDirectoryAtPath:filePath withIntermediateDirectories:YESattributes:nilerror:nil];

/*

在Documents文件夾下,創(chuàng)建一個(gè)文件夾(path),在該文件夾下創(chuàng)建一個(gè)文件(test.txt),將一個(gè)圖片對(duì)象存入到該文件中,然后在Caches文件夾下創(chuàng)建一個(gè)文件夾名為"testDirectroy",將test.txt文件復(fù)制到這個(gè)文件夾下.

*/

- (void)moveFile {

//1.獲取Documents目錄

NSString*docPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject];

//2.創(chuàng)建文件夾路徑

NSString*filePath = [docPath stringByAppendingString:@"/path"];

NSFileManager*manager = [NSFileManagerdefaultManager];

[manager createDirectoryAtPath:filePath withIntermediateDirectories:YESattributes:nilerror:nil];

//3.創(chuàng)建文件路徑

NSString*testPath = [filePath stringByAppendingString:@"/test.txt"];

[manager createFileAtPath:testPath contents:[@"aa"dataUsingEncoding:NSUTF8StringEncoding] attributes:nil];

//4.寫入圖片

UIImage*image = [UIImageimageNamed:@"0"];

NSData*data = UIImagePNGRepresentation(image);

[data writeToFile:testPath atomically:YES];

//5.caches目錄

NSString*cachesPath = [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) lastObject];

//6.創(chuàng)建文件夾testDirectroy

NSString*directoryPath = [cachesPath stringByAppendingPathComponent:@"testDirectroy"];

[manager createDirectoryAtPath:directoryPath withIntermediateDirectories:YESattributes:nilerror:nil];

//7創(chuàng)建一個(gè)和documents中需要復(fù)制的文件同名的文件

NSString*desPath = [directoryPath stringByAppendingString:@"/test.txt"];

//8.復(fù)制時(shí)需要?jiǎng)?chuàng)建文件管理器

[manager copyItemAtPath:testPath toPath:desPath error:nil];

NSLog(@"%@",directoryPath);

}

/*

練習(xí)要求：

在Documents目錄下創(chuàng)建一個(gè)文件text.txt

從文件的偏移量為3的時(shí)候開(kāi)始追加內(nèi)容1234

*/

- (void)addContent {

//1.得到Documents目錄

NSString*docPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject];

//2.創(chuàng)建文件夾路徑

NSString*filePath = [docPath stringByAppendingPathComponent:@"fiel"];

NSFileManager*manager = [NSFileManagerdefaultManager];

[manager createDirectoryAtPath:filePath withIntermediateDirectories:YESattributes:nilerror:nil];

//3.創(chuàng)建文件路徑

NSString*textPath = [filePath stringByAppendingPathComponent:@"/text.txt"];

[manager createFileAtPath:textPath contents:[@"hahahahahaha"dataUsingEncoding:NSUTF8StringEncoding] attributes:nil];

//4.創(chuàng)建文件對(duì)接器

NSFileHandle*handle = [NSFileHandlefileHandleForUpdatingAtPath:textPath];

//此時(shí)文件在更新?tīng)顟B(tài)下，即可讀也可寫

[handle seekToFileOffset:3];

//5.開(kāi)始在偏移量為3的地方寫入字符串

[handle writeData:[@"1234"dataUsingEncoding:NSUTF8StringEncoding]];

[handle closeFile];

NSLog(@"%@",textPath);

}

//核心代碼如下

//創(chuàng)建文件對(duì)接對(duì)象

NSFileHandle*handle = [NSFileHandlefileHandleForUpdatingAtPath:filePath];

//此時(shí)的文件對(duì)接對(duì)象既可以讀也可以寫

//將偏移量移動(dòng)到3的位置

[handle seekToFileOffset:3];

//寫入數(shù)據(jù)

[handle writeData:[@"1"dataUsingEncoding:NSUTF8StringEncoding]];

//執(zhí)行完操作之后不要忘了關(guān)閉文件

[handle closeFile];

8)：復(fù)雜文件的歸檔和反歸檔(持久化操作)

//歸檔

- (void)archiver {

//1.創(chuàng)建person對(duì)象

Person*p1 = [[Personalloc] initWithName:@"tangxi"age:@"18"];

Person*p2 = [[Personalloc] initWithName:@"aren"age:@"20"];

//2.獲取Documents目錄

NSString*docPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject];

NSString*filePath = [docPath stringByAppendingString:@"/haha.txt"];

//3.創(chuàng)建可變數(shù)據(jù)對(duì)象

NSMutableData*data = [NSMutableDatadata];

//4.創(chuàng)建歸檔類的對(duì)象

NSKeyedArchiver*archiver = [[NSKeyedArchiveralloc] initForWritingWithMutableData:data];

//5.將person對(duì)象歸檔

[archiver encodeObject:p1 forKey:@"person1"];

[archiver encodeObject:p2 forKey:@"person2"];

//6.結(jié)束歸檔

[archiver finishEncoding];//此時(shí)不管有幾個(gè)對(duì)象沒(méi)有被歸檔都會(huì)停止歸檔了

//7.將可變數(shù)據(jù)data寫入創(chuàng)建的文件

[data writeToFile:filePath atomically:YES];

NSLog(@"%@",filePath);

}

//反歸檔

- (void)unarchiver {

//1.獲取Documents目錄

NSString*documents = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject];

NSString*filePath = [documents stringByAppendingPathComponent:@"haha.txt"];

NSData*data = [NSDatadataWithContentsOfFile:filePath];

NSKeyedUnarchiver*unarchiver = [[NSKeyedUnarchiveralloc] initForReadingWithData:data];

Person*person = [unarchiver decodeObjectForKey:@"person1"];

NSLog(@"name is %@, age is %@",person.name,person.age);

[unarchiver finishDecoding];

}

//還要?jiǎng)?chuàng)建一個(gè)模型對(duì)象Person,遵循NSCoding協(xié)議

實(shí)現(xiàn)兩個(gè)協(xié)議方法:

- (instancetype)initWithName:(NSString*)name age:(NSString*)age {

self= [superinit];

if(self) {

self.name= name;

self.age= age;

}

returnself;

}

- (void)encodeWithCoder:(NSCoder*)aCoder {

[aCoder encodeObject:self.nameforKey:@"name"];

[aCoder encodeObject:self.ageforKey:@"age"];

}

- (nullableinstancetype)initWithCoder:(NSCoder*)aDecoder {

NSString*name = [aDecoder decodeObjectForKey:@"name"];

NSString*age = [aDecoder decodeObjectForKey:@"age"];

return[selfinitWithName:name age:age];

}

//4.寫入圖片

UIImage*image = [UIImageimageNamed:@"0"];

NSData*data = UIImagePNGRepresentation(image);

[data writeToFile:testPath atomically:YES];

//4.創(chuàng)建文件對(duì)接器

NSFileHandle*handle = [NSFileHandlefileHandleForUpdatingAtPath:textPath];

//此時(shí)文件在更新?tīng)顟B(tài)下，即可讀也可寫

[handle seekToFileOffset:3];

//5.開(kāi)始在偏移量為3的地方寫入字符串

[handle writeData:[@"1234"dataUsingEncoding:NSUTF8StringEncoding]];

[handle closeFile];

NSLog(@"%@",textPath);

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