ios-senior1-Data Processing (file read/write)

Understanding of the 1.Model data layer

1.1 Sandbox Basics

Sandbox definition: Each iOS application creates a file system directory (folder) for itself, a separate, closed, secure space called a sandbox.

Sandbox features:

Sandbox folders and the role of individual folders

Two ways to find a sandbox:

1. Click Finder, go to (upper-left corner)-> hold the ALT key, Developer, Coresimulator, and so on (destination folder)

2. Search-and-end command line:

Display: Defaults write Com.apple.finder appleshowallfiles-bool true
Hidden: Defaults write Com.apple.finder Appleshowallfiles-bool false

1.2 Data localization Knowledge points

Data localization definitions and how:

2. File read/write (storage)

2.1 Simple data types are written locally (strings, arrays, dictionaries, nsdata types of data stored locally) Nsstring,nsarray (for example, string)

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Operation Result :

2.2 (store NSData type of data) Read image write Local

The code is as follows:

Operation Result :

2.3 Complex objects stored locally (person)

The source code is as follows:

In the Person.h file:

Name

@property (nonatomic,copy) NSString *name;

Gender

@property (nonatomic,copy) NSString *gender;

Age

@property (nonatomic,assign) Nsinteger age;

In the person.m file:

Archive: Archive all attributes

-(void)encodewithcoder:(Nscoder *) Acoder {

[Acoder encodeObject:self.name forkey:@ "name"];

[Acoder encodeObject:self.gender forkey:@ "gender"];

[Acoder encodeInteger:self.age forkey:@ "age"];

}

Solution (Reverse archive)

-(instancetype)initwithcoder:(Nscoder *) Adecoder {

self = [super init];

if (self) {

Self.name = [Adecoder decodeobjectforkey: @ "name"];

Self.gender = [Adecoder decodeobjectforkey: @ "gender"];

Self.age = [Adecoder decodeintegerforkey: @ "age"];

}

return self;

}

in the viewcontroller.m file :

How to store objects of a person type locally, that is, for the localization of complex objects, this object must adhere to the Nscoding protocol and implement two methods in the Protocol

#pragma mark-Localization of complex objects

#pragma mark-Archive process

1. Find the directory of Documents folder

NSString *documentpath = [Nssearchpathfordirectoriesindomains (nsdocumentdirectory, NSUserDomainMask, YES) OBJECTATINDEX:0];

2. Create a Person object

Person *person = [[Person alloc]init];

Person.name = @ "Mbboy";

Person.gender = @ "Boy";

Person.age = 18;

3. Archive this object

3.1 Create Nsmutabledata, used to initialize the archive tool

Nsmutabledata *data = [Nsmutabledata data];

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

3.2 Creating an archive tool

Nskeyedarchiver *archiver = [[Nskeyedarchiver alloc]initforwritingwithmutabledata:data];

3.3 Archive The Person object to be archived

[Archiver encodeobject:person forkey:@ "person"];

3.4 End Archive

[Archiver finishencoding];

NSLog (@ "data1 =%@", data);

4. Store archived content on-premises

NSString *personpath = [documentpath stringbyappendingpathcomponent:@ "Person.plist"];

Write path

[Data Writetofile:personpath Atomically:yes];

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

#pragma mark-The process of unlocking the document

1. Find the data that will be solved

NSData *resultdata = [NSData Datawithcontentsoffile:personpath];

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

2. Create a profile tool

Nskeyedunarchiver *unarchiver = [[Nskeyedunarchiver alloc]initforreadingwithdata:resultdata];

3. Document the Person object [receive with an object, return value]

Person *newperson = [unarchiver decodeobjectforkey:@ ' person '];

4. End the solution

[Unarchiver finishdecoding];

NSLog (@ "name =%@,gender =%@,age =%ld", newperson.name,newperson.gender,newperson.age);

Operation Result :

"Let's do an exercise, let's do it."

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ios-senior1-Data Processing (file read/write)