Three kinds of data storage (Plist,nsuserdefaults storage, Nskeyedarchiver model method)

plist : General Storage General objects: NSString, dictionaries, arrays, NSData

First, the first to set 2 buttons, the basic knowledge, it is not written in this, the direct Write button trigger event to store and read

-(Ibaction) Save

{

1. Get the Sandbox root path

NSString *home = Nshomedirectory ();

2.document Path

NSString *docpath = [Home stringbyappendingpathcomponent:@ "Documents"];

3. New data

Nsarray *data = @[@ "Jack", @10, @ "FFDSF"];

NSString *filepath = [DocPath stringbyappendingpathcomponent:@ "Data.plist"];

[Data Writetofile:filepath Atomically:yes];

}

Read button

-(ibaction) Read {

1. Get the Sandbox root path

NSString *home = Nshomedirectory ();

2.document Path

NSString *docpath = [Home stringbyappendingpathcomponent:@ "Documents"];

3. File path

NSString *filepath = [DocPath stringbyappendingpathcomponent:@ "Data.plist"];

4. Reading data

Nsarray *data = [Nsarray Arraywithcontentsoffile:filepath];

NSLog (@ "%@", data);

}

Nsuserdefault Storage

-(ibaction) Save {

1. Direct access to Software preferences (library/preferences) with Nsuserdefaults

Nsuserdefaults *defaults = [Nsuserdefaults standarduserdefaults];

2. Storing data

[Defaults setobject:@ "MJ" forkey:@ "account"];

[Defaults setobject:@ "123" forkey:@ "pwd"];

[Defaults setinteger:10 forkey:@ "age"];

[Defaults setbool:yes forkey:@ "Auto_login"];

3. Sync now

[Defaults synchronize];

}

-(ibaction) Read {

Nsuserdefaults *defaults = [Nsuserdefaults standarduserdefaults];

NSString *account = [Defaults objectforkey:@ "Account"];

BOOL autologin = [Defaults boolforkey:@ "Auto_login"];

NSLog (@ "%@-%d", account, Autologin);

}

Nskeyedarchiver Model method

Generic object that stores model objects, cannot store generic objects (dictionaries, strings, arrays, etc.)

Create a new 2 model

The model has the corresponding data

Mjstudent

#import <Foundation/Foundation.h>

@interface Mjstudent:nsobject <NSCoding>//compliance with nscoding Agreement

@property (nonatomic, copy) NSString *no;

@property (nonatomic, assign) double height;

@property (nonatomic, assign) int age;

In the. m file

@interface Mjstudent ()

@end

@implementation Mjstudent

/** Important

* When an object is written to a file, it is called

* In this method, clarify which attributes need to be stored

*/

If you do not write the encoding method, the system crashes directly

This is the encoding method of preserving the data.

-(void) Encodewithcoder: (Nscoder *) encoder

{

[Encoder encodeObject:self.no forkey:@ "no"];

[Encoder encodeInt:self.age forkey:@ "age"];

[Encoder encodeDouble:self.height forkey:@ "height"];

}

/** Important

* Called when parsing an object from a file

* In this method, clarify which attributes need to be stored

*/

This is the way to parse the data.

-(ID) Initwithcoder: (Nscoder *) decoder

{

if (self = [super init]) {

Read the contents of a file

self.no = [Decoder decodeobjectforkey:@ "no"];

Self.age = [Decoder decodeintforkey:@ "age"];

Self.height = [Decoder decodedoubleforkey:@ "height"];

}

return self;

}

Inside the Viewcontroller.

Save Data button

-(ibaction) Save {

1. New Model objects

Mjstudent *stu = [[Mjstudent alloc] init];

stu.no = @ "42343254";

Stu.age = 20;

Stu.height = 1.55;

2. Archiving Model objects

2.1. Get the full path of documents

NSString *doc = [Nssearchpathfordirectoriesindomains (nsdocumentdirectory, Nsuserdomainmask, YES) lastObject];

2.2. Get the full path of the file

NSString *path = [Doc stringbyappendingpathcomponent:@ "Stu.data"];

2.3. Archive an Object

[Nskeyedarchiver Archiverootobject:stu Tofile:path];

}

Read Data button

-(ibaction) Read {

1. Get the full path of documents

NSString *doc = [Nssearchpathfordirectoriesindomains (nsdocumentdirectory, Nsuserdomainmask, YES) lastObject];

2. Get the full path of the file

NSString *path = [Doc stringbyappendingpathcomponent:@ "Stu.data"];

3. Read the Mjstudent object from the file

Mjstudent *stu = [Nskeyedunarchiver Unarchiveobjectwithfile:path];

NSLog (@ "%@%d%f", stu.no, Stu.age, stu.height);

}

Three kinds of data storage (Plist,nsuserdefaults storage, Nskeyedarchiver model method)