Ios-archiver file Archive (2)

Archiver is a way of persisting data, and the difference between him and plist is that he can persist his own definition of objects. But he is not plist so convenient.

Archiver data persisted by default is Nsnumber,nsarray,nsdictionary,nsstring,nsdata, because these objects have been implemented

<NSCoding> agreement. If we want to implement the archiver persistence of an object, we must also implement the object.

1.<NSCoding> protocol mainly for archiving/recovery of files two methods

Recover archive File As Object-(ID) Initwithcoder: (Nscoder *) adecoder//archive, make object persistent-(void) Encodewithcoder: (Nscoder *) Acoder

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For example, the following. We first get the path to the archive file

#pragma mark gets the file path-(NSString *) filepath{    Nsarray *dirpaths=nssearchpathfordirectoriesindomains ( NSDocumentDirectory, Nsalldomainsmask, YES);    NSString *dirpath=dirpaths[0];    NSString *filepath=[dirpath stringbyappendingpathcomponent:@ "Aa.archiver"];    return FilePath;}

2. How the system default objects are archived (nsnumber,nsarray,nsdictionary, Nsstring,nsdata)

#pragma mark archive/Restore Array object-(void) savearray{        nsstring *filepath=[self filepath];////    nsarray *[email protected ][@ "TTT", @ "BBB", @25];//    [nskeyedarchiver archiverootobject:arr tofile:filepath];//    nsarray *arr1=[ Nskeyedunarchiver Unarchiveobjectwithfile:filepath];    NSLog (@ "%@", arr1);}

#pragma mark archive/Restore Dictionary objects-(void) savedic{    nsstring *filepath=[self filepath];//nsdictionary *[email    protected]{@ "name": @ "lean" @ "age": @25};//    BOOL flag=[nskeyedarchiver archiverootobject:dict Tofile:filepath] ;//    NSLog (@ "%d", flag);    Nsdictionary *dict2=[nskeyedunarchiver Unarchiveobjectwithfile:filepath];    NSLog (@ "%@", Dict2);}

3. How to archive your own definition object.

Defines a person class. For example, the following:

#import <Foundation/Foundation.h> @interface person:nsobject <NSCoding> @property (nonatomic,copy) NSString *name; @property (nonatomic,assign) int age;+ (person *) Initwithname: (NSString *) name Andage: (int.) age; @end # Import "Person.h" @implementation person+ (Person *) Initwithname: (NSString *) name Andage: (int.) age{person    *p=[[ Person Alloc] init];    P.name=name;    P.age=age;    return p;} -(void) Encodewithcoder: (Nscoder *) acoder{    [acoder encodeObject:self.name forkey:@ "name"];    [Acoder encodeInt:self.age forkey:@ "Age"];} -(ID) Initwithcoder: (Nscoder *) adecoder{    [self setname:[adecoder decodeobjectforkey:@ "name"]];    [Self setage:[adecoder decodeintforkey:@ ' age '];    return self;} @end

TIP: Both encode and Decode are based on the type of object used to choose different methods. As

EncodeInt:forkey:encodeDouble:forkey:encodeFloat:forkey:

DecodeObjectForKey:decodeIntForKey:decodeDoubleForKey:

Nskeyedarchiver Archiverootobject:tofile:

Nskeyedunarchiver Unarchiveobjectwithfile:

Each is on the need to file.

Two classes to manipulate the recovered objects

Once you have defined the person class, call the following for example where you need to archive:

#pragma mark archives/restores its own definition object-(void) saveperson{    nsstring *filepath=[self FilePath];    Person *p=[person initwithname:@ "lean" andage:22];    BOOL flag=[nskeyedarchiver archiverootobject:p Tofile:filepath];    Person *p2=[nskeyedunarchiver Unarchiveobjectwithfile:filepath];    NSLog (@ "%d-%d", Flag,p2.age);}

for its person class, if the class also has its own definition object as a property. Same implementation <NSCoding> Protocol

4. If the object is a subclass of an object, here we create a subclass called the student class as the person

#import "Person.h" @interface student:person@property (nonatomic, assign) int no;+ (Student *) Initwithname: (NSString *) n Ame andage: (int) Age Andno: (int) No; @end

The same student also need to implement the Nscoding protocol method

-(ID) Initwithcoder: (Nscoder *) adecoder{    if (self=[super Initwithcoder:adecoder]) {        [self setno:[adecoder decodeintforkey:@ "No"];    }    return self;} -(void) Encodewithcoder: (Nscoder *) acoder{    [Super Encodewithcoder:acoder];    [Acoder encodeInt:self.no forkey:@ "No"];}

#pragma mark archives/restores its own subclass object-(void) savestudent{    nsstring *filepath=[self FilePath];    Student *p=[student initwithname:@ "lean" andage:22 andno:150133];    BOOL flag=[nskeyedarchiver archiverootobject:p Tofile:filepath];    Student *p2=[nskeyedunarchiver Unarchiveobjectwithfile:filepath];    NSLog (@ "%d-%@", Flag,p2.name);}

Ios-archiver file Archive (2)