iOS archive, solution files

In iOS, an instance object is stored in a sandbox, called an archive, and an instance object is read from a sandbox file called a solution file.

A chestnut is about to be born: for example, you want to deposit the value of the name and age attribute in a Zhhperson class into a sandbox file and read it in a sandbox file when needed.

Analysis:

In order to archive the object of the person class, the operation of the file must be implemented in two ways: Encodewithcoder: The system executes automatically when the file is archived, Initwithcoder: The system executes automatically when the document is unpacked.

For the implementation of the two methods, here is the use of the High: the runtime mechanism. This chestnut does not see the benefits of the runtime mechanism. But, but, finally, no, but.

ZHHPerson.h

#import <Foundation/Foundation.h>

@interface Person:nsobject

@property (nonatomic, copy) nsstring* name;

@property (nonatomic, assign) int age;

@end

Zhhperson.m

#import "ZHHPerson.h"

#import <objc/runtime.h>

@implementation Zhhperson

Solution file

-(ID) Initwithcoder: (Nscoder *) Decoder {

if (self = [super init]) {

U_int count;

Get all member variables of this class

ivar* Ivars = Class_copyivarlist ([self class], &count);

for (U_int i=0; i<count; i++) {

Remove the member variable of the corresponding position

Ivar Ivar = ivars[i];

Const char* KeyChar = Ivar_getname (Ivar);

Solution file

nsstring* keystr = [NSString Stringwithutf8string:keychar];

[Self Setvalue:[decoder decodeobjectforkey:keystr] forkey:keystr];

}

Free (ivars);

}

return self;

}

Archive

-(void) Encodewithcoder: (Nscoder *) encoder

{

unsigned int count = 0;

Get all member variables of this class

Ivar *ivars = Class_copyivarlist ([self class], &count);

Iterate through all the member variables

for (int i = 0; i<count; i++) {

Remove the member variable of the corresponding position

Ivar Ivar = ivars[i];

View member variables

const char *keychar = Ivar_getname (Ivar);

Archive

NSString *keystr = [NSString Stringwithutf8string:keychar];

[Encoder encodeobject:[self VALUEFORKEY:KEYSTR] forkey:keystr];

}

Release

Free (ivars);

}

Rewrite

-(nsstring*) Description {

return [NSString stringwithformat:@ "name =%@, age =%d", Self.name, Self.age];

}

@end

The Zhhperson class is okle.

Now you can use this class to do the file, archive the operation.

Archive:

zhhperson* p = [[Person alloc] init];

P.name = @ "Zhh";

P.age = 25;

[Nskeyedarchiver archiverootobject:p Tofile:path];

Solution file:

zhhperson* p = [Nskeyedunarchiver Unarchiveobjectwithfile:path];

NSLog (@ "%@", p);

iOS archive, solution files