Explanation of Objective-C archiving Problem Solving

Objective-C ArchiveThe problem is solved in this article, which focuses on learning how to use Objective-C.Archive, This article solves this problem in detail, let's look at the details.

For basic Objective-C class objects (NSString, NSArray ...):

Method 1: Use the XML Attribute list for archiving.

Code

 
 

  
  
NSDictionary * glossay;
  
  
// Save
  
  
Glossay = [NSDictionary dictionaryWithObjectsAndKeys: @ "obj val 1", @ "key1", @ "obj val 2", @ "key2", nil];
  
  
If ([glossay writeToFile: @ "glossary" atomically: YES] = NO ){
  
  
NSLog (@ "Save to file failed! ");
  
  
}
  
  
// Obtain
  
  
Glossay = [NSDictionary dictionaryWithContentsOfFile: @ "glossary"];
  
  
NSLog (@ "% @", [glossay valueForKey: @ "key2"]);
 
 

Method 2: Use NSKeyedArchiver for archiving.

Code

 
 

  
  
NSDictionary * glossay;
  
  
Glossay = [NSDictionary dictionaryWithObjectsAndKeys: @ "obj val 1", @ "key1", @ "obj val 2", @ "key2", nil];
  
  
// Save
  
  
If ([NSKeyedArchiver archiveRootObject: glossay toFile: @ "glossay. archiver"] = NO ){
  
  
NSLog (@ "write file fail !! ");
  
  
}
  
  
// Obtain
  
  
Glossay = [NSKeyedUnarchiver unarchiveObjectWithFile: @ "glossay. archiver"];
  
  
NSLog (@ "% @", [glossay valueForKey: @ "key2"]);
 
 

For a custom Class, you need to implement the NSCoding protocol, and then use the above method 2 for archiving:

Code

 
 

  
  
// TestProperty. h
  
  
# Import <Cocoa/Cocoa. h>
  
  
@ Interface TestProperty: NSObject <NSCopying, NSCoding> {
  
  
NSString * name;
  
  
NSString * password;
  
  
NSMutableString * interest;
  
  
NSInteger myInt;
  
  
}
  
  
12 @ property (retain, nonatomic) NSString * name, * password;
  
  
@ Property (retain, nonatomic) NSMutableString * interest;
  
  
@ Property NSInteger myInt;
  
  
-(Void) rename :( NSString *) newname;
  
  
@ End
  
  
================================
  
  
// TestProperty. m
  
  
23 # import "TestProperty. h"
  
  
25 26 @ implementation TestProperty
  
  
28 @ synthesize name, password, interest;
  
  
@ Synthesize myInt;
  
  
-(Void) rename :( NSString *) newname {
  
  
// You can directly write it here
  
  
// Self. name = newname;
  
  
//
  
  
If (name! = Newname ){
  
  
[Name autorelease];
  
  
Name = newname;
  
  
[Name retain];
  
  
}
  
  
}
  
  
-(Void) dealloc {
  
  
Self. name = nil;
  
  
Self. password = nil;
  
  
Self. interest = nil;
  
  
[Super dealloc];
  
  
}
  
  
-(Id) copyWithZone :( NSZone *) zone {
  
  
TestProperty * newObj = [[self class] allocWithZone: zone] init];
  
  
NewObj. name = name;
  
  
NewObj. password = password;
  
  
NewObj. myInt = myInt;
  
  
// Deep copy
  
  
NSMutableString * tmpStr = [interest mutableCopy];
  
  
NewObj. interest = tmpStr;
  
  
[TmpStr release];
  
  
// Light copy
  
  
// NewObj. interest = interest;
  
  
Return newObj;
  
  
}
  
  
-(Void) encodeWithCoder :( NSCoder *) ACO {
  
  
// If it is a subclass, add:
  
  
// [Super encodeWithCoder: ACO];
  
  
// Note that the NSCoding class is actually used to process objects )!
  
  
[Ecoder encodeObject: name forKey: @ "TestPropertyName"];
  
  
[Ecoder encodeObject: password forKey: @ "TestPropertyPassword"];
  
  
[Ecoder encodeObject: interest forKey: @ "TestPropertyInterest"];
  
  
// Note how to handle the basic type here!
  
  
[Ecoder encodeInt: myInt forKey: @ "TestPropertyMyInt"];
  
  
}
  
  
-(Id) initWithCoder :( NSCoder *) aDecoder {
  
  
// If it is a subclass, add:
  
  
// Self = [super initWithCoder: aDecoder];
  
  
// Decode the object
  
  
Name = [[aDecoder decodeObjectForKey: @ "TestPropertyName"] retain];
  
  
Password = [[aDecoder decodeObjectForKey: @ "TestPropertyPassword"] retain];
  
  
Interest = [[aDecoder decodeObjectForKey: @ "TestPropertyInterest"] retain];
  
  
// Basic decoding type
  
  
MyInt = [aDecoder decodeIntForKey: @ "TestPropertyMyInt"];
  
  
Return self;
  
  
}
  
  
@ End
  
  
====================
  
  
// Test
  
  
// Save
  
  
TestProperty * test = [[TestProperty alloc] init];
  
  
Test. name = @ "pxl ";
  
  
Test. password = @ "pwd ...";
  
  
Test. interest = [NSMutableString stringWithString: @ "interest..."];
  
  
Test. myInt = 123;
  
  
If ([NSKeyedArchiver archiveRootObject: test toFile: @ "testproerty. archive"] = NO ){
  
  
NSLog (@ "write to file fail !! ");
  
  
}
  
  
// Obtain
  
  
TestProperty * test = [NSKeyedUnarchiver unarchiveObjectWithFile: @ "testproerty. archive"];
  
  
NSLog (@ "% @", test. name );
 
 

Use NSData to create a definition file.

The preceding TestProperty class that has implemented the NSCoding protocol is used as an example. The Code

 
 

  
  
// Save
  
  
TestProperty * test = [[TestProperty alloc] init];
  
  
Test. name = @ "pxl ";
  
  
Test. password = @ "pwd ...";
  
  
Test. interest = [NSMutableString stringWithString: @ "interest..."];
  
  
Test. myInt = 123;
  
  
NSMutableData * dataArea = [NSMutableData data];
  
  
NSKeyedArchiver * archiver = [[NSKeyedArchiver alloc] initForWritingWithMutableData: dataArea];
  
  
[Archiver encodeObject: test forKey: @ "testObj"];
  
  
// You can add another object 13 //......
  
  
[Archiver finishEncoding];
  
  
If ([dataArea writeToFile: @ "test. archiver" atomically: YES] = NO ){
  
  
NSLog (@ "write to file fail ...");
  
  
}
  
  
[Archiver release];
  
  
[Test release];
  
  
================
  
  
// Obtain
  
  
NSData * dataArea = [NSData dataWithContentsOfFile: @ "test. archiver"];
  
  
If (! DataArea ){
  
  
NSLog (@ "Can't read back archive file ");
  
  
Return (1 );
  
  
}
  
  
NSKeyedUnarchiver * unarchiver = [[NSKeyedUnarchiver alloc] initForReadingWithData: dataArea];
  
  
TestProperty * test = [unarchiver decodeObjectForKey: @ "testObj"];
  
  
[Unarchiver finishDecoding];
  
  
NSLog (@ "% @", test. name );
  
  
[Unarchiver release];
 
 

Object deep Replication Using archive:

Code

 
 

  
  
// Delete the NSCopying protocol Code implemented in the TestProperty class first.
  
  
TestProperty * test = [[TestProperty alloc] init];
  
  
Test. name = @ "pxl ";
  
  
Est. password = @ "pwd ...";
  
  
Test. interest = [NSMutableString stringWithString: @ "interest..."];
  
  
Test. myInt = 123;
  
  
// Perform a deep copy of test 10 NSData * data = [NSKeyedArchiver archivedDataWithRootObject: test]; 11
  
  
TestProperty * test2 = [NSKeyedUnarchiver unarchiveObjectWithData: data];
  
  
[Test2.interest appendString: @ "film"];
  
  
NSLog (@ "% @", test. interest); 15 NSLog (@ "% @", test2.interest );
  
  
// Output
  
  
16:11:47. 391 HelloWorld [4599: a0f] interest...
  
  
16:11:47. 393 HelloWorld [4599: a0f] interest... film
 
 

Summary: DetailsObjective-C ArchiveAfter the problem is solved, I hope this article will help you!