第十二章、objective-c归档

第十二章、归档,内容概要,使用XML属性列表进行归档使用NSKeyedArchiver归档编码方法和解码方法使用NSData创建自定义档案使用归档程序复制对象,使用XML属性列表进行归档,归档的概念：用某种格式来保存一个或多个对象，以便以后还原这些对象的过程。通过这个过程包括将（多个）对象写入文件，以便以后读回该对象归档的方式：属性列表和带键值的编码,使用XML属性列表进行归档,XML属性列表的内容：默认参数选择、应用程序设置和配置信息等采用属性列表进行归档存储的信息是有限的，因为并没有保存对象所属的类信息，没有存储对象的多个引用，也没有保持对象的可变性属性列表归档只针对于Foundation对象,使用XML属性列表进行归档,写入文件：对于Foundation的类，你可以使用在这些类中实现的writeToFile:atomically：方法将数据写到文件中,使用XML属性列表进行归档,/Program19.1#import#import#import#importintmain(intargc,char*argv)NSAutoreleasePool*pool=NSAutoreleasePoolallocinit;NSDictionary*glossary=NSDictionarydictionaryWithObjectsAndKeys:Aclassdefinedsootherclassescaninheritfromit.,abstractclass,Toimplementallthemethodsdefinedinaprotocol,adopt,Storinganobjectforlateruse.,archiving,nil;,使用XML属性列表进行归档,if(glossarywriteToFile:glossaryatomically:YES=NO)NSLog(Savetofilefailed!);pooldrain;return0;,希望首先将字典写入临时备份文件中，写入成功后，将把最终数据转移到名为glossary的指定文件中。这项安全措施可使得文件在执行操作的过程中崩溃时免受破坏。,使用XML属性列表进行归档,glossary文件的内容如下：,/*IfyouexaminethecontentsoftheglossaryfilecreatedbyProgram19.1,itlookslikethis:*/abstractclass/属性列表Aclassdefinedsootherclassescaninheritfromit.adoptToimplementallthemethodsdefinedinaprotocolarchivingStoringanobjectforlateruse.,使用XML属性列表进行归档,【注意】根据字典创建属性列表时，字典中的键必须全是NSString对象。字典中的值可以是NSString、NSArray、NSDictionary、NSData、NSNumber对象,使用XML属性列表进行归档,从文件中读取：dictionaryWithContentOfFile:arrayWithContentOfFile:stringWithContentOfFile:dataWithContentsOfFile:.,使用XML属性列表进行归档,/Program19.2#import#import#import#import#importintmain(intargc,char*argv)NSAutoreleasePool*pool=NSAutoreleasePoolallocinit;NSDictionary*glossary;glossary=NSDictionarydictionaryWithContentsOfFile:glossary;for(NSString*keyinglossary)NSLog(%:%,key,glossaryobjectForKey:key);pooldrain;return0;,使用XML属性列表进行归档,【注意】属性列表文件不必一定由程序创建，可以来自文本编辑器，或/Developer/Applications/Utilities下的PropertyListEditor,Program19.2Output:archiving:Storinganobjectforlateruse.abstractclass:Aclassdefinedsootherclassescaninheritfromit.adopt:Toimplementallthemethodsdefinedinaprotocol,内容概要,使用XML属性列表进行归档使用NSKeyedArchiver归档编码方法和解码方法使用NSData创建自定义档案使用归档程序复制对象,使用NSKeyedArchiver归档,属性列表归档只针对Foundation类。要想将各种类型的对象存储到文件中，可以采用NSKeyedArchiver归档头文件：,使用NSKeyedArchiver归档(cont.),【注意】1、MacOXX从版本10.2开始支持带键的档案。在此之前，要使用NSArchiver类创建连续的归档。连续的归档需要完全按照写入时的顺序读取归档中的数据2、在带键的档案中，每个归档字段都有一个名称。归档某个对象时，会为它提供一个键。从归档中检索该对象时，需根据键来检索这样可以按照任意的顺序将对象写入归档并进行检索。4、iPhoneSDK中没有提供NSArchiver。如果想在iPhone上使用归档功能，则必须使用NSKeyedArchiver,使用NSKeyedArchiver归档(cont.),写入文件：archiveRootObject:toFile:方法将对象存储到磁盘上。,使用NSKeyedArchiver归档(cont.),/DEMO19-3#import#import#import#import#importintmain(intargc,char*argv)NSAutoreleasePool*pool=NSAutoreleasePoolallocinit;NSDictionary*glossary=NSDictionarydictionaryWithObjectsAndKeys:Aclassdefinedsootherclassescaninheritfromit,abstractclass,Toimplementallthemethodsdefinedinaprotocol,adopt,使用NSKeyedArchiver归档(cont.),Storinganobjectforlateruse,archiving,nil;NSKeyedArchiverarchiveRootObject:glossarytoFile:glossary.archive;poolrelease;return0;,使用NSKeyedArchiver归(cont.),从文件读取：通过NSKeyedUnarchiver的unArchiverObjectWithFile:方法将创建的归档文件读入执行程序中,使用NSKeyedArchiver归档(cont.),/Program19.4#import#import#import#import#import#importintmain(intargc,char*argv)NSAutoreleasePool*pool=NSAutoreleasePoolallocinit;NSDictionary*glossary;glossary=NSKeyedUnarchiverunarchiveObjectWithFile:glossary.archive;for(NSString*keyinglossary)NSLog(%:%,key,glossaryobjectForKey:key);pooldrain;return0;,使用NSKeyedArchiver归档(cont.),Program19.4Output:abstractclass:Aclassdefinedsootherclassescaninheritfromit.adopt:Toimplementallthemethodsdefinedinaprotocolarchiving:Storinganobjectforlateruse.,内容概要,使用XML属性列表进行归档使用NSKeyedArchiver归档编码方法和解码方法使用NSData创建自定义档案使用归档程序复制对象,编码方法和解码方法,可以使用以上的方法归档和恢复NSStrng、NSArray、NSDictionary、NSSet等基本的Objective-C类对象通常自定义的类不能直接归档，比如归档AddressBook，若对其归档则会出现如下的错误提示,*-AddressBookencodeWithCoder:selectornotrecognized*Uncaughtexception:*-AddressBookencodeWithCoder:selectornotrecognized,编码方法和解码方法:(cont.),若要归档必须使该类遵守协议，在该类中添加encodeWithCoder：方法和initWithCoder：方法以实现归档对象和恢复对象编码方法一般应指定如何归档想要保存的对象中的每个实例变量。,编码方法和解码方法:(cont.),下面列出带键的归档中编码和解码的方法对于基本的Objective-C类，可以使用encodeObject:forKey:和decodeObjectforKey:编码和解码,Table19.1EncodingandDecodingBasicDataTypesinKeyedArchivesEncoderDecoderencodeBool:forKey:decodeBoolforKey:encodeInt:forKey:decodeIntforKey:encodeInt32:forKey:decodeInt32forKey:encodeInt64:forKey:decodeInt64forKey:encodeFloat:forKey:decodeFloatforKey:encodeDouble:forKey:decodeDoubleforKey:,编码方法和解码方法:(cont.),/基本的Objective-C类编码和解码示例：/Program19_6Addresscard.hInterfaceFile#importinterfaceAddressCard:NSObjectNSString*name;NSString*email;property(nonatomic,copy)NSString*name,*email;-(void)setName:(NSString*)theNameandEmail:(NSString*)theEmail;-(void)retainName:(NSString*)theNameandEmail:(NSString*)theEmail;-(NSComparisonResult)compareNames:(id)element;-(void)print;end,编码方法和解码方法:(cont.),#importAddressCard.himplementationAddressCardsynthesizename,email;-(void)setName:(NSString*)theNameandEmail:(NSString*)theEmailselfsetName:theName;selfsetEmail:theEmail;/Comparethetwonamesfromthespecifiedaddresscards-(NSComparisonResult)compareNames:(id)elementreturnnamecompare:elementname;,编码方法和解码方法:(cont.),-(void)printNSLog(=);NSLog(|);NSLog(|%-31s|,nameUTF8String);NSLog(|%-31s|,emailUTF8String);NSLog(|);NSLog(|);NSLog(|);NSLog(|OO|);NSLog(=);-(AddressCard*)copyWithZone:(NSZone*)zoneAddressCard*newCard=AddressCardallocWithZone:zoneinit;newCardretainName:nameandEmail:email;returnnewCard;,编码方法和解码方法:(cont.),-(void)retainName:(NSString*)theNameandEmail:(NSString*)theEmailname=theNameretain;email=theEmailretain;-(void)encodeWithCoder:(NSCoder*)encoderencoderencodeObject:nameforKey:AddressCardName;encoderencodeObject:emailforKey:AddressCardEmail;-(id)initWithCoder:(NSCoder*)decodername=decoderdecodeObjectForKey:AddressCardNameretain;email=decoderdecodeObjectForKey:AddressCardEmailretain;returnself;,编码方法和解码方法:(cont.),-(void)deallocnamerelease;emailrelease;superdealloc;end,编码方法和解码方法:(cont.),#importAddressCard.hinterfaceAddressBook:NSObjectNSString*bookName;NSMutableArray*book;property(nonatomic,copy)NSString*bookName;property(nonatomic,copy)NSMutableArray*book;-(id)initWithName:(NSString*)name;-(void)sort;-(void)addCard:(AddressCard*)theCard;-(void)removeCard:(AddressCard*)theCard;-(int)entries;-(void)list;-(AddressCard*)lookup:(NSString*)theName;-(void)dealloc;end,编码方法和解码方法:(cont.),#importAddressBook.himplementationAddressBooksynthesizebook,bookName;/setuptheAddressBooksnameandanemptybook-(id)initWithName:(NSString*)nameself=superinit;if(self)bookName=NSStringallocinitWithString:name;book=NSMutableArrayallocinit;returnself;-(void)sortbooksortUsingSelector:selector(compareNames:);,编码方法和解码方法:(cont.),-(void)addCard:(AddressCard*)theCardbookaddObject:theCard;-(void)removeCard:(AddressCard*)theCardbookremoveObjectIdenticalTo:theCard;-(int)entriesreturnbookcount;,编码方法和解码方法:(cont.),-(void)listNSLog(=Contentsof:%=,bookName);for(AddressCard*theCardinbook)NSLog(%-20s%-32s,theCUTF8String,theCard.emailUTF8String);NSLog(=);/lookupaddresscardbynameassumesanexactmatch-(AddressCard*)lookup:(NSString*)theNamefor(AddressCard*nextCardinbook)if(nextCardnamecaseInsensitiveCompare:theName=NSOrderedSame)returnnextCard;returnnil;,编码方法和解码方法:(cont.),-(void)deallocbookNamerelease;bookrelease;superdealloc;-(void)encodeWithCoder:(NSCoder*)encoderencoderencodeObject:bookNameforKey:AddressBookBookName;encoderencodeObject:bookforKey:AddressBookBook;-(id)initWithCoder:(NSCoder*)decoderbookName=decoderdecodeObjectForKey:AddressBookBookNameretain;book=decoderdecodeObjectForKey:AddressBookBookretain;returnself;,编码方法和解码方法:(cont.),/MethodforNSCopyingprotocol-(id)copyWithZone:(NSZone*)zoneAddressBook*newBook=selfclassallocWithZone:zone;newBookinitWithName:bookName;newBooksetBook:book;returnnewBook;end,编码方法和解码方法:(cont.),#importAddressBook.h#importintmain(intargc,char*argv)NSString*aName=JuliaKochan;NSString*aEmail=jewls337;NSString*bName=TonyIannino;NSString*bEmail=tony.iannino;NSString*cName=StephenKochan;NSString*cEmail=stevesteve_;NSString*dName=JamieBaker;NSString*dEmail=jbaker;NSAutoreleasePool*pool=NSAutoreleasePoolallocinit;AddressCard*card1=AddressCardallocinit;AddressCard*card2=AddressCardallocinit;AddressCard*card3=AddressCardallocinit;AddressCard*card4=AddressCardallocinit;AddressBook*myBook=AddressBookalloc;,编码方法和解码方法:(cont.),/Firstsetupfouraddresscardscard1setName:aNameandEmail:aEmail;card2setName:bNameandEmail:bEmail;card3setName:cNameandEmail:cEmail;card4setName:dNameandEmail:dEmail;myBook=myBookinitWithName:StevesAddressBook;/AddsomecardstotheaddressbookmyBookaddCard:card1;myBookaddCard:card2;myBookaddCard:card3;myBookaddCard:card4;myBooksort;,编码方法和解码方法:(cont.),if(NSKeyedArchiverarchiveRootObject:myBooktoFile:addrbook.arch=NO)NSLog(archivingfailed);card1release;card2release;card3release;card4release;myBookrelease;pooldrain;return0;,编码方法和解码方法:(cont.),/Program19.7Addresscard.hInterfaceFile对AddressBook解码#importAddressBook.h#importintmain(intargc,char*argv)AddressBook*myBook;NSAutoreleasePool*pool=NSAutoreleasePoolallocinit;myBook=NSKeyedUnarchiverunarchiveObjectWithFile:addrbook.arch;myBooklist;pooldrain;return0;,Program19.7Output=Contentsof:StevesAddressBook=JamieBakerjbakerJuliaKochanjewls337StephenKochanstevesteve_TonyIanninotony.iannino=,编码方法和解码方法:(cont.),/DEMO19_8对内置类行数据编码示例interfaceFoo:NSObjectNSString*strVal;intintVal;floatfloatVal;property(copy,nonatomic)NSString*strVal;propertyintintVal;propertyfloatfloatVal;end,编码方法和解码方法:(cont.),implementationFoosynthesizestrVal,intVal,floatVal;-(void)encodeWithCoder:(NSCoder*)encoder/对每个实例变量编码encoderencodeObject:strValforKey:”FoostrVal”;encoderencodeInt:intValforKey:”FoointVal”;encoderencodeFloat:floatValforKey:”FoofloatVal”;-(id)initWithCoder:(NSCoder*)decoder/解码每个实例变量strVal=decoderdecodeObjectForKey:”FoostrVal”retain;intVal=decoderdecodeIntForKey:”FoointVal”;floatVal=decoderdecodeFloatForKey:”FoofloatVal”;returnself;end,编码方法和解码方法:(cont.),#import#import#import#import#import“Foo.h”/DefinitionforourFooclassintmain(intargc,char*argv)NSAutoreleasePool*pool=NSAutoreleasePoolallocinit;Foo*myFoo1=Fooallocinit;Foo*myFoo2;myFoo1setStrVal:”Thisisthestring”;myFoo1setIntVal:12345;myFoo1setFloatVal:98.6;NSKeyedArchiverarchiveRootObject:myFoo1toFile:”foo.arch”;myFoo2=NSKeyedUnarchiverunarchiveObjectWithFile:”foo.arch”;NSLog(”%n%in%g”,myFoo2strVal,myFoo2intVal,myFoo2floatVal);myFoo1release;pooldrain;return0;,Program19.8Output:Thisisthestring1234598.6,内容概要,使用XML属性列表进行归档使用NSKeyedArchiver归档编码方法和解码方法使用NSData创建自定义档案使用归档程序复制对象,使用NSData创建自定义档案,有时可能不希望使用archiveRootObject:ToFile:方法将对象直接写入文件，而是临时放到有NSData对象创建的临时存储空间中保存NSData对象用来保存一块内存空间作为临时存储数据的空间dataArea1=NSMutableDatadata;dataArea2=NSDatadata;,使用NSData创建自定义档案:(cont.),/Program19_9编码#import#import#import#import#import#import#importAddressBook.h#importFoo.hintmain(intargc,char*argv)NSAutoreleasePool*pool=NSAutoreleasePoolallocinit;Foo*myFoo1=Fooallocinit;Foo*myFoo2;NSMutableData*dataArea;NSKeyedArchiver*archiver;AddressBook*myBook;,使用NSData创建自定义档案:(cont.),/InsertcodefromProgram19.7tocreateanAddressBook/inmyBookcontainingfouraddresscardsmyFoo1setStrVal:Thisisthestring;myFoo1setIntVal:12345;myFoo1setFloatVal:98.6;/SetupadataareaandconnectittoanNSKeyedArchiverobjectdataArea=NSMutableDatadata;archiver=NSKeyedArchiverallocinitForWritingWithMutableData:dataArea;/NowwecanbegintoarchiveobjectsarchiverencodeObject:myBookforKey:myaddrbook;archiverencodeObject:myFoo1forKey:myfoo1;archiverfinishEncoding;/Writethearchiveddatatoafileif(dataAreawriteToFile:myArchiveatomically:YES=NO)NSLog(Archivingfailed!);,使用NSData创建自定义档案:(cont.),archiverrelease;myFoo1release;pooldrain;return0;,使用NSData创建自定义档案:(cont.),/Program19_10解码#import#import#import#import#import#import#importAddressBook.h#importFoo.hintmain(intargc,char*argv)NSAutoreleasePool*pool=NSAutoreleasePoolallocinit;NSData*dataArea;NSKeyedUnarchiver*unarchiver;Foo*myFoo1;AddressBook*myBook;/Readinthearchiveandconnectan/NSKeyedUnarchiverobjecttoitdataArea=NSDatadataWithContentsOfFile:myArchive;,使用NSData创建自定义档案:(cont.),if(!dataArea)NSLog(Cantreadbackarchivefile!);return(1);unarchiver=NSKeyedUnarchiverallocinitForReadingWithData:dataArea;/DecodetheobjectswepreviouslystoredinthearchivemyBook=unarchiverdecodeObjectForKey:myaddrbook;myFoo1=unarchiverdecodeObjectForKey:myfoo1;unarchiverfin