归档指的是另一种型式的序列化，但它是任保对象都可以实现的更常规的类型。
其作用为：进行数据的持久化保存。
对象必须实现NSCodeing协议和NSCopying协议。
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@interface FourLines : NSObject <NSCoding, NSCopying> { NSString *field1; NSString *field2; NSString *field3; NSString *field4; } @property (nonatomic, retain) NSString *field1; @property (nonatomic, retain) NSString *field2; @property (nonatomic, retain) NSString *field3; @property (nonatomic, retain) NSString *field4; @end - (void)encodeWithCoder:(NSCoder *)encoder { [encoder encodeObject:field1 forKey:kField1Key]; [encoder encodeObject:field2 forKey:kField2Key]; [encoder encodeObject:field3 forKey:kField3Key]; [encoder encodeObject:field4 forKey:kField4Key]; } - (id)initWithCoder:(NSCoder *)decoder { if (self = [super init]) { self.field1 = [decoder decodeObjectForKey:kField1Key]; self.field2 = [decoder decodeObjectForKey:kField2Key]; self.field3 = [decoder decodeObjectForKey:kField3Key]; self.field4 = [decoder decodeObjectForKey:kField4Key]; } return self; } - (id)copyWithZone:(NSZone *)zone { FourLines *copy = [[[self class] allocWithZone: zone] init]; copy.field1 = [[self.field1 copyWithZone:zone] autorelease]; copy.field2 = [[self.field2 copyWithZone:zone] autorelease]; copy.field3 = [[self.field3 copyWithZone:zone] autorelease]; copy.field4 = [[self.field4 copyWithZone:zone] autorelease];
return copy; }
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获取归档文件
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- (NSString *)dataFilePath { NSArray *paths = NSSearchPathForDirectoriesInDomains( NSDocumentDirectory, NSUserDomainMask, YES); NSString *documentsDirectory = [paths objectAtIndex:0]; return [documentsDirectory stringByAppendingPathComponent:@"archive"]; } |
对数据进行归档
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FourLines *fourLines = [[FourLines alloc] init]; fourLines.field1 = field1.text; fourLines.field2 = field2.text; fourLines.field3 = field3.text; fourLines.field4 = field4.text;
//对数据进行归档 NSMutableData *data = [[NSMutableData alloc] init]; NSKeyedArchiver *archiver = [[NSKeyedArchiver alloc] initForWritingWithMutableData:data]; [archiver encodeObject:fourLines forKey:@"Data"]; [archiver finishEncoding]; [data writeToFile:[self dataFilePath] atomically:YES]; [fourLines release]; [archiver release]; [data release];
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获取归档数据
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NSString *filePath = [self dataFilePath]; if ([[NSFileManager defaultManager] fileExistsAtPath:filePath]) { NSData *data = [[NSMutableData alloc] initWithContentsOfFile:[self dataFilePath]]; NSKeyedUnarchiver *unarchiver = [[NSKeyedUnarchiver alloc] initForReadingWithData:data]; FourLines *fourLines = [unarchiver decodeObjectForKey:@"Data"]; [unarchiver finishDecoding];
field1.text = fourLines.field1; field2.text = fourLines.field2; field3.text = fourLines.field3; field4.text = fourLines.field4;
[unarchiver release]; [data release]; } |
原文地址：http://www.cnblogs.com/AbelChen1991/p/3730808.html
