iPhone應(yīng)用開發(fā)之模型對(duì)象歸檔是本文要介紹的內(nèi)容，主要是來介紹歸檔，它指的是另一種型式的序列化，但它是任保對(duì)象都可以實(shí)現(xiàn)的更常規(guī)的類型。其作用為：進(jìn)行數(shù)據(jù)的持久化保存。來看詳細(xì)內(nèi)容。

對(duì)象必須實(shí)現(xiàn)NSCodeing協(xié)議和NSCopying協(xié)議。

@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  
#pragma mark NSCoding  
- (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;  
}  
#pragma mark NSCopying  
- (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;  
} 

獲取歸檔文件

- (NSString *)dataFilePath {  
    NSArray *paths = NSSearchPathForDirectoriesInDomains( NSDocumentDirectory, NSUserDomainMask, YES);  
    NSString *documentsDirectory = [paths objectAtIndex:0];  
    return [documentsDirectory stringByAppendingPathComponent:@"archive"];  
} 

對(duì)數(shù)據(jù)進(jìn)行歸檔

FourLines *fourLines = [[FourLines alloc] init];  
    fourLines.field1 = field1.text;  
    fourLines.field2 = field2.text;  
    fourLines.field3 = field3.text;  
    fourLines.field4 = field4.text;  
//對(duì)數(shù)據(jù)進(jìn)行歸檔  
    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];    

獲取歸檔數(shù)據(jù)

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];         
} 

小結(jié)：iPhone應(yīng)用開發(fā)之模型對(duì)象歸檔的內(nèi)容介紹完了，希望通過本文對(duì)你有所幫助！