IOS學習筆記二十三對象歸檔(NSKeyedArchiver、NSKeyedUnArchiver、NSCodeing)

1、NSKeyedArchiver、NSKeyedUnArchiver

1）、archiveRootObject:toFile 歸檔對象到這個路徑文件

2）、unarchiveObjectWithFile:從這個路徑文件把對象進行恢復(fù)

對象歸檔這里我們可以理解Android里面的序列化，就是把對象保存到文件持久化，Android里面進行持久化的必須實現(xiàn)Serializable和Parcelable，然后IOS里面持久化必須實現(xiàn)NSCodeing協(xié)議，IOS進行持久化操作一般需要NSKeyedArchiver實現(xiàn)。
 
2、NSCodeing協(xié)議

1）、initWithCoder：該方法恢復(fù)對象

2）、encodeWithCoder：歸檔該對象

 
3、測試Demo(把Dictionary和普通對象進行對象歸檔)

IApple.h

    #import <Foundation/Foundation.h>
    #ifndef IApple_h
    #define IApple_h
    @interface IApple : NSObject <NSCoding>
    @property (nonatomic, copy) NSString *color;
    @property (nonatomic, assign) double weight;
    @property (nonatomic, assign) int size;
    -(id)initWithColor:(NSString *) color weight:(double) weight size:(int) size;
    @end
     
    #endif /* IApple_h */


IApple.m

    #import  "IApple.h"
    #import <Foundation/Foundation.h>
    @implementation IApple
    @synthesize color = _color;
    @synthesize weight = _weight;
    @synthesize size = _size;
    -(id)initWithColor:(NSString *) color weight:(double) weight size:(int) size
    {
        if (self = [super init])
        {
            self.color = color;
            self.weight = weight;
            self.size = size;
        }
        return self;
    }
    -(NSString *)description
    {
        return [NSString stringWithFormat:@"<IApple [color = %@, weight = %g, _size = %d]>", self.color, self.weight, self.size];
    }
     
    -(void)encodeWithCoder:(NSCoder *)aCoder
    {
        [aCoder encodeObject:_color forKey:@"color"];
        [aCoder encodeDouble:_weight forKey:@"weight"];
        [aCoder encodeInt:_size forKey:@"size"];
    }
    -(id) initWithCoder:(NSCoder *)aDecoder
    {
        _color = [aDecoder decodeObjectForKey:@"color"];
        _weight = [aDecoder decodeDoubleForKey:@"weight"];
        _size = [aDecoder decodeIntForKey:@"size"];
        return self;
    }
     
    @end


main.m

    #import "IApple.h"
    int main(int argc, char * argv[]) {
        @autoreleasepool {
            
            
            //在document目錄下創(chuàng)建一個chenyu.txt空文件
            NSArray *docPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
            NSString *path = [docPaths objectAtIndex:0];
            NSLog(@"document path:%@", path);
            
            NSFileManager *fileManager = [NSFileManager defaultManager];
            NSString *chenyuPath = [path stringByAppendingPathComponent:@"chenyu.txt"];
            BOOL isSuccess = [fileManager createFileAtPath:chenyuPath contents:nil attributes:nil];
            if (isSuccess) {
                NSLog(@"make chenyu.txt success");
            } else {
                NSLog(@"make chenyu.txt fail");
            }
        
            //用NSKeyedArchiver進行對象歸檔
            NSDictionary *dic = [NSDictionary dictionaryWithObjectsAndKeys:[NSNumber numberWithInt:10], @"oc", [NSNumber numberWithInt:20], @"java", [NSNumber numberWithInt:30], @"c++", nil];
            [NSKeyedArchiver archiveRootObject:dic toFile:chenyuPath];
            NSLog(@"123");
            //利用NSKeyedUnarchiver進行恢復(fù)對象
            NSDictionary *dic1 = [NSKeyedUnarchiver unarchiveObjectWithFile:chenyuPath];
            NSLog(@"oc value is %@", [dic1 valueForKey:@"oc"]);
            NSLog(@"java value is %@", [dic1 valueForKey:@"java"]);
            NSLog(@"c++ value is %@", [dic1 valueForKey:@"c++"]);
     
            //我們先看下chenyu.txt是什么文件，我們用file命令看下 file chenyu.txt,發(fā)現(xiàn)是二進制文件
    //        file chenyu.txt
    //        chenyu.txt: Apple binary property list
            //下面為chenyu.txt文件的內(nèi)容，我是用vim打開的
    //   bplist00?^A^B^C^D^E^F^Z^[X$versionX$objectsY$archiverT$top^R^@^A<86> ￥^G^H^Q^R^SU$nulló
    //            ^K^L^N^PWNS.keysZNS.objectsV$class?^M<80>^B?^O<80>^C<80>^DRoc^P ò^T^U^V^WZ$classnameX$classes\NSDictionary￠^X^Y\NSDictionaryXNSObject_^P^ONSKeyedArchiver?^\^]Troot<80>^A^H^Q^Z#-27=CJR]dfhjlnqsx<83><8c><99><9c>?2??ì^@^@^@^@^@^@^A^A^@^@^@^@^@^@^@^^^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@?
            
            //我們再用chenyu.txt歸檔IApple對象
            IApple *apple = [[IApple alloc] initWithColor:@"red" weight:5.6 size:20];
            IApple *apple1 = [[IApple alloc] initWithColor:@"wihte" weight:6.6 size:30];
            
            //用NSKeyedArchiver進行IApple對象歸檔
            [NSKeyedArchiver archiveRootObject:apple toFile:chenyuPath];
            [NSKeyedArchiver archiveRootObject:apple1 toFile:chenyuPath];
            
            IApple *saveApple = [NSKeyedUnarchiver unarchiveObjectWithFile:chenyuPath];
            NSLog(@"saveApple is %@", saveApple);
       }
    }

 
4、運行結(jié)果

    2018-07-22 00:08:57.804831+0800 cyTest[37026:15851965] document path:/Users/ls/Library/Developer/CoreSimulator/Devices/3FF9B833-FAF8-4C30-A855-3D40A4EAE8A6/data/Containers/Data/Application/272166E9-67BC-4E6B-B79A-0FF9DA389D7D/Documents
    2018-07-22 00:08:57.810379+0800 cyTest[37026:15851965] make chenyu.txt success
    2018-07-22 00:08:57.813994+0800 cyTest[37026:15851965] 123
    2018-07-22 00:08:57.815001+0800 cyTest[37026:15851965] oc value is 10
    2018-07-22 00:08:57.815228+0800 cyTest[37026:15851965] java value is 20
    2018-07-22 00:08:57.815438+0800 cyTest[37026:15851965] c++ value is 30
    2018-07-22 00:08:57.822014+0800 cyTest[37026:15851965] saveApple is <IApple [color = wihte, weight = 6.6, _size = 30]>

 
5、問題思考

是不是每次只能保持一個對象到文件里面呢?暫時感覺是這樣的，后面遇到問題再分析。

 

 


作者：chen.yu
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