使用NSKeyedArchiver 及NSCoding保存数据

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mob604756eb17db 2012-02-12 11:07:00

文章标签 hive 键值数据 #define bundle 文章分类 代码人生

- (NSMutableArray *)loadMarkersFromFilePath:(NSString *)filePath {
   NSMutableArray *markers = nil;
   if (filePath == nil || [filePath length] == 0 ||
       [[NSFileManager defaultManager] fileExistsAtPath:filePath] == NO) {
       markers = [[[NSMutableArray alloc] init] autorelease];
   } else {
       NSData *data = [[NSData alloc] initWithContentsOfFile:filePath];
       NSKeyedUnarchiver *vdUnarchiver = [[NSKeyedUnarchiver alloc] initForReadingWithData:data];
       markers = [vdUnarchiver decodeObjectForKey:kSaveKeyMarkerLines];
       [vdUnarchiver finishDecoding];
       [vdUnarchiver release];
       [data release];
   }
   return markers;

}

- (void)saveMarkers:(NSMutableArray *)markers toFilePath:(NSString *)filePath {
   NSMutableData *data = [[NSMutableData alloc] init];
   NSKeyedArchiver *vdArchiver = [[NSKeyedArchiver alloc] initForWritingWithMutableData:data];
   [vdArchiver encodeObject:markers forKey:kSaveKeyMarkerLines];
   [vdArchiver finishEncoding];
   [data writeToFile:filePath atomically:YES];
   [vdArchiver release];
   [data release];

}

==================================================================================

[NSString stringWithContentsOfFile:filepath encoding:NSUTF8StringEncoding error:nil];

-----------------------------------------------------------------------------------------------------------------------------------------------

 1 /*======================================================= 
 2 NSKeyedArchiver 
 3 ========================================================*/  
 4 NSString *str = @"abc";  
 5 NSString *astr = @"efg";  
 6 NSArray *Array = [NSArray arrayWithObjects:str, astr, nil];  
 7    
 8 //Save  
 9 NSString *Path = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0]; NSString *filename = [Path stringByAppendingPathComponent:@"test"];  
10 [NSKeyedArchiver archiveRootObject:Array toFile:filename];  
11//NSData *data =[NSKeyedArchiver archivedDataWithRootObject:Array];

12 str = @"a";  
13 astr = @"";  
14    
15 //load  
16 NSArray *arr = [NSKeyedUnarchiver unarchiveObjectWithFile: filename];  
17 str = [arr objectAtIndex:0];  
18 astr =  [arr objectAtIndex:1];  
19    
20 NSLog(@"str:%@",str);  
21 NSLog(@"astr:%@",astr);  
22    
23 /*======================================================= 
24 NSUserDefaults 
25 ========================================================*/  
26 NSString *str = @"abc";  
27 NSString *astr = @"efg";  
28 NSArray *Array = [NSArray arrayWithObjects:str, astr, nil];  
29    
30 //Save  
31 NSUserDefaults *SaveDefaults = [NSUserDefaults standardUserDefaults];  
32 [SaveDefaults setObject:Array forKey:@"SaveKey"];  
33    
34 str = @"a";  
35 astr = @"";  
36    
37 //load  
38 Array = [SaveDefaults objectForKey:@"SaveKey"];  
39 str = [Array objectAtIndex:0];  
40 astr = [Array objectAtIndex:1];  
41 NSLog(@"str:%@",str);  
42 NSLog(@"astr:%@",astr);  
43    
44 /*======================================================= 
45 writeToFile: 
46 ========================================================*/  
47 NSString *str = @"abc";  
48 NSString *astr = @"efg";  
49 NSArray *Array = [NSArray arrayWithObjects:str, astr, nil];  
50    
51 //Save  
52 NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);  
53 NSString *documentsDirectory = [paths objectAtIndex:0];  
54 if (!documentsDirectory) {  
55     NSLog(@"Documents directory not found!");  
56 }  
57 NSString *appFile = [documentsDirectory stringByAppendingPathComponent:@"Savedatas.plist"];  
58 [[NSArray arrayWithObjects:Array,nil] writeToFile:appFile atomically:NO];      
59    
60    
61 //load  
62 if([[NSFileManager defaultManager] fileExistsAtPath:appFile])  
63     self.SaveDataArray = [NSMutableArray arrayWithContentsOfFile:appFile];          
64 else  
65     self.SaveDataArray = [NSMutableArray arrayWithContentsOfFile:[[NSBundle mainBundle] pathForResource:@"Savedatas" ofType:@"plist"]];  
66 NSArray *strArray = [self.SaveDataArray objectAtIndex:0];  
67    
68 str = [strArray objectAtIndex:0];  
69 astr = [strArray objectAtIndex:1];

75 //坛子里的，搬过来。。。。。  
76 -(BOOL) writeApplicationData:(NSDictionary *)data  writeFileName:(NSString *)fileName  
77 {  
78     NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);  
79     NSString *documentsDirectory = [paths objectAtIndex:0];  
80     if (!documentsDirectory) {  
81         NSLog(@"Documents directory not found!");  
82         return NO;  
83     }  
84     NSString *appFile = [documentsDirectory stringByAppendingPathComponent:fileName];  
85     return ([data writeToFile:appFile atomically:YES]);  
86 }  
87    
88 -(id) readApplicationData:(NSString *)fileName  
89 {  
90     NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);  
91     NSString *documentsDirectory = [paths objectAtIndex:0];  
92     NSString *appFile = [documentsDirectory stringByAppendingPathComponent:fileName];  
93     NSDictionary *myData = [[[NSDictionary alloc] initWithContentsOfFile:appFile] autorelease];  
94     return myData;  
95 }

NSCoding 保存数据

为了将应用数据存储到硬盘中，iOS提供基本的文件API、Property List序列化、SQLite、CoreData以及NSCoding。对于轻量级的数据要求，NSCoding因其简单而成为一种比较合适的方式。

NSCoding是一个你需要在数据类上要实现的协议以支持数据类和数据流间的编码和解码。数据流可以持久化到硬盘。而实现NSCoding其实很简单，因此有时会很有用。相关代码如下：

 1 // 键值宏定义  
 2 #define SAMPLEDATA_KEY_STARS (@"stars")  
 3 #define SAMPLEDATA_KEY_TITLE (@"title")  
 4 #define SAMPLEDATA_KEY_ITEMS (@"items")  
 5  
 6 @interface SampleData : NSObject <NSCoding>{  
 7     int  starCount;  
 8     NSString  *titleText;  
 9     NSMutableDictionary  *items;  
10     int   tempNumber; //不保存的变量  
11 }  
12 @property(nonatomic,readwrite)  int starCount;  
13 @property (nonatomic, retain, readwrite) NSString *titleText;  
14 @property (nonatomic, retain, readwrite) NSMutableDictionary *items;  
15 @property(nonatomic,readwrite)  int tempNumber;  
16 @end  
17  
18 @implementation SampleData  
19 @synthesize starCount, titleText, items, tempNumber;  
20  
21 - (void)encodeWithCoder:(NSCoder*)coder  
22 {  
23     [coder encodeObject:titleText forKey:SAMPLEDATA_KEY_TITLE];  
24     [coder encodeObject:items forKey:SAMPLEDATA_KEY_ITEMS];  
25     [coder encodeInt:starCount forKey:SAMPLEDATA_KEY_STARS];  
26 }  
27 - (id)initWithCoder:(NSCoder*)decoder  
28 {  
29     if ((self = [super init])){ //被init:调用时使用默认值  
30         self.titleText = nil;  
31         self.items  = [[NSMutableDictionary alloc]init];  
32         starCount  = 0;  
33         tempNumber = 0;  
34         if (decoder==nil) {  
35             return self;  
36         }  
37  
38         // 取值前确认相应的键值是否存在。  
39         if ([decoder containsValueForKey:SAMPLEDATA_KEY_TITLE]) {  
40             self.titleText =   [decoder decodeObjectForKey:SAMPLEDATA_KEY_TITLE];  
41         }  
42         if ([decoder containsValueForKey:SAMPLEDATA_KEY_ITEMS]) {  
43             self.items  =   [decoder decodeObjectForKey:SAMPLEDATA_KEY_ITEMS];  
44         }  
45         if ([decoder containsValueForKey:SAMPLEDATA_KEY_STARS]) {  
46             starCount  =  [decoder decodeIntForKey:SAMPLEDATA_KEY_STARS];  
47         }  
48     }  
49     return self;  
50 }  
51 - (id)init {  
52     if ((self = [super init])){  
53         [self initWithCoder:nil];  
54     }  
55     return self;  
56 }  
57 @end