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iOS存储的三种方式

时间:2015-06-07 18:47:06      阅读:156      评论:0      收藏:0      [点我收藏+]

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iOS中存储的3中方式:

1.NSUserDefaults

注意存储基本对象类型是没有问题的,但是要存储自定义对象,则要将对象内所有的属性(或是需要存储的属性)序列化,实现NSCoding协议序列化。

存:
[[NSUserDefaults standardUserDefaults] setValue:@"yellow" forKey:@"color"]; [[NSUserDefaults standardUserDefaults] synchronize];
取:
NSString *color = [[NSUserDefaults standardUserDefaults] objectForKey:@"color"];

 对于存储的是自定义的对象:(示例Contact的序列化)

#import <Foundation/Foundation.h>

@interface Contact : NSObject <NSCoding>

@property (nonatomic,retain) NSString *name;
@property (nonatomic,retain) NSString *phoneNumber;

+ (id)contactsWithName:(NSString *)aName phoneNumber:(NSString *)aPhoneNumber;

@end

 

#import "Contact.h"

#define
kNameKey @"NameKey" #define kPhoneNumberKey @"PhoneNumberKey" @implementation Contact - (id)initWithName:(NSString *)aName phoneNumber:(NSString *)aPhoneNumber { if (self = [super init]) { self.name = aName; self.phoneNumber = aPhoneNumber; } return self; } //初始化配套的便利方法 ,静态方法中的self 不代表当前类的对象,代表当前类本身 + (id)contactsWithName:(NSString *)aName phoneNumber:(NSString *)aPhoneNumber { return [[[self alloc] initWithName:aName phoneNumber:aPhoneNumber] autorelease]; } //对象序列化的两个协议方法 //对象序列化的方法,把对象的所有属性编码到本地 - (void)encodeWithCoder:(NSCoder *)aCoder { [aCoder encodeObject:_name forKey:kNameKey]; [aCoder encodeObject:_phoneNumber forKey:kPhoneNumberKey]; } //对象反序列化的方法 - (id)initWithCoder:(NSCoder *)aDecoder { if(self = [super init]) { self.name = [aDecoder decodeObjectForKey:kNameKey]; self.phoneNumber = [aDecoder decodeObjectForKey:kPhoneNumberKey]; } return self; }

 

2.沙盒

- (void)viewDidLoad 
{
    [super viewDidLoad];
    
    NSMutableDictionary *savedDic = [[NSMutableDictionary alloc] initWithContentsOfFile:[self dataFilePath]];
    
    //如果第一次进入,从userdefault中取不到数据,手动创建一个字典
    if (!savedDic)
    {
        self.dic = [NSMutableDictionary dictionaryWithCapacity:0];
    }
    else 
    {
        self.dic = savedDic;
    }
    //注册一个即将进入后台的通知
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(saveData) name:UIApplicationWillResignActiveNotification object:nil];
    
}

//返回文件的路径
- (NSString *)dataFilePath
{
    //沙盒
    //获得沙盒下面Documents文件夹的路径
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSLog(@"paths   %@",paths);
    NSString *path = [paths objectAtIndex:0];
    //在documents 路径下,追加一个文件路径
    NSString *filePath = [path stringByAppendingPathComponent:@"select.plist"];
    
    return filePath;           
}

- (void)saveData
{
    //字典当中存储的value 必须是  array dictionary Boolean data date nsnumber nsstring
    //把一个字典写到文件中,实际上是按照plist 的格式去组织数据的
    [_dic writeToFile:[self dataFilePath] atomically:YES];
    NSMutableDictionary *savedDic = [[NSMutableDictionary alloc] initWithContentsOfFile:[self dataFilePath]];
}

 

3.sqlite

 
 
 

iOS存储的三种方式

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原文地址:http://www.cnblogs.com/renlipeng/p/4558798.html

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