[数据存储之二]NSUserDefaults练习

た入场券 2022-08-18 12:10 123阅读 0赞

//  TestCodingProtocol.h
    //  block练习
    #import <Foundation/Foundation.h>
    
    @interface TestCodingProtocol : NSObject<NSCoding>
    #pragma mark- 持久化属性
    @property(nonatomic,copy,readwrite) NSString* myName;
    @property(nonatomic,assign,readwrite)NSInteger myIndex;
    #pragma mark- 实现协议方法
    - (void)encodeWithCoder:(NSCoder *)aCoder;
    - (id)initWithCoder:(NSCoder *)aDecoder;
    
    @end
    
    @interface TestCodingProtocolChild : TestCodingProtocol
    
    @property(nonatomic,assign,readwrite) NSInteger myIndexChild;
    -(void)encodeWithCoder:(NSCoder *)aCoder;
    -(id)initWithCoder:(NSCoder *)aDecoder;
    
    @end

//  TestCodingProtocol.m
    //  block练习
    
    #import "TestCodingProtocol.h"
    
    @implementation TestCodingProtocol
    
    -(void)encodeWithCoder:(NSCoder *)aCoder
    {
        if (aCoder) {
            [aCoder encodeObject:self.myName forKey:@"myName"];
            //self.myIndex为基础类型，不能用encodeObject
            [aCoder encodeInteger:self.myIndex forKey:@"myIndex"];
        }
    }
    
    -(id)initWithCoder:(NSCoder *)aDecoder
    {
        if (self = [super init]) {
            if (!aDecoder) {
                return self;
            }
            self.myName = [aDecoder decodeObjectForKey:@"myName"];
            self.myIndex = [aDecoder decodeIntegerForKey:@"myIndex"];
        }
        return self;
    }
    @end
    
    @implementation TestCodingProtocolChild
    
    -(void)encodeWithCoder:(NSCoder *)aCoder
    {
        [super encodeWithCoder:aCoder];
        [aCoder encodeInteger:self.myIndexChild forKey:@"myIndexChild"];
    }
    
    -(id)initWithCoder:(NSCoder *)aDecoder
    {
        if (self = [super initWithCoder:aDecoder]) {//这里如果用init的话，父类的内容得不到初始化。
            if (!aDecoder) {
                return self;
            }
            self.myIndexChild = [aDecoder decodeIntegerForKey:@"myIndexChild"];
        }
        return self;
    }
    @end

TestCodingProtocol* t = [[TestCodingProtocol alloc] init];
        t.myIndex = 5;
        t.myName = @"hello";
        
        TestCodingProtocolChild* tChild = [[TestCodingProtocolChild alloc] init];
        tChild.myIndex = 6;
        tChild.myName = @"child";
        tChild.myIndexChild = 7;
        //增加几个基础类型。
        NSString* s = @"helloworld";
        NSNumber* n = [NSNumber numberWithInteger:5];
        NSDate*   d = [NSDate date];
        NSData* dt = [NSKeyedArchiver archivedDataWithRootObject:t];
        NSData* dChild = [NSKeyedArchiver archivedDataWithRootObject:tChild];
        NSArray*  r = [NSArray arrayWithObjects:s,n,d, nil];

NSUserDefaults* ud = [NSUserDefaults standardUserDefaults];
        [ud setObject:r forKey:@"myData"];     //这里如果r里面带自己的类型实例的话，也不行,要转换成NSData
        [ud setObject:dt forKey:@"dt"];        //如果这个dt放入r里面，解析的时候就找不到特殊的标志了。
        [ud setObject:dChild forKey:@"dChild"];//这三句话在第二次进入前屏蔽掉，也能读到，说明已经存储了。
        
        
        id er = [ud objectForKey:@"myData"];
        id et = [ud objectForKey:@"dt"];
        id etChild = [ud objectForKey:@"dChild"];
        if (et && [et isKindOfClass:[NSData class]]) {
            TestCodingProtocol* buf = [NSKeyedUnarchiver unarchiveObjectWithData:et];
            NSLog(@"myIndex is %ld, myName is %@", buf.myIndex, buf.myName);
        }
        if (etChild && [etChild isKindOfClass:[NSData class]]) {
            TestCodingProtocolChild* buf  = [NSKeyedUnarchiver unarchiveObjectWithData:etChild];
            NSLog(@"myIndex is %ld, myName is %@, myIndexChild is %ld", buf.myIndex, buf.myName, buf.myIndexChild);
        }
        if ([er isKindOfClass:[NSArray class]]) {
            NSEnumerator* e = [er objectEnumerator];
            id obj;
            while (obj = [e nextObject]) {
                if ([obj isKindOfClass:[TestCodingProtocolChild class]]) {
                    NSLog(@"%@ 123",obj);
                }
                NSLog(@"%@",obj);
            }
        }

总结下吧：

1,这个nsuserdefaults支持nsstring,nsdata,nsnumber,nsarray,nsdictionary。

2,自己定义的类还的借助于nskeyedarchiver和nskeyedunarchiver进行与nsdata的转换，如果直接用nskeyedarchiver也可以，见coding协议练习。

3,保存文件的位置目前还没有找到～～

参考http://blog.csdn.net/chyroger/article/details/5785297