本文简单介绍NSUserDefaults的存、取、移除用法，代码如下：
[[NSUserDefaults standardUserDefaults] setObject:@"exampleObject" forKey:@"exampleKey"];//存
[[NSUserDefaults standardUserDefaults] objectForKey:@"exampleKey"];//取
[[NSUserDefaults standardUserDefaults] removeObjectForKey:@"exampleKey"];//移除
使用NSUserDefaults存储除NSArray、NSData、NSDictionary、NSString、NSNumber等基本数据类型之外的自定义类型，报错如下：
//存储一个包含TradeRecordModel类型的Model的Array到NSUserDefaults中
Attempt to set a non-property-list object (
"<TradeRecordModel: 0x60800024ae30>",
"<TradeRecordModel: 0x60800024ae30>",
"<TradeRecordModel: 0x60800024ae30>"
) as an NSUserDefaults/CFPreferences value for key myWalletTradeRecordList
要存储自定义类型的对象，用NSUserDefaults存储时要对其进行归档处理，取出时要先解档；
下面以NSUserDefaults存储自定义Model（TradeRecordModel）为例，代码如下：
/**
* TradeRecordModel.h
*/
@interface TradeRecordModel : NSObject <NSCoding>//首先遵守<NSCoding>代理
@property (nonatomic,strong) NSString * ID;
@property (nonatomic,strong) NSString * title;
@property (nonatomic,strong) NSString * change;
@property (nonatomic,strong) NSString * created_at;
HMSingletonH(TradeRecordModel)//单例模式
@end
/**
* TradeRecordModel.m
*/
@implementation TradeRecordModel
HMSingletonM(TradeRecordModel)//单例模式
-(void)setValue:(id)value forUndefinedKey:(NSString *)key{
if ([key isEqualToString:@"id"]) {
_ID = value;
}
}
#pragma mark NSCoding
//步骤二：实现NSCoding的两个代理
- (id)initWithCoder:(NSCoder *)aDecoder{
if (self == [super init]) {
_ID = [aDecoder decodeObjectForKey:@"id"];
_title = [aDecoder decodeObjectForKey:@"title"];
_change = [aDecoder decodeObjectForKey:@"change"];
_created_at = [aDecoder decodeObjectForKey:@"created_at"];
}
return self;
}
- (void)encodeWithCoder:(NSCoder *)aCoder{
[aCoder encodeObject:_ID forKey:@"id"];
[aCoder encodeObject:_title forKey:@"title"];
[aCoder encodeObject:_change forKey:@"change"];
[aCoder encodeObject:_created_at forKey:@"created_at"];
}
@end
这样model类的处理就告于段落了，在调用NSUserDefaults存储时，用下列代码进行处理：
TradeRecordModel *model = [TradeRecordModel new];
for (NSDictionary *dict in response) {
[model setValuesForKeysWithDictionary:dict];//设置model
NSData *data = [NSKeyedArchiver archivedDataWithRootObject:model];//归档model
NSLog(@"归档数据：%@",data)
[arr addObject:data];
}
[[NSUserDefaults standardUserDefaults] setObject:arr forKey:key];
[[NSUserDefaults standardUserDefaults] synchronize];
model的设置，参考链接:http://www.jianshu.com/p/76d6d1c56d3b。其余问题请参考自身实际情况；
在调用NSUserDefaults取出数据时，代码如下：
NSArray *arr = [[NSUserDefaults standardUserDefaults] objectForKey:key];
TradeRecordModel *model = [TradeRecordModel new];
for (NSData *data in arr) {
model = [NSKeyedUnarchiver unarchiveObjectWithData:data];//解档model
NSLog(@"解档数据：%@",model.ID)
[tradeRecordListArr addObject:model];
}
可变数组tradeRecordListArr中，就存储了你之前存储的那个model了。
此外，在此介绍一个NSUserDefaults的宏定义方法，代码：
//NSUserDefault缓存
#define SAVEDEFAULTS(value,key) [[NSUserDefaults standardUserDefaults] setObject:value forKey:key];\
[[NSUserDefaults standardUserDefaults] synchronize];
#define GETDEFAULTS(key) [[NSUserDefaults standardUserDefaults] objectForKey:key];
The end!
