在 NSUserDefaults 中存储自定义对象答案

【问题标题】：Store Custom Objects in NSUserDefaults在 NSUserDefaults 中存储自定义对象
【发布时间】：2017-08-30 13:34:41
【问题描述】：

我正在尝试按如下方式存储自定义对象，但出现错误。

// store data
NSMutableArray *archiveArray = [NSMutableArray arrayWithCapacity:pOrderElements.count];
for (id orderObject in pOrderElements) {
    NSData *personEncodedObject = [NSKeyedArchiver archivedDataWithRootObject:orderObject];
    [archiveArray addObject:personEncodedObject];
}

NSUserDefaults *userData = [NSUserDefaults standardUserDefaults];
[userData setObject:archiveArray forKey:@"personDataArray"];


// retrive data
NSData *data = [userData objectForKey:@"personDataArray"];
// the following line throws an error
id retrieveData = [NSKeyedUnarchiver unarchiveObjectWithData:data];

这是我的 pOrderElements

(lldb) po pOrderElements
<__NSArrayM 0x174256b90>(
{
    category = 1;
    imagePath = "products/chicken-kabob.png";
    name = "Baked Chicken";
    price = "5.49";
}
)

由于未捕获的异常而终止应用程序 'NSInvalidArgumentException'，原因：'-[__NSCFArray 字节]：无法识别的选择器发送到实例 0x174264f40'

【问题讨论】：

How to store custom objects in NSUserDefaults的可能重复
我参考了以下答案，但我得到了错误stackoverflow.com/questions/19720611/…
你实现了编码器解码器吗？
don't post same questions again
这是重复的问题，但我已根据您的需要发布了完整的答案。请检查并告诉我@hotspring

标签： ios objective-c nsuserdefaults nskeyedarchiver nskeyedunarchiver

【解决方案1】：

首先您创建自定义类，如下所示。

CustomObject.h

#import <Foundation/Foundation.h>

@interface CustomObject : NSObject

@property(strong,nonatomic)NSString *name;

@end

CustomObject.m

#import "CustomObject.h"

@implementation CustomObject



- (void)encodeWithCoder:(NSCoder *)encoder {
    //Encode properties, other class variables, etc
    [encoder encodeObject:self.name forKey:@"name"];

}

- (id)initWithCoder:(NSCoder *)decoder {
    if((self = [super init])) {
        //decode properties, other class vars
        self.name = [decoder decodeObjectForKey:@"name"];

    }
    return self;
}

然后创建CustomObject类对象并存储在NSUserDefaults中

像这样存储你的对象

CustomObject *object =[CustomObject new];
object.name = @"test";

NSMutableArray *arr = [[NSMutableArray alloc]init];
[arr  addObject:object];

NSData *encodedObject = [NSKeyedArchiver archivedDataWithRootObject:arr];
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
[defaults setObject:encodedObject forKey:@"storeObject"];
[defaults synchronize];

像这样从NSUserDefaults 获取自定义对象

NSData *storedEncodedObject = [defaults objectForKey:@"storeObject"];
    NSArray *arrStoreObject = [NSKeyedUnarchiver unarchiveObjectWithData:storedEncodedObject];
    for (int i=0; i<arrStoreObject.count; i++)
    {
        CustomObject *storedObject = [arrStoreObject objectAtIndex:i];
        NSLog(@"%@",storedObject.name);

    }

【讨论】：

【解决方案2】：

您解压缩了不正确的对象。您将 NSArray 存储到 NSUserDefaults

NSArray * archiveArray = [userData objectForKey:@"personDataArray"];
for (NSData *personEncodedObject in archiveArray) {
    id personObject = [NSKeyedUnarchiver unarchiveObjectWithData:personEncodedObject];
}

【讨论】：