如何在 NSUserDefaults 中存储自定义对象 [英] How to store custom objects in NSUserDefaults

问题描述

好的，所以我一直在摸索，我意识到我的问题，但我不知道如何解决它.我制作了一个自定义类来保存一些数据.我为这个类制作对象，我需要它们在会话之间持续.在我将所有信息放入 NSUserDefaults 之前，但这不起作用.

Alright, so I've been doing some poking around, and I realize my problem, but I don't know how to fix it. I have made a custom class to hold some data. I make objects for this class, and I need to them to last between sessions. Before I was putting all my information in NSUserDefaults, but this isn't working.

-[NSUserDefaults setObject:forKey:]: Attempt to insert non-property value '<Player: 0x3b0cc90>' of class 'Player'.

这是我将自定义类Player"放入 NSUserDefaults 时得到的错误消息.现在，我已经读到显然 NSUserDefaults 只存储某些类型的信息.那么如何将我的对象放入 NSUSerDefaults 中?

That is the error message I get when I put my custom class, "Player", in the NSUserDefaults. Now, I've read up that apparently NSUserDefaults only stores some types of information. So how an I get my objects into NSUSerDefaults?

我读到应该有一种方法可以编码"我的自定义对象然后将其放入，但我不确定如何实现它，将不胜感激！谢谢！

I read that there should be a way to to "encode" my custom object and then put it in, but I'm not sure how to implement it, help would be appreciated! Thank you!

****编辑****

好的，所以我使用了下面给出的代码(谢谢！)，但我仍然遇到一些问题.基本上，代码现在崩溃了，我不知道为什么，因为它没有给出任何错误.也许我错过了一些基本的东西，我太累了，但我们会看到的.这是我的自定义类播放器"的实现:

Alright, so I worked with the code given below (Thank you!), but I'm still having some issues. Basically, the code crashes now and I'm not sure why, because it doesn't give any errors. Perhaps I'm missing something basic and I'm just too tired, but we'll see. Here is the implementation of my Custom class, "Player":

@interface Player : NSObject {
    NSString *name;
    NSNumber *life;
    //Log of player's life
}
//Getting functions, return the info
- (NSString *)name;
- (int)life;


- (id)init;

//These are the setters
- (void)setName:(NSString *)input; //string
- (void)setLife:(NSNumber *)input; //number    

@end

实施文件:

#import "Player.h"
@implementation Player
- (id)init {
    if (self = [super init]) {
        [self setName:@"Player Name"];
        [self setLife:[NSNumber numberWithInt:20]];
        [self setPsnCounters:[NSNumber numberWithInt:0]];
    }
    return self;
}

- (NSString *)name {return name;}
- (int)life {return [life intValue];}
- (void)setName:(NSString *)input {
    [input retain];
    if (name != nil) {
        [name release];
    }
    name = input;
}
- (void)setLife:(NSNumber *)input {
    [input retain];
    if (life != nil) {
        [life release];
    }
    life = input;
}
/* This code has been added to support encoding and decoding my objecst */

-(void)encodeWithCoder:(NSCoder *)encoder
{
    //Encode the properties of the object
    [encoder encodeObject:self.name forKey:@"name"];
    [encoder encodeObject:self.life forKey:@"life"];
}

-(id)initWithCoder:(NSCoder *)decoder
{
    self = [super init];
    if ( self != nil )
    {
        //decode the properties
        self.name = [decoder decodeObjectForKey:@"name"];
        self.life = [decoder decodeObjectForKey:@"life"];
    }
    return self;
}
-(void)dealloc {
    [name release];
    [life release];
    [super dealloc];
}
@end

这就是我的课程，非常直接，我知道它可以用于制作我的对象.所以这里是 AppDelegate 文件的相关部分(我称之为加密和解密函数):

So that's my class, pretty straight forward, I know it works in making my objects. So here is the relevant parts of the AppDelegate file (where I call the encryption and decrypt functions):

@class MainViewController;

@interface MagicApp201AppDelegate : NSObject <UIApplicationDelegate> {
    UIWindow *window;
    MainViewController *mainViewController;
}

@property (nonatomic, retain) IBOutlet UIWindow *window;
@property (nonatomic, retain) MainViewController *mainViewController;

-(void)saveCustomObject:(Player *)obj;
-(Player *)loadCustomObjectWithKey:(NSString*)key;


@end

然后是实现文件的重要部分:

And then the important parts of the implementation file:

    #import "MagicApp201AppDelegate.h"
    #import "MainViewController.h"
    #import "Player.h"

    @implementation MagicApp201AppDelegate


    @synthesize window;
    @synthesize mainViewController;


    - (void)applicationDidFinishLaunching:(UIApplication *)application {
    NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults];
        //First check to see if some things exist
        int startup = [prefs integerForKey:@"appHasLaunched"];
        if (startup == nil) {
//Make the single player 
        Player *singlePlayer = [[Player alloc] init];
        NSLog([[NSString alloc] initWithFormat:@"%@
%d
%d",[singlePlayer name], [singlePlayer life], [singlePlayer psnCounters]]); //  test
        //Encode the single player so it can be stored in UserDefaults
        id test = [MagicApp201AppDelegate new];
        [test saveCustomObject:singlePlayer];
        [test release];
}
[prefs synchronize];
}

-(void)saveCustomObject:(Player *)object
{ 
    NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults];
    NSData *myEncodedObject = [NSKeyedArchiver archivedDataWithRootObject:object];
    [prefs setObject:myEncodedObject forKey:@"testing"];
}

-(Player *)loadCustomObjectWithKey:(NSString*)key
{
    NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults];
    NSData *myEncodedObject = [prefs objectForKey:key ];
    Player *obj = (Player *)[NSKeyedUnarchiver unarchiveObjectWithData: myEncodedObject];
    return obj;
}

Eeee，对所有代码感到抱歉.只是想帮忙.基本上，该应用程序将启动然后立即崩溃.我已经把它缩小到应用程序的加密部分，这就是它崩溃的地方，所以我做错了什么，但我不确定是什么.再次感谢您的帮助，谢谢！

Eeee, sorry about all the code. Just trying to help. Basically, the app will launch and then crash immediatly. I've narrowed it down to the encryption part of the app, that's where it crashes, so I'm doing something wrong but I'm not sure what. Help would be appreciated again, thank you!

(我还没有开始解密，因为我还没有开始加密.)

(I haven't gotten around to decrypting yet, as I haven't gotten encrypting working yet.)

推荐答案

在您的 Player 类上，实现以下两个方法(用与您自己的对象相关的内容替换对 encodeObject 的调用):

On your Player class, implement the following two methods (substituting calls to encodeObject with something relevant to your own object):

- (void)encodeWithCoder:(NSCoder *)encoder {
    //Encode properties, other class variables, etc
    [encoder encodeObject:self.question forKey:@"question"];
    [encoder encodeObject:self.categoryName forKey:@"category"];
    [encoder encodeObject:self.subCategoryName forKey:@"subcategory"];
}

- (id)initWithCoder:(NSCoder *)decoder {
    if((self = [super init])) {
        //decode properties, other class vars
        self.question = [decoder decodeObjectForKey:@"question"];
        self.categoryName = [decoder decodeObjectForKey:@"category"];
        self.subCategoryName = [decoder decodeObjectForKey:@"subcategory"];
    }
    return self;
}

从 NSUserDefaults 读取和写入:

- (void)saveCustomObject:(MyObject *)object key:(NSString *)key {
    NSData *encodedObject = [NSKeyedArchiver archivedDataWithRootObject:object];
    NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
    [defaults setObject:encodedObject forKey:key];
    [defaults synchronize];

}

- (MyObject *)loadCustomObjectWithKey:(NSString *)key {
    NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
    NSData *encodedObject = [defaults objectForKey:key];
    MyObject *object = [NSKeyedUnarchiver unarchiveObjectWithData:encodedObject];
    return object;
}

无耻地借用代码:在 nsuserdefaults 中保存类

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