在NSUserDefaults中将自定义对象存储在NSMutableArray中

问题描述：

我最近一直试图将我的iPhone应用程序的搜索结果存储在NSUserDefaults集合中。我也使用它来成功保存用户注册信息，但由于某种原因，试图存储自定义位置类的NSMutableArray始终为空。在NSUserDefaults中将自定义对象存储在NSMutableArray中

我试图转换的NSMutableArray到NSData的元素作为这个帖子的，但我得到了相同的结果（Possible to save an integer array using NSUserDefaults on iPhone?）

我已经尝试了代码示例：

节省：

[prefs setObject:results forKey:@"lastResults"]; 
[prefs synchronize];

或

NSData *data = [NSData dataWithBytes:&results length:sizeof(results)]; 
[prefs setObject:data forKey:@"lastResults"];

或

NSData *data = [NSKeyedArchiver archivedDataWithRootObject:results]; 
[prefs setObject:data forKey:@"lastResults"];

负载：

lastResults = (NSMutableArray *)[prefs objectForKey:@"lastResults"];

或

NSData *data = [prefs objectForKey:@"lastResults"]; 
memcpy(&lastResults, data.bytes, data.length);

或

NSData *data = [prefs objectForKey:@"lastResults"]; 
lastResults = [NSKeyedUnarchiver unarchiveObjectWithData:data];

经过以下建议下面我也implemente d NSCoder在我对象（忽略的NSString其临时的过度使用）：

#import "Location.h" 


@implementation Location 

@synthesize locationId; 
@synthesize companyName; 
@synthesize addressLine1; 
@synthesize addressLine2; 
@synthesize city; 
@synthesize postcode; 
@synthesize telephoneNumber; 
@synthesize description; 
@synthesize rating; 
@synthesize priceGuide; 
@synthesize latitude; 
@synthesize longitude; 
@synthesize userLatitude; 
@synthesize userLongitude; 
@synthesize searchType; 
@synthesize searchId; 
@synthesize distance; 
@synthesize applicationProviderId; 
@synthesize contentProviderId; 

- (id) initWithCoder: (NSCoder *)coder 
{ 
    if (self = [super init]) 
    { 
     self.locationId = [coder decodeObjectForKey:@"locationId"]; 
     self.companyName = [coder decodeObjectForKey:@"companyName"]; 
     self.addressLine1 = [coder decodeObjectForKey:@"addressLine1"]; 
     self.addressLine2 = [coder decodeObjectForKey:@"addressLine2"]; 
     self.city = [coder decodeObjectForKey:@"city"]; 
     self.postcode = [coder decodeObjectForKey:@"postcode"]; 
     self.telephoneNumber = [coder decodeObjectForKey:@"telephoneNumber"]; 
     self.description = [coder decodeObjectForKey:@"description"]; 
     self.rating = [coder decodeObjectForKey:@"rating"]; 
     self.priceGuide = [coder decodeObjectForKey:@"priceGuide"]; 
     self.latitude = [coder decodeObjectForKey:@"latitude"]; 
     self.longitude = [coder decodeObjectForKey:@"longitude"]; 
     self.userLatitude = [coder decodeObjectForKey:@"userLatitude"]; 
     self.userLongitude = [coder decodeObjectForKey:@"userLongitude"]; 
     self.searchType = [coder decodeObjectForKey:@"searchType"]; 
     self.searchId = [coder decodeObjectForKey:@"searchId"]; 
     self.distance = [coder decodeObjectForKey:@"distance"]; 
     self.applicationProviderId = [coder decodeObjectForKey:@"applicationProviderId"]; 
     self.contentProviderId = [coder decodeObjectForKey:@"contentProviderId"]; 
    } 
} 

- (void) encodeWithCoder: (NSCoder *)coder 
{ 
    [coder encodeObject:locationId forKey:@"locationId"]; 
    [coder encodeObject:companyName forKey:@"companyName"]; 
    [coder encodeObject:addressLine1 forKey:@"addressLine1"]; 
    [coder encodeObject:addressLine2 forKey:@"addressLine2"]; 
    [coder encodeObject:city forKey:@"city"]; 
    [coder encodeObject:postcode forKey:@"postcode"]; 
    [coder encodeObject:telephoneNumber forKey:@"telephoneNumber"]; 
    [coder encodeObject:description forKey:@"description"]; 
    [coder encodeObject:rating forKey:@"rating"]; 
    [coder encodeObject:priceGuide forKey:@"priceGuide"]; 
    [coder encodeObject:latitude forKey:@"latitude"]; 
    [coder encodeObject:longitude forKey:@"longitude"]; 
    [coder encodeObject:userLatitude forKey:@"userLatitude"]; 
    [coder encodeObject:userLongitude forKey:@"userLongitude"]; 
    [coder encodeObject:searchType forKey:@"searchType"]; 
    [coder encodeObject:searchId forKey:@"searchId"]; 
    [coder encodeObject:distance forKey:@"distance"]; 
    [coder encodeObject:applicationProviderId forKey:@"applicationProviderId"]; 
    [coder encodeObject:contentProviderId forKey:@"contentProviderId"]; 

}

答

对于阵列中加载自定义对象，这是我用抢的数组：

NSUserDefaults *currentDefaults = [NSUserDefaults standardUserDefaults]; 
NSData *dataRepresentingSavedArray = [currentDefaults objectForKey:@"savedArray"]; 
if (dataRepresentingSavedArray != nil) 
{ 
    NSArray *oldSavedArray = [NSKeyedUnarchiver unarchiveObjectWithData:dataRepresentingSavedArray]; 
    if (oldSavedArray != nil) 
     objectArray = [[NSMutableArray alloc] initWithArray:oldSavedArray]; 
    else 
     objectArray = [[NSMutableArray alloc] init]; 
}

您应该检查从用户默认返回的数据不为零，因为我相信解除封存从零导致崩溃。

存档很简单，使用下面的代码：

[[NSUserDefaults standardUserDefaults] setObject:[NSKeyedArchiver archivedDataWithRootObject:objectArray] forKey:@"savedArray"];

由于f3lix指出的那样，你需要使你的自定义对象均符合欧盟的NSCoding协议。像下面添加方法应该做的伎俩：

- (void)encodeWithCoder:(NSCoder *)coder; 
{ 
    [coder encodeObject:label forKey:@"label"]; 
    [coder encodeInteger:numberID forKey:@"numberID"]; 
} 

- (id)initWithCoder:(NSCoder *)coder; 
{ 
    self = [super init]; 
    if (self != nil) 
    { 
     label = [[coder decodeObjectForKey:@"label"] retain]; 
     numberID = [[coder decodeIntegerForKey:@"numberID"] retain]; 
    } 
    return self; 
}

我已经将你的代码和实现NSCoder的对象复制到原型中，但是desp ite来自UserDefaults的NSData有数据，最终数组仍然有0的计数。任何想法？我会尝试将我的原型上传到某处 – 2009-02-13 16:31:50

答

请参阅“NSUserDefaults的为什么没能挽救的NSMutableDictionary在iPhone SDK？ “（Why NSUserDefaults failed to save NSMutableDictionary in iPhone SDK?）

如果你想（反）序列化的自定义对象，你必须提供的功能（反）序列化的数据（NSCoding协议）。该解决方案你是指与INT作品数组，因为数组是不是对象，而是一个连续的内存块。

我认为您的权利，我会看看到NSCoding（除非你有一个建议linky），本身是由上NSString的对象是所有的，所以我想我可以写我自己的串行器，并把它们全部放入一个字符串数组 – 2009-02-11 14:56:07

好吧，所以我已经实现了NSCode，但仍然没有使用NSArchiver – 2009-02-11 16:29:53

答

我认为它看起来像你的代码不保存结果阵列的问题。它的加载数据尝试使用

lastResults = [prefs arrayForKey:@"lastResults"];

这将返回数组s通过钥匙特化。

答

我会建议不要试图在默认数据库中存储这样的东西。

SQLite很容易拾取和使用。我在我的一个屏幕录像（http://pragprog.com/screencasts/v-bdiphone）中插入了一段关于我写的简单包装（您可以在不购买SC的情况下获得代码）。

在应用程序空间中存储应用程序数据要干净得多。

所有这一切说，如果它仍然是有道理的把这个数据放入默认的数据库，然后看到帖子f3lix张贴。

谢谢你的建议，但我真的不想开始编写SQL查询我在你的例子中看到）只是为了一个有几个字符串的对象 – 2009-02-11 16:58:39

答

我想你已经在你的initWithCoder方法得到一个错误，至少在所提供的代码，你不回的“自我”的对象。

- (id) initWithCoder: (NSCoder *)coder 
{ 
    if (self = [super init]) 
    { 
     self.locationId = [coder decodeObjectForKey:@"locationId"]; 
     self.companyName = [coder decodeObjectForKey:@"companyName"]; 
     self.addressLine1 = [coder decodeObjectForKey:@"addressLine1"]; 
     self.addressLine2 = [coder decodeObjectForKey:@"addressLine2"]; 
     self.city = [coder decodeObjectForKey:@"city"]; 
     self.postcode = [coder decodeObjectForKey:@"postcode"]; 
     self.telephoneNumber = [coder decodeObjectForKey:@"telephoneNumber"]; 
     self.description = [coder decodeObjectForKey:@"description"]; 
     self.rating = [coder decodeObjectForKey:@"rating"]; 
     self.priceGuide = [coder decodeObjectForKey:@"priceGuide"]; 
     self.latitude = [coder decodeObjectForKey:@"latitude"]; 
     self.longitude = [coder decodeObjectForKey:@"longitude"]; 
     self.userLatitude = [coder decodeObjectForKey:@"userLatitude"]; 
     self.userLongitude = [coder decodeObjectForKey:@"userLongitude"]; 
     self.searchType = [coder decodeObjectForKey:@"searchType"]; 
     self.searchId = [coder decodeObjectForKey:@"searchId"]; 
     self.distance = [coder decodeObjectForKey:@"distance"]; 
     self.applicationProviderId = [coder decodeObjectForKey:@"applicationProviderId"]; 
     self.contentProviderId = [coder decodeObjectForKey:@"contentProviderId"]; 
    } 

    return self; // this is missing in the example above 


}

我用

NSData *data = [NSKeyedArchiver archivedDataWithRootObject:results]; 
[prefs setObject:data forKey:@"lastResults"];

和

NSUserDefaults *currentDefaults = [NSUserDefaults standardUserDefaults]; 
NSData *dataRepresentingSavedArray = [currentDefaults objectForKey:@"lastResults"]; 
if (dataRepresentingSavedArray != nil) 
{ 
     NSArray *oldSavedArray = [NSKeyedUnarchiver unarchiveObjectWithData:dataRepresentingSavedArray]; 
     if (oldSavedArray != nil) 
       objectArray = [[NSMutableArray alloc] initWithArray:oldSavedArray]; 
     else 
       objectArray = [[NSMutableArray alloc] init]; 
}

和它的工作非常适合我。

与问候，

斯特凡

在NSUserDefaults中将自定义对象存储在NSMutableArray中

相关推荐