ios - NSMutableDictionary 转换成 __ NSCFString

Question

我正在开发一个 iOS 4 应用程序。

我有一个具有 NSMutableDictionary 属性的类:

@interface CardHelper : NSObject <NSXMLParserDelegate>{
    ...

    NSMutableDictionary* cards;

    ...
}

@property (nonatomic, readonly) NSMutableDictionary* cards;

- (id)initWithXMLFile:(NSString *)xmlFileName andLanguage:(NSString *)language;
...

我在这里创建了 NSMutableDictionary:

...
#define kNumCards 22
...

- (id)initWithXMLFile:(NSString *)xmlFileName andLanguage:(NSString *)language
{
    if (self = [super init])
    {
        userLanguage = [NSString stringWithString:language];

        cards = [NSMutableDictionary dictionaryWithCapacity: kNumCards];

        [self parseXMLFile:[self GetResourcePathFor:xmlFileName OfType:@"xml"]];

        return self;
    }
    else
        return nil;
}

我在这里添加元素:

- (void) parser:(NSXMLParser *)parser
  didEndElement:(NSString *)elementName
   namespaceURI:(NSString *)namespaceURI
  qualifiedName:(NSString *)qName
{
    NSLog(@"DidEndElement: %@", elementName);
    if ([elementName isEqualToString:@"card"])
    {
        [cards setObject:currentCard forKey:currentCard.Number];
        [currentCard release];
        currentCard = nil;

        return;
    }

    ...
}

CardHelper 对象是在一个名为 ViewController(我的应用程序的主视图 Controller )的类上创建的。从这个 View Controller 我展示了另一个:

- (IBAction)oneCardCliked:(id)sender
{
    oneViewController = [[OneCardViewController alloc] init];
    oneViewController.cardHelper = cardHelper;

    [self presentModalViewController:oneViewController animated:YES];
}

在 ViewController 中定义的 CardHelper:

@interface ViewController : UIViewController {
    ...
    CardHelper* cardHelper;
    ...
}
...

我将 cardHelper 传递给 OneCardViewController 以在那里使用。

但是，在 OneCardViewController我尝试获取 card来自 cards ，我知道卡片已从 NSMutableDictionary 转换至 NSCFString .

OneCardViewController 接口(interface):

@interface OneCardViewController : UIViewController {
    CardHelper* cardHelper;
    ...
}

@property (nonatomic, retain) CardHelper* cardHelper;

我在这里得到异常(exception):

- (void) setUpTarotGame
{
    int arcaneNumber;
    arcaneNumber = [cardHelper GenerateArcaneNumber];
    NSString* number = [NSString stringWithFormat:@"%d", arcaneNumber];
    if (cardHelper == nil) {
        NSLog(@"cardHelper nil");
        return;
    }
    if (cardHelper.cards == nil)
    {
        NSLog(@"cards nil");
        return;
    }
    else
        NSLog(@"cards count = %d", [cardHelper.cards count]);
    currentCard = [cardHelper.cards objectForKey:number];

    [self setCardImageWithArcane:arcaneNumber];
}

在这一行中抛出异常:

currentCard = [cardHelper.cards objectForKey:number];

你知道为什么吗？

Answer 1

它没有被转换，它正在被释放，内存被用于其他用途。

在您的 init 方法中，您没有保留这些对象:

userLanguage = [NSString stringWithString:language];
cards = [NSMutableDictionary dictionaryWithCapacity: kNumCards];

尝试

userLanguage = [language copy];
cards = [NSMutableDictionary alloc] initWithCapacity:kNumCards];

反而。