Question

我有一个以NSMutableDictionary作为属性的类：

@interface Alibi : NSObject <NSCopying>
@property (nonatomic, copy) NSMutableDictionary * alibiDetails;
@end

使用以下构造函数：

- (Alibi *)init
{
    self = [super init];
    _alibiDetails = [NSMutableDictionary dictionary];
    return self;
}

和复制方法：

- (Alibi *)copyWithZone:(NSZone *)zone
{
    Alibi *theCopy = [[Alibi alloc] init];
    theCopy.alibiDetails = [self.alibiDetails mutableCopy];    
    return theCopy;
}

当我尝试调用setObject:ForKey:时，我收到运行时错误mutating method sent to immutable object。

我在视图控制器中将Alibi对象声明为@property (copy, nonatomic) Alibi * theAlibi;，并使用self.theAlibi = [[Alibi alloc] init];中的viewDidLoad对其进行初始化。

崩溃的线是：

NSString * recipient;
recipient = @"Boss";
[self.theAlibi.alibiDetails setObject:recipient forKey:@"Recipient"];

请告诉我这里我做错了什么。我在iPhone上为iOS 5编码。

Answer 1

你有一个'copy'属性，这意味着 - 你的NSMutableDictionary将调用-copy方法并在分配给合成的实例变量之前返回一个常规的NSDictionary。 This thread提供了一些有关解决此问题的选项的信息。

Answer 2

为了完成这个主题，我将在下面包含我修订的Alibi课程，这可以按照我的要求进行。如果有人注意到任何内存泄漏或其他问题，那将不胜感激。

@implementation Alibi

NSMutableDictionary *_details;

- (Alibi *)init
{
    self = [super init];
    _details = [NSMutableDictionary dictionary];
    return self;
}

- (NSMutableDictionary *)copyDetails
{
    return [_details mutableCopy];
}

- (NSMutableDictionary *)setDetails:(NSMutableDictionary *)value
{
    _details = value;
    return value;
}

- (void)addDetail:(id)value forKey:(id)key
{
    [_details setObject:value forKey:key];
}

- (id)getDetailForKey:(id)key
{
    return [_details objectForKey:key];
}

- (Alibi *)copyWithZone:(NSZone *)zone
{
    Alibi *theCopy = [[Alibi alloc] init];

    theCopy.serverId = [self.serverId copyWithZone:zone];
    theCopy.user = [self.user copyWithZone:zone];
    theCopy.startTime = [self.startTime copyWithZone:zone];
    theCopy.endTime = [self.endTime copyWithZone:zone];
    [theCopy setDetails:[self copyDetails]];

    return theCopy;
}

@end

NSMutableDictionary与“发送到不可变对象的变异消息”崩溃

2 个答案: