NSMutableDictionary "unrecognized selector sent to instance" NSMutableDictionary“未识别的选择器发送到实例”

Question

    -(void)saveDictionary:(int)counter
    {
        NSString *path=[[NSBundle mainBundle] pathForResource:@"Data" ofType:@"plist"];
        NSString *test = [NSString stringWithFormat:@"%d", counter];
        [theDictionary setObject:test forKey:@"Counter"]; <---- Error
        [theDictionary writeToFile:path atomically:YES];
    }

    - (void)applicationDidEnterBackground:(UIApplication *)application
    {
        [self saveDictionary:[_viewController counter]];
    }

错误：

-[NSCFString setObject:forKey:]: unrecognized selector sent to instance
*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[NSCFString setObject:forKey:]: unrecognized selector sent to instance

我可以从plist中加载"Counter"的值。如果我想要保存相同关键字“Counter”的新值……出现错误。需要帮助，已经花费了几个小时。

再见

这是初始化theDictionary的代码：

-(void)initDictionary {
    if (theDictionary == nil) {
        NSString *path=[[NSBundle mainBundle] pathForResource:@"Data" ofType:@"plist"];
        theDictionary = [[NSMutableDictionary alloc] initWithContentsOfFile:path];
        theString = [theDictionary objectForKey:@"Counter"];
    }
}

我找到了！

theString = [[NSString alloc] initWithFormat:[theDictionary objectForKey:@"Counter"]];

感谢大家的支持！

- Konobi

Answer 1

这是因为存储在theDictionary中的对象实际上是NSString，而NSString没有包含名为-setObject:forKey的方法。请检查代码中任何分配theDictionary的地方，并确保它实际上是一个NSMutableDictionary。

- Mark Adams

Answer 2

检查初始化...你可以这样做。

NSMutableDictionary *dictoForSyncing = [[NSMutableArray alloc] init];

- Martin Jacob

Answer 3

看起来theDictionary是一个字符串而不是NSMutableDictionary。它在哪里创建的？同时发生了什么事情？

- Kay

Answer 4

这意味着'theDictionary'根本不是一个字典。很可能它早些时候被释放了，某个NSString取代了它。

你正在使用ARC吗？'theDictionary'定义在哪里。

你尝试过僵尸工具来跟踪这个问题吗？那应该会有所帮助。

- Firoze Lafeer

Answer 5

看起来你的属性theDictionary实际上不是一个字典，而是一个字符串(NSString)。请问theDictionary定义在哪里？

- occulus

Answer 6

NSMutableArray *myObjFromFile = ....;
NSMutableDictionary *tmpDictFromFile = 
  [[[myObjFromFile objectAtIndex:xx] mutableCopy]; mutableCopy];

[tmpDictFromFile setObject:"YOUR OBJECT"
                    forKey:"YOUR KEY"];

- ArNo