NSMutableArray addObjects - 无法识别的选择器 [英] NSMutableArray addObjects - unrecognized-selector

问题描述

这是我初始化NSMutablearray的方法。我将cityList的内容复制到cityArray中。两者都是NSMutableArray。仅供参考，我使用extern声明了'cityArray'。

This is how I initialize my NSMutablearray. I copy the content of cityList into cityArray. Both are NSMutableArray. FYI, I declared the'cityArray' using extern.

cityArray = [[NSMutableArray alloc] init];

[cityArray addObjectsFromArray:cityList];

然后，在另一个类的其他方法中，我试图在'cityArray'中再添加一个对象我就是这样做的。但是当它运行这行代码时它会继续崩溃。

Then, in other method in another class, I tried to to add one more object into 'cityArray' This is how I do it. But it keep crashing when it run this line of code.

NSString *allCities = @"All Cities";
[[cityArray valueForKey:@"cityName"] addObject:allCities];

这是来自控制台'[__ NSArrayI addObject：]：无法识别的选择器发送到实例0x6292de0''。

This is from the console '[__NSArrayI addObject:]: unrecognized selector sent to instance 0x6292de0''.

但如果我用setvalue：forkey：测试它，它可以工作，但这不是我想要的。我希望将新数据添加到列表的底部。

But if I test it with setvalue:forkey:, it works but that is not what I want. I want the new data to be added into the bottom of the list.

推荐答案

NSArray 未实现 valueForKey：。您需要 NSDictionary 或使用 objectAtIndex：。

An NSArray doesn't implement valueForKey:. Your want either an NSDictionary or use objectAtIndex:.

您的第二部分代码应为：

Your second section of code should read:

NSString *allCities = @"All Cities";
[cityArray addObject:allCities];

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