ios 如何在 NSDictionary 中添加字符串？
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How to add a string in a NSDictionary?
提问by Alexis
Possible Duplicate:
How to add to an NSDictionary
可能的重复：
如何添加到 NSDictionary
When I do that :
当我这样做时：
NSDictionary *dic = [NSDictionary dictionary];
[dic setValue:@"nvjd" forKey:@"name"];
my app just crash. I don't understand why. How should I add a string in a dictionary ?
我的应用程序崩溃了。我不明白为什么。我应该如何在字典中添加字符串？
回答by dasblinkenlight
You need to make your dictionary mutable, otherwise it would not respond to the setValue:forKey:selector:
你需要让你的字典mutable，否则它不会响应setValue:forKey:选择器：
NSMutableDictionary *dic = [NSMutableDictionary dictionary];
This is a common pattern in cocoa: you often see classes declared in pairs: NSArray/NSMutableArray, NSSet/NSMutableSet, NSString/NSMutableString, and so on. Mutable version is capable of doing everything that the immutable version can do, but it also supports operations that change its content.
这是可可中的常见模式：您经常看到成对声明的类：NSArray/ NSMutableArray、NSSet/ NSMutableSet、NSString/NSMutableString等等。可变版本能够做不可变版本可以做的所有事情，但它也支持改变其内容的操作。
回答by janusfidel
NSMutableDictionary *dic = [NSMutableDictionary dictionary];
[dic setValue:@"nvjd" forKey:@"name"];
or
或者
NSDictionary *dic = [NSDictionary dictionaryWithObjectsAndKeys:@"nvjd",@"name" nil];
回答by Alladinian
You have two options. Either you initialize your NSDictionarywith a key/value pair (or more than one), or create an NSMutableDictionaryand add it later.
你有两个选择。要么NSDictionary使用键/值对（或多个）初始化，要么创建一个NSMutableDictionary并稍后添加。
// Immutable
NSDictionary *dic = [NSDictionary dictionaryWithObject:@"nvjd" forKey:@"name"];
// Mutable
NSMutableDictionary *dic = [NSMutableDictionary dictionary];
[dic setValue:@"nvjd" forKey:@"name"];
