从NSArray获取字符串值 [英] Getting the string value from a NSArray

问题描述

我有一个 NSArrayController 和我当我得到 selectedObjects 并创建一个NSString的值 valueForKey：@Name它返回

I have a NSArrayController and I when I get the selectedObjects and create a NSString with the value of valueForKey:@"Name" it returns

(
    "This is still a work in progress "
)

，所有我想要的是文本在如何得到呢？也是，我的代码：

and all I want to have is the text in the "" how would I get that? also, this my code:

NSArray *arrayWithSelectedObjects = [[NSArray alloc] initWithArray:[arrayController selectedObjects]];

NSString *nameFromArray = [NSString stringWithFormat:@"%@", [arrayWithSelectedObjects valueForKey:@"Name"]];
NSLog(@"%@", nameFromArray);

编辑：数组中还有其他字符串

Edit: I also have other strings in the array

推荐答案

当你在数组上调用 valueForKey： > valueForKey：在数组中包含的每个元素，并返回这些值在一个新的数组，用 NSNull 替换任何 nil 值。也不需要从控制器复制 selectedObjects 数组，因为它是不可变的。

When you call valueForKey: on an array, it calls valueForKey: on each of the elements contained in the array, and returns those values in a new array, substituting NSNull for any nil values. There's also no need to duplicate the selectedObjects array from the controller because it is immutable anyway.

如果你有多个数组控制器所选对象中的对象，并且您想要查看所选对象中所有项目的名称键的值，只需执行：

If you have multiple objects in your array controller's selected objects, and you want to see the value of the name key of all items in the selected objects, simply do:

NSArray *names = [[arrayController selectedObjects] valueForKey:@"name"];

for (id name in names)
    NSLog (@"%@", name);

当然，如果您这样做，您可以立即打印出来：

Of course, you could print them all out at once if you did:

NSLog (@"%@", [[arrayController selectedObjects] valueForKey:@"name"]);

如果 selectedObjects 中只有一个元素，数组，并且调用 valueForKey：，它仍然会返回一个数组，但它将只包含数组中孤立元素的键的值。你可以使用 lastObject 来引用。

If there's only one element in the selectedObjects array, and you call valueForKey:, it will still return an array, but it will only contain the value of the key of the lone element in the array. You can reference this with lastObject.

NSString *theName = [[[arrayController selectedObjects] valueForKey:@"name"] lastObject];
NSLog (@"%@", theName);

这篇关于从NSArray获取字符串值的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！