[英]Objective C & Swift Interoperability causes error “Extensions may not contain stored properties”
I was working on one of my previous app that was done on Objective C. I need to add a new module to it and I decided to use Swift for that particular module. 我正在研究我在Objective C上完成的一个应用程序。我需要为它添加一个新模块,我决定将Swift用于该特定模块。
I have a class called HomePage
in Objective C, I wanted to add some new IBAction
s and IBOutlet
s in it. 我在Objective C中有一个名为
HomePage
的类,我想在其中添加一些新的IBAction
和IBOutlet
。 For that I added a new swift file and extended the existing class like: 为此我添加了一个新的swift文件并扩展了现有的类,如:
// MARK: IBOutlets and IBActions
extension HomePage
{
@IBOutlet var image : UIImageView!
...
/*!
* Loads the application support webpage
*/
@IBAction func loadSupportURL(sender : UIButton)
{
}
...
}
If I add only the IBActions everything is working perfectly. 如果我只添加IBActions,一切都很完美。 But when I add an IBOutlet, the compiler throws an error like:
但是当我添加一个IBOutlet时,编译器会抛出一个错误:
Extensions may not contain stored properties
扩展名可能不包含存储的属性
For fixing it I have two ways, 为了解决这个问题,我有两种方法,
Is there any other way to fix this issue ? 有没有其他方法可以解决这个问题?
As the error message clearly states, you can't have stored properties in an extension. 正如错误消息明确指出的那样,您不能在扩展中存储属性。 But the thing is, you can't have them in Objective-C categories either, so the language isn't the problem here.
但问题是,你不能在Objective-C类别中使用它们,所以这里的语言不是问题。
In both languages, you need to use associated references to implement stored properties. 在这两种语言中,您需要使用关联的引用来实现存储的属性。 Please see this thread for an example of using associated references in Swift.
有关在Swift中使用关联引用的示例,请参阅此主题 。 Since it is a C API, its usage is pretty much the same in Objective-C.
由于它是一个C API,它在Objective-C中的用法几乎相同。
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.