使用 swift 在 xcode 6 中自定义 NSValueTransformer [英] Custom NSValueTransformer in xcode 6 with swift
问题描述
有没有人在 xcode 6 beta 中使用 swift 成功实现自定义 NSValueTransformer?
Did anyone successfully implement a custom NSValueTransformer in xcode 6 beta with swift?
我有以下 swift 类:
I have the following swift class:
import Foundation
class myTransformer: NSValueTransformer {
let amount = 100
override class func transformedValueClass() -> AnyClass!
{
return NSNumber.self
}
override func transformedValue(value: AnyObject!) -> AnyObject! {
return value.integerValue + amount
}
}
所以这个转换器应该做的就是将 100 添加到 gui 中的给定值.
So all this transformer should do is, adding 100 to a given value in the gui.
如您所见,转换器类现在出现在 IB 的 Value Transformer 下拉列表中.
As you can see, the transformer class appears now in the Value Transformer drop down in IB.
但是如果我选择这个转换器,应用程序就会崩溃:
But if I choose this transformer the application crashes with:
2014-08-27 20:12:17.686 cdTest[44134:303]
*** Terminating app due to uncaught exception 'NSInternalInconsistencyException',
reason: 'Cannot find value transformer with name newTransformer'
在 AppDelegate 中注册这个转换器是否正确
Is it right to register this transformer in the AppDelegate with
override class func initialize() {
let newTransformer = myTransformer()
}
有人知道这一切应该如何运作吗?
Does anyone know how this whole stuff should work?
亲切的问候!马丁
推荐答案
在您初始化 newTransformer 之后,您还应该包括以下行:
After you initialise newTransformer you should also include the line:
NSValueTransformer.setValueTransformer(newTransformer, forName: "myTransformer")
然后在您的 Interface Builder 中,您应该在 Value Transformer 下拉菜单下使用 myTransformer 而不是 newTransformer.
Then in your Interface Builder you should use myTransformer instead of newTransformer under the Value Transformer dropdown.
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