是否可以设置自定义字体& NSString的大小?

问题描述

我正在iOS 9中使用Swift.我想为UIAlertAction自定义字体.我在这些问题中搜索了一个迅速的答案:

I'm working with Swift in iOS 9. I want to customize the font for a UIAlertAction. I searched these questions for a Swift answer:

在Swift中更改UIAlertAction的字体

是是否可以在带有iOS8的新XCode中自定义UIAlertController的字体和外观?

对于Objective-C的答案，这个问题是: UIAlertController自定义字体，大小，颜色

And this question for an Objective-C answer:UIAlertController custom font, size, color

但是对于自定义UIAlertAction的字体，没有解决方案.

But there was no solution for customizing the font for a UIAlertAction.

我相信问题是UIAlertAction将NSString用于其title属性. 在Github上查看演示项目.

I believe the problem is that a UIAlertAction uses an NSString for its title property. See demo project on Github.

我想创建一个像这样的字符串:

I would like to create a string like so:

let originalString: String = "OK"
let myString: NSString = originalString as NSString

然后自定义字符串的字体&尺寸.然后，将我的操作添加到警报控制器后，使用键值编码将字符串分配给我的操作:

And then customize the string's font & size. Then after adding my actions to the alert controller, assign the string to my actions using key-value coding:

alertController!.actions[0].setValue(myString, forKey: "title")

但是据我所知，无法为NSString设置自定义字体和大小.如果改用UILabel，则自定义字体很容易.但是我似乎对字符串的局限性感到困惑.有谁知道一种分配自定义字体的方法?大小转换为字符串，还是我相信没有办法做到这一点?

But as far as I can tell, there is no way to set a custom font and size for an NSString. If it used a UILabel instead, then it would be easy to customize the font. But I seem to be stuck with the limitations of strings. Does anyone know a way to assign a custom font & size to a string, or am I correct in believing there is no way to do this?

推荐答案

您将使用NSAttributedString(或其可变的对等物NSMutableAttributedString)来创建包含自定义信息的字符串.由于构造函数采用NSString(在Swift中为String)，因此不会采用NSAttributedString(NSAttributedString不是NSString的子类.).

You would use NSAttributedString (or its mutable counterpart, NSMutableAttributedString) to make a string with custom info. As the constructor takes an NSString (or String in Swift), it will not take an NSAttributedString (NSAttributedString isn't a subclass of NSString.).

您可以使Swift编译器使用unsafeBitCast传递NSAttributedString，但是UIAlertAction可能不喜欢它.

You could fudge the Swift compiler into passing an NSAttributedString using unsafeBitCast, but UIAlertAction may not like it.

查看 UIAlertController自定义字体，大小，颜色，看来您可以使用KVO进行设置.这样做的代码是相似的:

Looking at UIAlertController custom font, size, color, it seems that you can set it using KVO. The code for doing of so is similar:

var alertVC = UIAlertController(title: "Dont care what goes here, since we're about to change below", message: "", preferredStyle: .ActionSheet)
let hogan = NSMutableAttributedString(string: "Presenting the great... Hulk Hogan!")
hogan.addAttribute(NSFontAttributeName, value: UIFont.systemFontOfSize(50), range: NSMakeRange(24, 11))

alertVC.setValue(hogan, forKey: "attributedTitle")

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