拉伸和字距调整类型，不能在带有@IBDesignable的Storyboard中工作

Question

这是跟踪/拉伸字体的IBLabel。

它在构建中完美运行。但这些变化并没有在故事板中显示。

// UILabel, but you can set
// the tracking (that's the overall amount of space between all letters)
// and streching (actually squeeze or stretch the letters horizontally)
// Note: it's very common that typographers need you to adjust these.

import UIKit

@IBDesignable
class StyledLabel: UILabel
    {
    @IBInspectable var tracking:CGFloat = 0.8
    // values between about 0.7 to 1.3.  one means normal.

    @IBInspectable var stretching:CGFloat = -0.1
    // values between about -.5 to .5.  zero means normal.

    override func awakeFromNib()
        {
        let ats = NSMutableAttributedString(string: self.text!)
        let rg = NSRange(location: 0, length: self.text!.characters.count)

        ats.addAttribute(
            NSKernAttributeName, value:CGFloat(tracking), range:rg )

        ats.addAttribute(
            NSExpansionAttributeName, value:CGFloat(stretching), range:rg )

        self.attributedText = ats
        }
    }

右侧的模拟器非常完美。

实际上并没有在故事板上显示直播（见左图）。

疯狂猜测，我错过了初始化函数吗？

或者问题是什么？

注意 - 设置字体大小以适合身高：

您可能需要设置字体大小以填充所有设备上的标签框。为了节省你在这里输入的类型，这是一个指向高度＆＃34;，跟踪和拉伸的课程：https://stackoverflow.com/a/37277874/294884

Answer 1

您还应该将代码放在prepareForInterfaceBuilder()中。它仅在界面构建器中调用，而不是在运行时调用。

override func prepareForInterfaceBuilder() {
    let ats = NSMutableAttributedString(string: self.text!)
    let rg = NSRange(location: 0, length: self.text!.characters.count)

    ats.addAttribute(
        NSKernAttributeName, value:CGFloat(tracking), range:rg )

    ats.addAttribute(
        NSExpansionAttributeName, value:CGFloat(stretching), range:rg )

    self.attributedText = ats
}