如何在 swift 中为选框/滚动文本效果制作一个简单的 UILabel 子类?

Question

正如你在上面看到的，我试图编写UILabel的简单(！)子类，以便在标签的文本太长时制作选框或滚动文本效果。我知道已经有很好的课程了(例如 https://cocoapods.org/pods/MarqueeLabel)，但我想自己做:)

在下面你可以看到我目前的班级。 我也无法解决新标签向右滚动的问题，但还有第三个标签不应该存在。我认为这是标签本身。但是当我尝试用该标签替换第一个附加标签时，我将不起作用。我希望它不会太混乱：/

对我来说，重要的是我只需要将故事板中的类分配给标签。这样就不需要去添加代码，例如在视图控制器中(在插座旁边)。我希望清楚我想要什么:D

所以再说一遍：

• UILabel的简单子类
• 滚动标签
• 应该在其他类中无需任何其他代码即可工作(例如,...更改标签文本的插座除外)

(这是我自己的第一个子类，所以请随时教我如何正确:))

谢谢！

到目前为止，它并不完美，但这是我目前的课程：

import UIKit
class LoopLabel: UILabel {
var labelText : String?
var rect0: CGRect!
var rect1: CGRect!
var labelArray = [UILabel]()
var isStop = false
var timeInterval: TimeInterval!
let leadingBuffer = CGFloat(25.0)
let loopStartDelay = 2.0
required public init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
self.lineBreakMode = .byClipping
}
override var text: String? {
didSet {
labelText = text
setup()
}
}
func setup() {
let label = UILabel()
label.frame = CGRect.zero
label.text = labelText
timeInterval = TimeInterval((labelText?.characters.count)! / 5)
let sizeOfText = label.sizeThatFits(CGSize.zero)
let textIsTooLong = sizeOfText.width > frame.size.width ? true : false
rect0 = CGRect(x: leadingBuffer, y: 0, width: sizeOfText.width, height: self.bounds.size.height)
rect1 = CGRect(x: rect0.origin.x + rect0.size.width, y: 0, width: sizeOfText.width, height: self.bounds.size.height)
label.frame = rect0
super.clipsToBounds = true
labelArray.append(label)
self.addSubview(label)
self.frame = CGRect(origin: self.frame.origin, size: CGSize(width: 0, height: 0))
if textIsTooLong {
let additionalLabel = UILabel(frame: rect1)
additionalLabel.text = labelText
self.addSubview(additionalLabel)
labelArray.append(additionalLabel)
animateLabelText()
}
}
func animateLabelText() {
if(!isStop) {
let labelAtIndex0 = labelArray[0]
let labelAtIndex1 = labelArray[1]
UIView.animate(withDuration: timeInterval, delay: loopStartDelay, options: [.curveLinear], animations: {
labelAtIndex0.frame = CGRect(x: -self.rect0.size.width,y: 0,width: self.rect0.size.width,height: self.rect0.size.height)
labelAtIndex1.frame = CGRect(x: labelAtIndex0.frame.origin.x + labelAtIndex0.frame.size.width,y: 0,width: labelAtIndex1.frame.size.width,height: labelAtIndex1.frame.size.height)
}, completion: { finishied in
labelAtIndex0.frame = self.rect1
labelAtIndex1.frame = self.rect0
self.labelArray[0] = labelAtIndex1
self.labelArray[1] = labelAtIndex0
self.animateLabelText()
})
} else {
self.layer.removeAllAnimations()
}
}
}

Answer 1

首先，如果您不需要在外部访问变量，尤其是 labelText(因为您正在使用要设置的计算属性文本)，我会将变量保密。

其次，由于您要添加标签作为子视图，因此我宁愿使用 UIView 作为容器而不是 UILabel。情节提要中的唯一区别是添加视图而不是标签。

第三，如果使用此方法，则不应将(视图的)框架设置为零。

类似这样的事情就可以了：

import UIKit
class LoopLabelView: UIView {
private var labelText : String?
private var rect0: CGRect!
private var rect1: CGRect!
private var labelArray = [UILabel]()
private var isStop = false
private var timeInterval: TimeInterval!
private let leadingBuffer = CGFloat(25.0)
private let loopStartDelay = 2.0
required public init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
}
var text: String? {
didSet {
labelText = text
setup()
}
}
func setup() {
self.backgroundColor = UIColor.yellow
let label = UILabel()
label.text = labelText
label.frame = CGRect.zero
timeInterval = TimeInterval((labelText?.characters.count)! / 5)
let sizeOfText = label.sizeThatFits(CGSize.zero)
let textIsTooLong = sizeOfText.width > frame.size.width ? true : false
rect0 = CGRect(x: leadingBuffer, y: 0, width: sizeOfText.width, height: self.bounds.size.height)
rect1 = CGRect(x: rect0.origin.x + rect0.size.width, y: 0, width: sizeOfText.width, height: self.bounds.size.height)
label.frame = rect0
super.clipsToBounds = true
labelArray.append(label)
self.addSubview(label)
//self.frame = CGRect(origin: self.frame.origin, size: CGSize(width: 0, height: 0))
if textIsTooLong {
let additionalLabel = UILabel(frame: rect1)
additionalLabel.text = labelText
self.addSubview(additionalLabel)
labelArray.append(additionalLabel)
animateLabelText()
}
}
func animateLabelText() {
if(!isStop) {
let labelAtIndex0 = labelArray[0]
let labelAtIndex1 = labelArray[1]
UIView.animate(withDuration: timeInterval, delay: loopStartDelay, options: [.curveLinear], animations: {
labelAtIndex0.frame = CGRect(x: -self.rect0.size.width,y: 0,width: self.rect0.size.width,height: self.rect0.size.height)
labelAtIndex1.frame = CGRect(x: labelAtIndex0.frame.origin.x + labelAtIndex0.frame.size.width,y: 0,width: labelAtIndex1.frame.size.width,height: labelAtIndex1.frame.size.height)
}, completion: { finishied in
labelAtIndex0.frame = self.rect1
labelAtIndex1.frame = self.rect0
self.labelArray[0] = labelAtIndex1
self.labelArray[1] = labelAtIndex0
self.animateLabelText()
})
} else {
self.layer.removeAllAnimations()
}
}
}