messageLabel
messageLabel
On clicking "Read more" button increase height constraint constant, on clicking "Read less" decrease height constraint constant.
@IBOutlet weak var btn: UIButton!
@IBOutlet weak var lblHeight: NSLayoutConstraint!
var isLabelAtMaxHeight = false
@IBAction func btnAction(_ sender: Any) {
if isLabelAtMaxHeight {
btn.setTitle("Read more", for: .normal)
isLabelAtMaxHeight = false
lblHeight.constant = 70
}
else {
btn.setTitle("Read less", for: .normal)
isLabelAtMaxHeight = true
lblHeight.constant = getLabelHeight(text: yourSummaryText, width: view.bounds.width, font: yourSummaryLabel.font)
}
}
获取文本的高度
func getLabelHeight(text: String, width: CGFloat, font: UIFont) -> CGFloat {
let lbl = UILabel(frame: .zero)
lbl.frame.size.width = width
lbl.font = font
lbl.numberOfLines = 0
lbl.text = text
lbl.sizeToFit()
return lbl.frame.size.height
}
我已经通过修剪字符串完成了它。
我们可以通过.count比较字符串字符长度,如果字符串中只有很少的字符,我们可以隐藏“阅读更多”按钮。
并在修剪后删除最后一个单词,以确保没有可见的单词被切断。然后在末尾添加“....”
var trimData = ""
if eventData.eventDescription.count > 500 {
cell.readMoreLabel.isHidden = false
if !readMore {
if eventData.eventDescription.count > 500 {
trimData = String(eventData.eventDescription.prefix(500))
trimData = trimData.components(separatedBy: " ").dropLast().joined(separator: " ")
trimData = trimData+"...."
} else {
trimData = eventData.eventDescription
}
cell.readMoreLabel.attributedText = NSAttributedString(string: "Read More", attributes:
[.underlineStyle: NSUnderlineStyle.styleSingle.rawValue])
} else {
trimData = eventData.eventDescription
cell.readMoreLabel.attributedText = NSAttributedString(string: "Read Less", attributes:
[.underlineStyle: NSUnderlineStyle.styleSingle.rawValue])
}
} else {
trimData = eventData.eventDescription
cell.readMoreLabel.isHidden = true
}