对我正在开发的应用程序进行一些基本改进。对于 iOS 快速开发场景来说还是个新手。我认为代码中的文本行会自动居中,因为我将标签设置为居中。经过一番研究后,我发现事实并非如此。我如何将这样的代码对齐到中心:
let atrString = try NSAttributedString(
data: assetDetails!.cardDescription.dataUsingEncoding(NSUTF8StringEncoding)!,
options: [NSDocumentTypeDocumentAttribute:NSHTMLTextDocumentType],
documentAttributes: nil)
assetDescription.attributedText = atrString
您需要创建指定居中对齐的段落样式,并将该段落样式设置为文本的属性。游乐场示例:
import UIKit
import PlaygroundSupport
let style = NSMutableParagraphStyle()
style.alignment = NSTextAlignment.center
let richText = NSMutableAttributedString(string: "Going through some basic improvements to a application I am working on. Still new to the iOS swift development scene. I figured that the lines of text in my code would automatically be centered because I set the label to center.",
attributes: [ NSParagraphStyleAttributeName: style ])
// In Swift 4, use `.paragraphStyle` instead of `NSParagraphStyleAttributeName`.
let label = UILabel(frame: CGRect(x: 0, y: 0, width: 200, height: 400))
label.backgroundColor = UIColor.white
label.attributedText = richText
label.numberOfLines = 0
PlaygroundPage.current.liveView = label
结果:
由于您正在解析 HTML 文档来创建属性字符串,因此您需要在创建后添加属性,如下所示:
let style = NSMutableParagraphStyle()
style.alignment = NSTextAlignment.center
let richText = try NSMutableAttributedString(
data: assetDetails!.cardDescription.data(using: String.Encoding.utf8)!,
options: [NSDocumentTypeDocumentAttribute:NSHTMLTextDocumentType],
documentAttributes: nil)
richText.addAttributes([ NSParagraphStyleAttributeName: style ],
range: NSMakeRange(0, richText.length))
// In Swift 4, use `.paragraphStyle` instead of `NSParagraphStyleAttributeName`.
assetDescription.attributedText = richText
在 Swift 4 中,属性名称现在为
NSAttributeStringKey
类型,标准属性名称是该类型的静态成员。所以你可以像这样添加属性:
richText.addAttribute(.paragraphStyle, value: style, range: NSMakeRange(0, richText.length))
在 Swift 4.1 中:
let style = NSMutableParagraphStyle()
style.alignment = NSTextAlignment.center
lbl.centerAttributedText = NSAttributedString(string: "Total Balance",attributes: [.paragraphStyle: style])
(编辑代码块)
您可以使用此实用功能对标签进行所有常见配置
@discardableResult
public func DULabel(text: String, frame: CGRect = .zero, parent:UIView? = nil , font:UIFont, textColor:UIColor = .black, numOfLines:Int = 0 ,textAlignment: NSTextAlignment = .center,lineSpaceing:CGFloat = 0, cb: ((UILabel)->Void)? = nil )-> UILabel! {
let label = UILabel()
label.frame = frame
label.font = font
label.textColor = textColor
label.textAlignment = textAlignment
label.numberOfLines = numOfLines
if( lineSpaceing == 0 ){
label.text = text
}
else {
let paragraphStyle = NSMutableParagraphStyle()
paragraphStyle.lineSpacing = lineSpaceing
paragraphStyle.alignment = textAlignment
let attrString = NSMutableAttributedString(string: text)
attrString.addAttribute(.paragraphStyle, value:paragraphStyle, range:NSMakeRange(0, attrString.length))
label.attributedText = attrString
}
if let parent = parent {
parent.addSubview(label)
}
cb?(label)
return label
}
该代码用于创建指定居中对齐的段落样式,并将该段落样式设置为文本的属性。
let style = NSMutableParagraphStyle()
style.alignment = NSTextAlignment.center
lblParagraph.centerAttributedText = NSAttributedString(string: "Your Label",attributes: [.paragraphStyle: style])