最近在做一個練習(xí)項(xiàng)目的時候，經(jīng)常寫到要設(shè)置富文本屬性的地方，所以寫了一個簡單的封裝，因?yàn)閟wift的字符下標(biāo)采用的是string.index的類型，而富文本熟悉設(shè)置是原有的Range(Int, Int)類型。所以在將字符的string.index轉(zhuǎn)為Int這方面耗費(fèi)了不少功夫，最終也還是沒有找到直接轉(zhuǎn)換的方法。而是通過截取string.index的內(nèi)容來獲取相對應(yīng)的Int下標(biāo)。雖然是挺非主流的方法，但是本人親測有效。另外如果你有更好的string.index轉(zhuǎn)Int下標(biāo)的方法，歡迎分享，當(dāng)然是在swift3.0的環(huán)境下，哈哈。

• 結(jié)果

  
  
  屏幕快照 2017-03-23 下午1.50.01.png
• 調(diào)用示例

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        let lbl = UILabel.init(with: "", textColor: UIColor.black, fontSize: 15)
        let originString = "周末閑著無聊，想起最近遇到一個關(guān)于文字顯示設(shè)置的小問題，想著以后可能還會經(jīng)常用到，所以趁這個時候一起整理一下，方便以后備用"
        //初始化一個CHAttributeStringTool對象
        let ch = CHAttributeStringTool.init(withString: originString)
        //設(shè)置富文本屬性，注：屬性可以疊加，from：起始字符，傳""表示從第一個字符；to：截止字符，傳""表示到最后一個字符
        ch.set(strikeLineColor: UIColor.red, lineSize: 5, from: "想著以后", to: "用到")
        //賦值富文本屬性
        lbl.attributedText = ch.chString
        lbl.frame = CGRect(x: (UIScreen.main.bounds.size.width - 200)/2, y: 100, width: 200, height: 300)
        lbl.numberOfLines = 0
        self.view.addSubview(lbl)
        
    }
}
//MARK: - UIlabel
extension UILabel {
    convenience init(with text: String, textColor: UIColor,fontSize: CGFloat) {
        self.init()
        self.text = text
        self.font = UIFont.systemFont(ofSize: fontSize)
        self.textColor = textColor
    }
}

• 以下是封裝代碼，有用的話直接拷走就行啦，然后記得給個贊哈哈哈

import UIKit
class CHAttributeStringTool: NSObject {
    //MARK: - 內(nèi)部屬性
    private var originString: String?
    private var characterCount: Int = 0
    private var style = NSMutableParagraphStyle()
    private var range: NSRange?
    //MARK: - 外部屬性
    public var chString: NSMutableAttributedString?
    
    //MARK: - 外部方法
    init(withString str: String) {
        originString = str
        characterCount = str.characters.count
        chString = NSMutableAttributedString.init(string: str)
    }
    ///設(shè)置刪除線
    public func set(strikeLineColor lineColor: UIColor,lineSize: Float, from: String, to: String) {
        let range = calculRange(withString: originString!, from: from, to: to)
        chString?.addAttributes([NSStrikethroughStyleAttributeName: lineSize], range: range)
        chString?.addAttributes([NSStrikethroughColorAttributeName: lineColor], range: range)
    }
    ///設(shè)置下劃線
    public func set(underLineColor lineColor: UIColor, lineSize: Float, from: String, to: String) {
        let range = calculRange(withString: originString!, from: from, to: to)
        chString?.addAttributes([NSUnderlineStyleAttributeName: lineSize], range: range)
        chString?.addAttributes([NSUnderlineColorAttributeName: lineColor], range: range)
    }
    ///設(shè)置字體傾斜
    public func set(Obliqueness size: CGFloat, from: String, to: String) {
        let range = calculRange(withString: originString!, from: from, to: to)
        chString?.addAttributes([NSObliquenessAttributeName: size], range: range)
    }
    ///設(shè)置字距
    public func set(stringSpacing: Float, from: String, to: String) {
        let range = calculRange(withString: originString!, from: from, to: to)
        chString?.addAttributes([NSKernAttributeName: stringSpacing], range: range)
    }
    ///設(shè)置字號
    public func set(fontSize: CGFloat, from: String, to: String) {
        let range = calculRange(withString: originString!, from: from, to: to)
        chString?.addAttributes([NSFontAttributeName: UIFont.systemFont(ofSize: fontSize)], range: range)
    }
    ///設(shè)置粗體字號
    public func set(boldFontSize: CGFloat, from: String, to: String) {
        let range = calculRange(withString: originString!, from: from, to: to)
        chString?.addAttributes([NSFontAttributeName: UIFont.boldSystemFont(ofSize: boldFontSize)], range: range)
    }
    ///設(shè)置前景色
    public func set(foregroundColor color: UIColor, from: String, to: String) {
        let range = calculRange(withString: originString!, from: from, to: to)
        chString?.addAttributes([NSForegroundColorAttributeName: color], range: range)
    }
    ///設(shè)置背景色
    public func set(backgroundColor color: UIColor, from: String, to: String) {
        let range = calculRange(withString: originString!, from: from, to: to)
        chString?.addAttributes([NSBackgroundColorAttributeName: color], range: range)
    }
    
    ///段落屬性相關(guān)
    ///設(shè)置行間距
    public func set(lineSpacing: CGFloat) {
        let range = calculRange(withString: originString!, from: "", to: "")
        style.lineSpacing = lineSpacing
        chString?.addAttributes([NSParagraphStyleAttributeName: style], range: range)
    }
    ///設(shè)置首行縮進(jìn)距離
    public func set(firstLineIndent indent : CGFloat) {
        let range = calculRange(withString: originString!, from: "", to: "")
        style.firstLineHeadIndent = indent
        chString?.addAttributes([NSParagraphStyleAttributeName: style], range: range)
    }
    ///設(shè)置每行行首縮進(jìn)距離
    public func set(headerIndent indent: CGFloat) {
        let range = calculRange(withString: originString!, from: "", to: "")
        style.headIndent = indent
        chString?.addAttributes([NSParagraphStyleAttributeName: style], range: range)
    }
    ///設(shè)置每行行末縮進(jìn)距離
    public func set(tailIndent indent: CGFloat) {
        let range = calculRange(withString: originString!, from: "", to: "")
        style.tailIndent = -indent
        chString?.addAttributes([NSParagraphStyleAttributeName: style], range: range)
    }
    ///設(shè)置文本對齊
    public func set(textAlignment alignment: NSTextAlignment) {
        let range = calculRange(withString: originString!, from: "", to: "")
        style.alignment = alignment
        chString?.addAttributes([NSParagraphStyleAttributeName: style], range: range)
    }
    
    //MARK: - 內(nèi)部方法
    ///計(jì)算range
    private func calculRange(withString originStr:String, from: String, to: String)-> NSRange {
        var loc1 = 0
        var loc2 = 0
        loc1 = from == "" ? 0 : stringIndexToInt(withString: originStr, calculString: from).start
        loc2 = to == "" ? characterCount : stringIndexToInt(withString: originStr, calculString: to).end
        return NSMakeRange(loc1, loc2 - loc1)
    }
    
    ///string.index轉(zhuǎn)Int
    private func stringIndexToInt(withString originString: String, calculString: String)-> (start: Int, end: Int) {
        let range = originString.range(of: calculString)
        if range == nil {
            print("originString中不包含calculString")
            return (0,0)
        }
        let rangeStr = String(describing: range?.lowerBound)
        print(rangeStr.characters)
        
        let positionRange1 = rangeStr.range(of: "_position: ")
        let positionRange2 = rangeStr.range(of: ")")
        print(rangeStr)
        let str = rangeStr.substring(with: ((positionRange1?.upperBound)!..<(positionRange2?.lowerBound)!))
        
        let rangeStr2 = String.init(describing: range?.upperBound)
        print(rangeStr2)
        let positionRange3 = rangeStr2.range(of: "_position: ")
        let positionRange4 = rangeStr2.range(of: ")")
        let str2 = rangeStr2.substring(with: ((positionRange3?.upperBound)!..<(positionRange4?.lowerBound)!))
        print(str2)
        let result = (start: Int(str)!, end: Int(str2)!)
        return result
    }
}