文字(UITextView)の一部をHyperlink化させる

見返すためにちょこっとメモ
The code in this post is written in Swift 2.3. Sorry for Swift 3.0 users lol
I will convert this to Swift 3.0 soon.

Development Environment

• OS X El Captain 10.11.2
• Xcode Version 8.0

Language

Swift 2.3

Code

ViewController.swift

import UIKit
class ViewController: UIViewController {
    @IBOutlet weak var textView: UITextView!
    var textRange: NSRange = NSRange()

    override func viewDidLoad() {
        super.viewDidLoad()
        setStrings()
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
    }
}
extension ViewController{
    func setStrings(){
        // for Text
        textView.text = "Qiitaに投稿！自分用のメモとして使用しています！"
        textView.userInteractionEnabled = true
        let text = textView.text!
        textView.backgroundColor = UIColor.clearColor()

        let linkText = "Qiita"
        textView.editable = false
        textView.selectable = true
        textView.scrollEnabled = false
        textView.textAlignment = .Center

        let nsTex = text as NSString
        let linkRange = text.rangeOfString(linkText)

        let style = NSMutableParagraphStyle()
        style.alignment = NSTextAlignment.Center

        let attributedString = NSMutableAttributedString(string: text, attributes: [ NSParagraphStyleAttributeName: style ])

        let start = text.startIndex.distanceTo(linkRange!.startIndex)
        let length = linkRange!.startIndex.distanceTo(linkRange!.endIndex)
        textRange = NSMakeRange(start, length)

        /*リンク位置範囲生成*/
        // all text colour
        attributedString.addAttribute(NSForegroundColorAttributeName, value: UIColor.whiteColor(), range: NSMakeRange(0, nsTex.length))
        // link colour
        attributedString.addAttribute(NSForegroundColorAttributeName, value: UIColor.whiteColor(), range: textRange)

        // underline
        attributedString.addAttribute(NSUnderlineStyleAttributeName, value: NSUnderlineStyle.StyleSingle.rawValue, range: textRange)
        textView.attributedText = attributedString
        let tapGes = UITapGestureRecognizer(target: self, action: #selector(ViewController.tapText(_:)))    
        textView.addGestureRecognizer(tapGes)

    func tapText(tap: UITapGestureRecognizer) {
        let location = tap.locationInView(textView)
        let textPosition = textView.closestPositionToPoint(location)
        let selectedPosition = textView.offsetFromPosition(textView.beginningOfDocument, toPosition: textPosition!)
        if NSLocationInRange(selectedPosition, textRange) {
            let url = NSURL(string: "http://qiita.com/")
            if UIApplication.sharedApplication().canOpenURL(url!){
                UIApplication.sharedApplication().openURL(url!)
            }
        }
    }
}