Spannable Click

MainActivity.kt

package com.codangcoding.spannable

import android.os.Bundle
import android.support.v7.app.AppCompatActivity
import android.text.Html
import android.text.SpannableStringBuilder
import android.text.method.LinkMovementMethod
import android.text.style.URLSpan
import android.view.View
import android.widget.Toast
import kotlinx.android.synthetic.main.activity_main.*

class MainActivity : AppCompatActivity() {
    private val htmlContent = """
<div id="toc" class="toc">
    <div class="toctitle" lang="en" dir="ltr">
        <h2>Contents</h2>
        <span class="toctoggle">&nbsp;[<a role="button" tabindex="0" class="togglelink">hide</a>]&nbsp;</span>
    </div>
    <ul>
        <li class="toclevel-1 tocsection-1"><a href="#Characteristics"><span
                class="tocnumber">1</span> <span class="toctext">Characteristics</span></a>
            <ul>
                <li class="toclevel-2 tocsection-2"><a href="#Editing"><span
                        class="tocnumber">1.1</span> <span class="toctext">Editing</span></a></li>
                <li class="toclevel-2 tocsection-3"><a href="#Navigation"><span class="tocnumber">1.2</span>
                    <span class="toctext">Navigation</span></a></li>
                <li class="toclevel-2 tocsection-4"><a href="#Linking_and_creating_pages"><span
                        class="tocnumber">1.3</span> <span class="toctext">Linking and creating pages</span></a>
                </li>
                <li class="toclevel-2 tocsection-5"><a href="#Searching"><span
                        class="tocnumber">1.4</span> <span class="toctext">Searching</span></a></li>
            </ul>
        </li>
        <li class="toclevel-1 tocsection-6"><a href="#History"><span class="tocnumber">2</span>
            <span class="toctext">History</span></a></li>
        <li class="toclevel-1 tocsection-7"><a href="#Alternative_definitions"><span
                class="tocnumber">3</span> <span class="toctext">Alternative definitions</span></a>
        </li>
        <li class="toclevel-1 tocsection-8"><a href="#Implementations"><span
                class="tocnumber">4</span> <span class="toctext">Implementations</span></a></li>
        <li class="toclevel-1 tocsection-9"><a href="#Trust_and_security"><span
                class="tocnumber">5</span> <span class="toctext">Trust and security</span></a>
            <ul>
                <li class="toclevel-2 tocsection-10"><a href="#Controlling_changes"><span
                        class="tocnumber">5.1</span> <span
                        class="toctext">Controlling changes</span></a></li>
                <li class="toclevel-2 tocsection-11"><a
                        href="#Trustworthiness_and_reliability_of_content"><span class="tocnumber">5.2</span>
                    <span class="toctext">Trustworthiness and reliability of content</span></a></li>
                <li class="toclevel-2 tocsection-12"><a href="#Security"><span
                        class="tocnumber">5.3</span> <span class="toctext">Security</span></a>
                    <ul>
                        <li class="toclevel-3 tocsection-13"><a
                                href="#Potential_malware_vector"><span
                                class="tocnumber">5.3.1</span> <span class="toctext">Potential malware vector</span></a>
                        </li>
                    </ul>
                </li>
            </ul>
        </li>
        <li class="toclevel-1 tocsection-14"><a href="#Communities"><span class="tocnumber">6</span>
            <span class="toctext">Communities</span></a>
            <ul>
                <li class="toclevel-2 tocsection-15"><a href="#Applications"><span
                        class="tocnumber">6.1</span> <span class="toctext">Applications</span></a>
                </li>
                <li class="toclevel-2 tocsection-16"><a href="#City_wikis"><span class="tocnumber">6.2</span>
                    <span class="toctext">City wikis</span></a></li>
                <li class="toclevel-2 tocsection-17"><a href="#WikiNodes"><span class="tocnumber">6.3</span>
                    <span class="toctext">WikiNodes</span></a></li>
                <li class="toclevel-2 tocsection-18"><a href="#Participants"><span
                        class="tocnumber">6.4</span> <span class="toctext">Participants</span></a>
                </li>
                <li class="toclevel-2 tocsection-19"><a href="#Growth_factors"><span
                        class="tocnumber">6.5</span> <span class="toctext">Growth factors</span></a>
                </li>
            </ul>
        </li>
        <li class="toclevel-1 tocsection-20"><a href="#Conferences"><span class="tocnumber">7</span>
            <span class="toctext">Conferences</span></a></li>
        <li class="toclevel-1 tocsection-21"><a href="#Rules"><span class="tocnumber">8</span> <span
                class="toctext">Rules</span></a></li>
        <li class="toclevel-1 tocsection-22"><a href="#Legal_environment"><span
                class="tocnumber">9</span> <span class="toctext">Legal environment</span></a></li>
        <li class="toclevel-1 tocsection-23"><a href="#See_also"><span class="tocnumber">10</span>
            <span class="toctext">See also</span></a></li>
        <li class="toclevel-1 tocsection-24"><a href="#Notes"><span class="tocnumber">11</span>
            <span class="toctext">Notes</span></a></li>
        <li class="toclevel-1 tocsection-25"><a href="#References"><span class="tocnumber">12</span>
            <span class="toctext">References</span></a></li>
        <li class="toclevel-1 tocsection-26"><a href="#Further_reading"><span
                class="tocnumber">13</span> <span class="toctext">Further reading</span></a></li>
        <li class="toclevel-1 tocsection-27"><a href="#External_links"><span
                class="tocnumber">14</span> <span class="toctext">External links</span></a></li>
    </ul>
</div>
    """.trimIndent()

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        val spannableString = SpannableStringBuilder(Html.fromHtml(htmlContent))
        spannableString
            .getSpans(0, spannableString.length, URLSpan::class.java)
            .forEach { span ->
                val start = spannableString.getSpanStart(span)
                val end = spannableString.getSpanEnd(span)

                spannableString.removeSpan(span)
                spannableString.setSpan(object : URLSpan(span.url) {
                    override fun onClick(widget: View?) {
                        Toast.makeText(this@MainActivity, url, Toast.LENGTH_SHORT).show()
                    }
                }, start, end, 0)
            }
        tv_html.movementMethod = LinkMovementMethod.getInstance()
        tv_html.text = spannableString
    }
}