License: Apache-2.0

MyHtmlTextView.kt

package com.example.app

import android.content.Context
import android.text.Html
import android.text.SpannableString
import android.text.Spanned
import android.text.style.URLSpan
import android.text.util.Linkify
import android.util.AttributeSet
import org.sufficientlysecure.htmltextview.*
import java.lang.reflect.Field
import java.lang.reflect.Method
import android.util.Log
import android.view.View

// Waiting on https://github.com/PrivacyApps/html-textview/issues/87
//   (I'd rather not fork the library, or include it in the project)

class MyHtmlTextView @JvmOverloads constructor(
        context: Context, attrs: AttributeSet? = null, defStyleAttr: Int = 0
) : HtmlTextView(context, attrs, defStyleAttr) {
    // Callback
    var onLinkClicked: ((String) -> Boolean)? = null

    //
    // Expose private members and methods  :(
    //

    companion object {
        private val clickableTableSpanField:  Field = HtmlTextView::class.java.getDeclaredField("clickableTableSpan")
        private val drawTableLinkSpanField:   Field = HtmlTextView::class.java.getDeclaredField("drawTableLinkSpan")
        private val removeFromHtmlSpaceField: Field = HtmlTextView::class.java.getDeclaredField("removeFromHtmlSpace")

        private val removeHtmlBottomPaddingMethod: Method = HtmlTextView::class.java.getDeclaredMethod("removeHtmlBottomPadding", CharSequence::class.java)
    }

    init {
        clickableTableSpanField.isAccessible       = true
        drawTableLinkSpanField.isAccessible        = true
        removeFromHtmlSpaceField.isAccessible      = true
        removeHtmlBottomPaddingMethod.isAccessible = true
    }

    private val clickableTableSpan
            get() = clickableTableSpanField.get(this) as ClickableTableSpan?

    private val drawTableLinkSpan
            get() = drawTableLinkSpanField.get(this) as DrawTableLinkSpan?

    private val removeFromHtmlSpace
            get() = removeFromHtmlSpaceField.get(this) as Boolean

    private fun removeHtmlBottomPadding(text: CharSequence?): CharSequence? =
            removeHtmlBottomPaddingMethod.invoke(null, text) as CharSequence?

    private fun callOverrideTagsMethod(htmlTagHandler: HtmlTagHandler, html: String): String {
        val overrideTagsMethod = htmlTagHandler::class.java.getDeclaredMethod("overrideTags", String::class.java)
        overrideTagsMethod.isAccessible = true
        return overrideTagsMethod.invoke(htmlTagHandler, html) as String
    }


    //
    // Override function
    //

    override fun setHtml(html: String, imageGetter: Html.ImageGetter?) {
        val htmlTagHandler = HtmlTagHandler(paint)
        htmlTagHandler.setClickableTableSpan(clickableTableSpan)
        htmlTagHandler.setDrawTableLinkSpan(drawTableLinkSpan)
        val htmlCorrected = callOverrideTagsMethod(htmlTagHandler, html)

        val spans =
                if (removeFromHtmlSpace) {
                    removeHtmlBottomPadding(Html.fromHtml(htmlCorrected, imageGetter, htmlTagHandler)) as Spanned
                } else {
                    Html.fromHtml(htmlCorrected, imageGetter, htmlTagHandler)
                }

        text = addLinkCallbacksToSpanned(spans)

        // make links work
        movementMethod = LocalLinkMovementMethod.getInstance()
    }

    private fun addLinkCallbacksToSpanned(text: Spanned): Spanned {
        val buffer = SpannableString(text)

        Linkify.addLinks(buffer, Linkify.WEB_URLS)

        val spans = text.getSpans(0, text.length, URLSpan::class.java) as Array<URLSpan>
        for (us in spans) {
            val url = us.url
            val end = text.getSpanEnd(us) //Getting the spans position
            val start = text.getSpanStart(us)
            
            buffer.setSpan(object : URLSpan(us.url) { // A new span with the same URL
                override fun onClick(widget: View) {
                    if (onLinkClicked?.invoke(url) != true) {
                        super.onClick(widget)
                    }
                }
            }, start, end, 0) //Overwriting the old span
        }

        return buffer
    }

}