android kotlin - TextView add Hyperlink programmatically

This code demonstrates how to programmatically add a hyperlink to a TextView text in an Android application.

The code first defines a string variable htmlString that contains HTML code for the desired text with a hyperlink. The <a> tag is used to define the hyperlink, with the href attribute specifying the URL of the link.

Next, the code uses the HtmlCompat.fromHtml() function to convert the HTML string into a Spanned object. The Spanned object is an interface that represents text that can have different styles applied to different parts. In this case, the Spanned object will contain the text with the hyperlink styled appropriately.

The code then sets the movementMethod property of the TextView to a LinkMovementMethod object. The LinkMovementMethod class is responsible for handling link clicks in TextView widgets. When the user clicks on a part of the text that is formatted as a hyperlink, the LinkMovementMethod will handle the click and launch the web browser to open the linked URL.

Finally, the code sets the text of the TextView to the Spanned object that was created from the HTML string. This displays the text with the hyperlink in the TextView.

In summary,

The code creates a TextView with a hyperlink. Clicking the hyperlink will launch the web browser and open the linked URL.

Here is a table summarizing the steps involved in adding a hyperlink to a TextView text programmatically:

Step	Description
1	Define a string variable containing HTML code for the desired text with a hyperlink.
2	Use the `HtmlCompat.fromHtml()` function to convert the HTML string into a `Spanned` object.
3	Set the `movementMethod` property of the TextView to a `LinkMovementMethod` object.
4	Set the text of the TextView to the `Spanned` object that was created from the HTML string.

MainActivity.kt


package com.example.jetpack

import android.os.Bundle
import android.text.method.LinkMovementMethod
import androidx.appcompat.app.AppCompatActivity
import androidx.core.text.HtmlCompat
import kotlinx.android.synthetic.main.activity_main.*


class MainActivity : AppCompatActivity() {

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

        // string inside html markup objects
        val htmlString = "Hyperlink inside TextView.<br />" +
                "<a href='https://developer.android.com/'>developer.android.com</a>"

        // spanned is the interface for text that has
        // markup objects attached to ranges of it
        val spanned = HtmlCompat.fromHtml(
            htmlString, // source
            HtmlCompat.FROM_HTML_MODE_LEGACY // flags
        )

        // LinkMovementMethod traverses links in the text buffer and scrolls
        // if necessary. Supports clicking on links with DPad Center or Enter.
        textView.movementMethod = LinkMovementMethod.getInstance()

        // finally, show text view text with html hyperlink
        textView.text = spanned
    }
}

activity_main.xml


<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/constraintLayout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#EDEAE0"
    tools:context=".MainActivity">

    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:padding="25dp"
        android:textSize="30sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        tools:text="TextView" />

</androidx.constraintlayout.widget.ConstraintLayout>