Displaying HTML Content in Android TextView

In Android development, displaying HTML content in a TextView can be achieved using the Html.fromHtml() method. This method converts the HTML string into a Spanned object, which can then be displayed in a TextView.

To display HTML content in a TextView, you need to pass the HTML string to the Html.fromHtml() method and set the result as the text of the TextView. The basic syntax is as follows:

textView.setText(Html.fromHtml(htmlString));

However, starting from Android N (API level 24), the Html.fromHtml() method has been deprecated in favor of a new version that takes an additional parameter, flags. This parameter specifies how to handle the HTML content.

To display HTML content in a TextView on devices running Android N or later, you should use the following code:

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
    textView.setText(Html.fromHtml(htmlString, Html.FROM_HTML_MODE_COMPACT));
} else {
    textView.setText(Html.fromHtml(htmlString));
}

The Html.FROM_HTML_MODE_COMPACT flag is used to compact the HTML content by removing unnecessary whitespace and line breaks.

In Kotlin, the code would be:

textView.text = if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
    Html.fromHtml(htmlString, Html.FROM_HTML_MODE_COMPACT)
} else {
    Html.fromHtml(htmlString)
}

Note that not all HTML tags are supported by the Html.fromHtml() method. The following tags are supported:

• p
• ul
• ol
• li
• a
• img
• b
• i
• u
• big
• small
• font
• blockquote
• tt
• code
• pre
• hr
• br
• strong
• em

If you need to display more complex HTML content, such as tables or nested lists, you may need to use a WebView instead of a TextView.

Another approach is to create a custom TextView class that automatically converts the text to HTML. This can be done by extending the TextView class and overriding the setText() method:

public class HtmlTextView extends TextView {
    public HtmlTextView(Context context) {
        super(context);
        init();
    }

    public HtmlTextView(Context context, AttributeSet attrs) {
        super(context, attrs);
        init();
    }

    public HtmlTextView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        init();
    }

    private void init() {
        setText(Html.fromHtml(getText().toString()));
    }
}

You can then use this custom TextView in your layout XML file:

<com.example.HtmlTextView
    android:text="@string/your_string" />

This approach allows you to configure the HTML content through XML without modifying the Java code.

If you are trying to display HTML content from a string resource, you may need to use CDATA tags to avoid parsing errors. For example:

<string name="sample_string"><![CDATA[<h2>Title</h2><br><p>Description here</p>]]></string>

You can then display the HTML content using the following code:

textView.setText(Html.fromHtml(getString(R.string.sample_string)));

In conclusion, displaying HTML content in an Android TextView can be achieved using the Html.fromHtml() method. By understanding how to use this method and its limitations, you can create rich text displays in your Android applications.