Bold Text in TextView does not work with combination of Spanned and String

Question

I have this code

TextView text1 = (TextView) view.findViewById(R.layout.myLayout);
Spanned myBold = (Html.fromHtml("<b>Test<b>", Html.FROM_HTML_MODE_LEGACY));

If I do

text1.setText(myBold);

Then myBold is in bold,which is ok. But when I want to add a string more, like

text1.setText(myBold+"bla");

Then the whole TextView is not bold anymore. Why does the new String "bla" affect this?

Thanks.

Answer 1

Why does the new String "bla" affect this?

Because what you are really doing is:

text1.setText(myBold.toString() + "bla");

A String has no style information. A Spanned object does.

Use TextUtils.concat() instead:

text1.setText(TextUtils.concat(myBold, "bla"));

Answer 2

A better choice would be to use a Bold StyleSpan . In the next sample only the "hello" world will be set to bold by using such technique:

Java:

final SpannableString caption = new SpannableString("hello world");

// Set to bold from index 0 to the length of 'hello'
caption.setSpan(new StyleSpan(Typeface.BOLD), 0, "hello".length(), Spannable.SPAN_INCLUSIVE_EXCLUSIVE);

yourTextView.setText(caption);
     

Kotlin:

yourTextView.text = SpannableString("hello world").apply {
        // Set to bold from index 0 to the length of 'hello'
        setSpan(StyleSpan(Typeface.BOLD), 0, "hello".length, Spannable.SPAN_INCLUSIVE_EXCLUSIVE))
    }
       

This would be a more optimal solution rather than using the Html.fromHtml technicque, as it doesn't have to go through the overhead of parsing/interpreting the HTML tags. In addition, it allows you to combine more styles, sizes, etc, in the same SpannableString .