I would like display for example this html code:
Hello World
This is a test of the URL &
Here's most of the examples. I don't think the pre tag is supported.

This is the strings.xml file:
Formatting
<b>Hello World</b> This is a test of the URL <a href="http://www.example.com/">Example</a>
<b>This text is bold</b>
<em>This text is emphasized</em>
This is <sub>subscript</sub> and <sup>superscript</sup>
Here's the layout. Note for the link to actually be clickable, there's a bit of extra work needed:
Finally, the code:
TextView test1 = (TextView)findViewById(R.id.test1);
Spanned spanned = Html.fromHtml(getString(R.string.link));
test1.setMovementMethod(LinkMovementMethod.getInstance());
test1.setText(spanned);
TextView test2 = (TextView)findViewById(R.id.test2);
test2.setText(Html.fromHtml(getString(R.string.bold)));
TextView test3 = (TextView)findViewById(R.id.test3);
test3.setText(Html.fromHtml(getString(R.string.emphasis)));
TextView test4 = (TextView)findViewById(R.id.test4);
test4.setText(Html.fromHtml(getString(R.string.sup)));