How do I insert special characters as text in XML editor for Android?

Use &lt; for <, &gt; for > and &amp; for &.

or

<   less than   &lt;    
>   greater than    &gt;    
&   ampersand   &amp;   
¢   cent            &cent;  
£   pound           &pound; 
¥   yen         &yen;   
€   euro            &euro;  
§   section         &sect;  
©   copyright   &copy;  
®   registered trademark    &reg;   
™   trademark   &trade;

Try put they as HTML.

String htmlStringWithMathSymbols = "≤  ≥";

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

Here you can display your math symbol in textView

Here the post http://www.hrupin.com/2011/12/how-to-put-some-special-math-symbols-in-textview-editview-or-other-android-ui-element

Hope, it help you!