title: Explain the meaning of Span flags like SPAN_EXCLUSIVE_EXCLUSIVE
body: <p>Can someone clearly explain with examples what each of the <a href="http://developer.android.com/reference/android/text/Spanned.html">span flags</a> like <code>SPAN_EXCLUSIVE_EXCLUSIVE</code> and <code>SPAN_MARK_MARK</code> mean and when to use what flags?</p>
  
  <p>I do not understand the official documentation when it says:</p>
  
  <blockquote>
    <p>Spans of type <code>SPAN_EXCLUSIVE_EXCLUSIVE</code> do not expand to include text
    inserted at either their starting or ending point.</p>
  </blockquote>
  
  <p>Does "expand to include" refer to edits made after inserting the spans?</p>
  
  <p>Does it mean that these flags do NOT affect Spannables with immutable text?</p>