title: How to merge some spannable objects?
body: <p>I divide a spannable object into 3 parts, do different operations, and then I need to merge them.</p>
  
  <pre><code>Spannable str = editText.getText();
  Spannable selectionSpannable = new SpannableStringBuilder(str, selectionStart, selectionEnd);
  Spannable endOfModifiedSpannable = new SpannableStringBuilder(str, selectionEnd, editText.getText().length());
  Spannable beginningOfModifiedSpannable = new SpannableStringBuilder(str, 0, selectionStart);            
  </code></pre>
  
  <p>How can I do it? I haven't found the required method or constructor to do it.</p>