title: Change DecimalFormat locale
body: <p>I have custom <code>DecimalFormat</code> in Edittext's addTextChangedListener method, everything is  working perfectly but when I change language (locale) my addTextChangedListener is not working.</p>
  
  <pre><code>double answer = inputDouble * counterToDouble;
  DecimalFormat df = new DecimalFormat("##.########");
  // df=(DecimalFormat)numberFormat;
  
  df.setRoundingMode(RoundingMode.DOWN);
  answer = Double.parseDouble(df.format(answer));
  
  unicoinsAmmount.setText(String.valueOf(df.format(answer)));
  </code></pre>
  
  <p>I searched about my problem and found a <code>NumberFormat</code> solution:</p>
  
  <pre><code>NumberFormat numberFormat = NumberFormat.getNumberInstance(Locale.US);
  </code></pre>
  
  <p>but I don't know how I can use this code.</p>