@Override
 public void onTextChanged(CharSequence s, int start, int before, int count) {
   String bankId = "";
   for (int i = 0; i < s.length(); i++) {
     if ((i + 1) % 4 == 0) {
       bankId += " ";
     }
     bankId += s.charAt(i);
   }
   bankcardnum.setText(bankId);
   Log.v(
       "TextWatcher-onTextChanged-->",
       " text="
           + s.toString()
           + " length="
           + s.length()
           + " start="
           + start
           + " before-"
           + before
           + " count="
           + count);
 }