@Override public String filter(String value,String previousValue){
  if (previousValue != null && value.length() > previousValue.length())   return value;
  return value.equals("0") || value.equals("0.0") ? "" : value;
}

@ Override public String filter ( String value , String previousValue ) { if ( previousValue != null && value . length ( ) > previousValue . length ( ) ) return value ; return value . equals ( "0" ) || value . equals ( "0.0" ) ? "" : value ; }
the default filter removes the display of ' 0 ' or ' 0 . 0 ' if the user has erased the text . this is to prevent a number being shown when the user tries to erase it .
