public void addXValue(String xVal){
  mXValAverageLength=(mXValAverageLength + xVal.length()) / 2f;
  mXVals.add(xVal);
}

public void addXValue ( String xVal ) { mXValAverageLength = ( mXValAverageLength + xVal . length ( ) ) / 2f ; mXVals . add ( xVal ) ; }
adds a new x - value to the chart data .
