public void fitScreen(){
  Matrix save=mViewPortHandler.fitScreen();
  mViewPortHandler.refresh(save,this,false);
  calculateOffsets();
  postInvalidate();
}

public void fitScreen ( ) { Matrix save = mViewPortHandler . fitScreen ( ) ; mViewPortHandler . refresh ( save , this , false ) ; calculateOffsets ( ) ; postInvalidate ( ) ; }
resets all zooming and dragging and makes the chart fit exactly it ' s bounds .
