Update graphview daily automatically

Question

I want to create a graph that will update daily graphe (each day append new data).

I tried something like this:

Calendar calendar = Calendar.getInstance();
    int day = calendar.get(Calendar.DAY_OF_WEEK);
    @Override
    protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_home_dashboard);

      double x,y;
      x = 0;
      GraphView graph = (GraphView) findViewById(R.id.temp_graph);
      series1 = new LineGraphSeries<>();

      switch (day) {
          case Calendar.MONDAY:
              // Current day is Monday
               x = 0;
               y = 19;
               series1.appendData(new DataPoint(x, y), true, 100);
               graph.addSeries(series1);
              break;
         case Calendar.TUESDAY:
              x = 0;
              y = 19;
              series1.appendData(new DataPoint(x, y), true, 100);
              graph.addSeries(series1);
              x = 1;
              y = 22;
              series1.appendData(new DataPoint(x, y), true, 100);
              graph.addSeries(series1);
              // Current day is TUESDAY
              break;
          case Calendar.WEDNESDAY:
              // Current day is Wednesday
              break;
          case Calendar.THURSDAY:
              // Current day is THURSDAY
              break;
          case Calendar.FRIDAY:
              // Current day is FRIDAY
              break;
          case Calendar.SATURDAY:
              // Current day is Saturday
              break;
          case Calendar.SUNDAY:
              // Current day is Sunday
              break;
      }

but didn't work graph2, any suggestions ?