private int year = 2015;
SimpleDateFormat sdf = new SimpleDateFormat("hh:mm:ss.SSS");
private int[] mColors = {Color.BLUE,Color.YELLOW,Color.CYAN,Color.MAGENTA,Color.GREEN};
private int mCurrentColorIndex = 0;

private synchronized void addEntry(String id, float value) {

    LineData data = mChart.getData();

    if (data != null) {

        ILineDataSet set = data.getDataSetByLabel(id,true);
        //ILineDataSet set1 = data.getDataSetByIndex(0);


        if (set == null) {
            set = createSet(id, mColors[(mCurrentColorIndex++)%mColors.length ]);
            data.addDataSet(set);
        }


        String xValue = sdf.format(new Date());

        // add a new x-value first
        data.addXValue(xValue);
        set.addEntry(new Entry(value, set.getEntryCount(), 0));


        // let the chart know it's data has changed
        mChart.notifyDataSetChanged();

        // limit the number of visible entries
        mChart.setVisibleXRangeMaximum(30);
        // mChart.setVisibleYRange(30, AxisDependency.LEFT);

        // move to the latest entry
        mChart.moveViewToX(data.getXValCount() - 31);

        // this automatically refreshes the chart (calls invalidate())
        // mChart.moveViewTo(data.getXValCount()-7, 55f,
        // AxisDependency.LEFT);
    }
}

private LineDataSet createSet(String label, int color) {

    LineDataSet set = new LineDataSet(null, label);
    set.setAxisDependency(AxisDependency.LEFT);
    set.setColor(color);
    set.setCircleColor(Color.WHITE);
    set.setLineWidth(2f);
    set.setCircleRadius(4f);
    set.setFillAlpha(65);
    set.setFillColor(color);
    set.setHighLightColor(Color.rgb(244, 117, 117));
    set.setValueTextColor(Color.WHITE);
    set.setValueTextSize(9f);
    set.setDrawValues(false);
    return set;
}

private void feedMultiple() {

    new Thread(new Runnable() {

        @Override
        public void run() {
            for(int i = 0; i < 50; i++) {

                runOnUiThread(new Runnable() {

                    @Override
                    public void run() {
                        addEntry("name1", (float)(Math.random() * 40) + 30f);
                    }
                });
                try {
                    Thread.sleep(35);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }
    }).start();

    new Thread(new Runnable() {

        @Override
        public void run() {
            for(int i = 0; i < 100; i++) {

                runOnUiThread(new Runnable() {

                    @Override
                    public void run() {
                        addEntry("name2", (float)(Math.random() * 40) + 30f);
                    }
                });
                try {
                    Thread.sleep(35);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }
    }).start();

}

//set.addEntry(new Entry(value, set.getEntryCount(), 0)); //incorrect
set.addEntry(new Entry(value, data.getXValCount(), 0)); //correct