A method always returning null

  android, java, methods
decibelChart.postDelayed(new Runnable() {
                        @Override
                        public void run() {
                            int chartValue;
                            decibelChart.setNoDataText("Drawing Decibel Chart Error !");
                            decibelChart.setDragEnabled(false);
                            decibelChart.setScaleEnabled(false);
                            decibelChart.setDrawGridBackground(false);
                            decibelChart.setPinchZoom(false);
                            decibelChart.setBackgroundColor(Color.TRANSPARENT);
                            decibelChart.setData(lineData);

                            if (mediaRecorderForDB != null) {
                                chartValue = mediaRecorderForDB.getMaxAmplitude();
                            } else if (mediaRecorder != null) {
                                chartValue = mediaRecorder.getMaxAmplitude();
                            } else
                                chartValue = 0;

                            LineData myData = decibelChart.getData();

                            if (myData != null) {
                                ILineDataSet set = myData.getDataSetByIndex(0);

                                if (set == null){
                                    LineDataSet dataSet = new LineDataSet(null,"Dynamic");
                                    dataSet.setAxisDependency(YAxis.AxisDependency.LEFT);
                                    dataSet.setLineWidth(3f);
                                    dataSet.setColor(Color.WHITE);
                                    dataSet.setMode(LineDataSet.Mode.CUBIC_BEZIER);
                                    dataSet.setCubicIntensity(1f);
                                    myData.addDataSet(dataSet);
                                }

                                myData.addEntry(new Entry(set.getEntryCount(), chartValue + 5), 0);
                                myData.notifyDataChanged();
                                decibelChart.setMaxVisibleValueCount(150);
                                decibelChart.moveViewToX(myData.getEntryCount());
                            }

                            Log.e("[CHART_ERROR]", "CHART DRAWING");

                        }
                    },250);

set.getEntryCount() returns null and throws exception. How can i get over it ? I tried a lot things but cannot achived.
The values are coming from the microphone they are decibel values. I want to draw a line chart for these values.

Source: Android Questions

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