Android aChartEngine - button and chart on the same activity

Question

I'm trying to display a button, a TextView area and a real time graph (using the aChartEngine library) on the same activity.

The user enters some information on the TextView, then click on the button to send it (through a OnClickListener()). Then this listener creates a line graph and calls a web service which will return a value. Every 5 seconds the returned value is refreshed and the graph is updated.

The problem is that I can't manage to display the graph on the MainActivity(with the button and the TextView). How can I display the three of them in the same Activity?

I tried using this but it didn't work:

LinearLayout layout = (LinearLayout) findViewById(R.id.chart);
chartView = ChartFactory.getTimeChartView(getBaseContext(), dataset, renderer, "Test"); 
layout.addView(chartView);

And here is my code so far:

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    send = (Button)this.findViewById(R.id.send);
    textArea = (EditText) this.findViewById(R.id.textarea); 
    send.setOnClickListener(sendForm);
}

@Override
protected void onStart() {
    super.onStart();
    dataset.addSeries(timeSeries);
    chartView = ChartFactory.getTimeChartView(this, dataset, renderer, "Test");
    chartView.refreshDrawableState();
    chartView.repaint();
    setContentView(chartView); 
}

OnClickListener sendForm = new OnClickListener() { 
    @Override
    public void onClick(View v) {
        webServiceParameter = textArea.getText().toString().trim();
        dataset = new XYMultipleSeriesDataset();
        renderer = new XYMultipleSeriesRenderer();
        myChartSettings(renderer);
        rendererSeries = new XYSeriesRenderer();
        myPointSettings(rendererSeries);
        renderer.addSeriesRenderer(rendererSeries); 
        timeSeries = new TimeSeries("");
        mThread = new Thread(){
            public void run(){
                while(true){
                    try {
                        Thread.sleep(5000L);
                    } catch (InterruptedException e) {
                    e.printStackTrace();
                    }

                    //call the web service and return a value
                    timeSeries.add(new Date(), returnedValue);
                    chartView.repaint();
                }
            }
        };
        mThread.start();
    }
};

EDIT: Problem solved, I started from scratch and deleted the onStart() function. Then on the onCreate() I just had to write this:

dataset = new XYMultipleSeriesDataset(); 
renderer = new XYMultipleSeriesRenderer();
rendererSeries = new XYSeriesRenderer();
myChartSettings(renderer);
myPointSettings(rendererSeries);
renderer.addSeriesRenderer(rendererSeries);
timeSeries = new TimeSeries("");
dataset.addSeries(timeSeries); 
chartView = ChartFactory.getTimeChartView(this, dataset, renderer, "Test");
chartView.refreshDrawableState();
chartView.repaint();
layout.addView(chartView);