Android的achartengine简单的饼图

我下面的一个在这个环节例子， 创建一个类，如下

I'm following an example in this link and created a class as below

public class aChartExample {

    public Intent execute(Context context) {
        int[] colors = new int[] { Color.RED, Color.YELLOW, Color.BLUE };
        DefaultRenderer renderer = buildCategoryRenderer(colors);

        CategorySeries categorySeries = new CategorySeries("Vehicles Chart");
        categorySeries.add("cars ", 30);
        categorySeries.add("trucks", 20);
        categorySeries.add("bikes ", 60);

        return ChartFactory.getPieChartIntent(context, categorySeries, renderer, null);
    }

    protected DefaultRenderer buildCategoryRenderer(int[] colors) {
        DefaultRenderer renderer = new DefaultRenderer();
        for (int color : colors) {
            SimpleSeriesRenderer r = new SimpleSeriesRenderer();
            r.setColor(color);
            renderer.addSeriesRenderer(r);
        }
        return renderer;
    }
}

和我打电话给它，当我的应用程序就开始在OnCreate我开始活动。

and I'm calling it when my app starts on my starting activity in the onCreate.

@Override
protected void onCreate(Bundle savedInstanceState)
{
    super.onCreate(savedInstanceState);
    setContentView(R.layout.mainpage);

    Intent achartIntent = new aChartExample().execute(this);
    startActivity(achartIntent);
}

然后我包括achartengine-0.6.0.jar在我的项目。

I then included the achartengine-0.6.0.jar in my project.

当我运行它崩溃的startActivity线的应用程序。

When I run the app it crashes on the startActivity line.

不知道从哪里何去何从。

Not sure where to go from here.