Question

我正在尝试显示从数据库中获取的数据并创建饼图。没有错误，但我只看到一个数据而不是所有存储的数据。我希望有人告诉我我哪里错了。

private void pie(){

        SQLiteDatabase db = new MydbHelper(getActivity()).getReadableDatabase();

    String sql = "SELECT field1, SUM(field2), color FROM Table";
    Cursor c = db.rawQuery(sql, null);
    int count = c.getCount();

    double[] values = new double[count];
    String[] categoryNames = new String[count];
    int[] colori = new int [count];

    for(int i=0; i<count; i++) {
        c.moveToNext();     
        categoryNames[i] = c.getString(0);
        values[i] = c.getDouble(1);
        colori[i] = c.getInt(2);
    }
    // Instantiating CategorySeries to plot Pie Chart       
    CategorySeries distributionSeries = new CategorySeries(" Android version distribution as on October 1, 2012");
    for(int i=0 ;i < categoryNames.length;i++){
        // Adding a slice with its values and name to the Pie Chart
        distributionSeries.add(categoryNames[i], values[i]);
    }   
    // Instantiating a renderer for the Pie Chart
    DefaultRenderer defaultRenderer  = new DefaultRenderer();       
    for(int i = 0 ;i<categoryNames.length;i++){         
        SimpleSeriesRenderer seriesRenderer = new SimpleSeriesRenderer();       

        defaultRenderer.addSeriesRenderer(seriesRenderer);
    }
    defaultRenderer.setChartTitle("Android version distribution as on October 1, 2012 ");
    defaultRenderer.setChartTitleTextSize(20);
    defaultRenderer.setZoomButtonsVisible(true);        

    Intent intent = ChartFactory.getPieChartIntent(getActivity(), distributionSeries , defaultRenderer, "AChartEnginePieChartDemo");        

    // Start Activity
    startActivity(intent);

            c.close();
            db.close();
            }

Answer 1

由于您的查询

SELECT field1, SUM(field2), color FROM Table

具有聚合函数SUM(field2)，它将所有匹配的行压缩为一行。对于非聚合投影field1，将采用最后一行的值。

Android - 为什么我在创建图表时只看到一个数据

1 个答案: