多级 Sankey 图表（Multilevel Sankey Chart）

以下是具有多个级别的SanKey图表的示例。

我们已经在Google Charts Configuration Syntax一章中看到了用于绘制图表的配置 。 现在，让我们看一个具有多个级别的SanKey图表的示例。

配置 (Configurations)

我们使用Sankey类来显示具有多个级别的Sankey图表。

Sankey chart = new Sankey();

例子 (Example)

HelloWorld.java

package cn.xnip.client;
import com.google.gwt.core.client.EntryPoint;
import com.google.gwt.user.client.ui.RootPanel;
import com.googlecode.gwt.charts.client.ChartLoader;
import com.googlecode.gwt.charts.client.ChartPackage;
import com.googlecode.gwt.charts.client.ColumnType;
import com.googlecode.gwt.charts.client.DataTable;
import com.googlecode.gwt.charts.client.sankey.Sankey;
public class HelloWorld implements EntryPoint {
   private Sankey chart;
   private void initialize() {
      ChartLoader chartLoader = new ChartLoader(ChartPackage.SANKEY);
      chartLoader.loadApi(new Runnable() {
         public void run() {
            // Create and attach the chart
            chart = new Sankey();
            RootPanel.get().add(chart);
            draw();
         }
      });
   }
   private void draw() {
      // Prepare the data
      DataTable data = DataTable.create();
      data.addColumn(ColumnType.STRING, "From");
      data.addColumn(ColumnType.STRING, "To");
      data.addColumn(ColumnType.NUMBER, "Weight");
      data.addRow("Brazil","Portugal",5);
      data.addRow("Brazil","France",1 );
      data.addRow("Brazil","Spain",1 );
      data.addRow("Brazil","England",1 );
      data.addRow("Canada","Portugal",1 );
      data.addRow("Canada","France",5 );
      data.addRow("Canada","England",1 );
      data.addRow("Mexico","Portugal",1 );
      data.addRow("Mexico","France",1 );
      data.addRow("Mexico","Spain",5 );
      data.addRow("Mexico","England",1 );
      data.addRow("USA","Portugal",1 );
      data.addRow("USA","France",1 );
      data.addRow("USA","Spain",1 );
      data.addRow("USA","England",5);     
      data.addRow("Portugal","Angola", 2 );
      data.addRow("Portugal","Senegal", 1 );
      data.addRow("Portugal", "Morocco", 1 );
      data.addRow("Portugal","South Africa", 3 );
      // Draw the chart
      chart.draw(data);
      chart.setWidth("400px");
      chart.setHeight("400px");
   }
   public void onModuleLoad() {
      initialize();
   }
}

结果 (Result)

验证结果。