在JUNG图的边缘放置一个字符串

Question

我试图将一个字符串文本放到JUNG树图的边缘。见下面的例子。 我尝试是简单地添加这一行：

graph.addEdge("arrow", "Vmain", "Vsecond"); 

...但没有任何结果（参见下文截图）。我需要一些建议。

import java.awt.BorderLayout; 
import java.awt.Color; 
import java.awt.Container; 
import java.awt.Dimension; 
import java.awt.GridLayout; 
import java.awt.event.ActionEvent; 
import java.awt.event.ActionListener; 
import javax.swing.BorderFactory; 
import javax.swing.JApplet; 
import javax.swing.JButton; 
import javax.swing.JComboBox; 
import javax.swing.JFrame; 
import javax.swing.JPanel; 
import org.apache.commons.collections15.Factory; 
import edu.uci.ics.jung.algorithms.layout.TreeLayout; 
import edu.uci.ics.jung.graph.DirectedGraph; 
import edu.uci.ics.jung.graph.DirectedSparseMultigraph; 
import edu.uci.ics.jung.graph.Forest; 
import edu.uci.ics.jung.graph.DelegateForest; 
import edu.uci.ics.jung.graph.DelegateTree; 
import edu.uci.ics.jung.graph.Tree; 
import edu.uci.ics.jung.visualization.GraphZoomScrollPane; 
import edu.uci.ics.jung.visualization.VisualizationViewer; 
import edu.uci.ics.jung.visualization.control.CrossoverScalingControl; 
import edu.uci.ics.jung.visualization.control.DefaultModalGraphMouse; 
import edu.uci.ics.jung.visualization.control.ModalGraphMouse; 
import edu.uci.ics.jung.visualization.control.ScalingControl; 
import edu.uci.ics.jung.visualization.decorators.EdgeShape; 
import edu.uci.ics.jung.visualization.decorators.ToStringLabeller; 

public class TreeVisualiser extends JApplet { 

    Forest<String, String> graph; 

    Factory<DirectedGraph<String, String>> graphFactory = new Factory<DirectedGraph<String, String>>() { 
     public DirectedGraph<String, String> create() { 
      return new DirectedSparseMultigraph<String, String>(); 
     } 
    }; 

    Factory<Tree<String, String>> treeFactory = new Factory<Tree<String, String>>() { 
     public Tree<String, String> create() { 
      return new DelegateTree<String, String>(graphFactory); 
     } 
    }; 

    VisualizationViewer<String, String> vv; 
    String root; 
    TreeLayout<String, String> treeLayout; 

    @SuppressWarnings({"rawtypes", "unchecked"}) 
    public TreeVisualiser() { 

     // create a simple graph for the demo 
     graph = new DelegateForest<String, String>(); 

     createTree(); 

     treeLayout = new TreeLayout<String, String>(graph); 
     vv = new VisualizationViewer<String, String>(treeLayout, new Dimension(600, 600)); 
     vv.setBackground(Color.white); 
     vv.getRenderContext().setEdgeShapeTransformer(new EdgeShape.Line()); 
     vv.getRenderContext().setVertexLabelTransformer(new ToStringLabeller()); 
     // add a listener for ToolTips 
     vv.setVertexToolTipTransformer(new ToStringLabeller()); 

     Container content = getContentPane(); 
     final GraphZoomScrollPane panel = new GraphZoomScrollPane(vv); 
     content.add(panel); 

     final DefaultModalGraphMouse graphMouse = new DefaultModalGraphMouse(); 

     vv.setGraphMouse(graphMouse); 

     JComboBox modeBox = graphMouse.getModeComboBox(); 
     modeBox.addItemListener(graphMouse.getModeListener()); 
     graphMouse.setMode(ModalGraphMouse.Mode.TRANSFORMING); 

     final ScalingControl scaler = new CrossoverScalingControl(); 

     JButton plus = new JButton("+"); 
     plus.addActionListener(new ActionListener() { 
      public void actionPerformed(ActionEvent e) { 
       scaler.scale(vv, 1.1f, vv.getCenter()); 
      } 
     }); 
     JButton minus = new JButton("-"); 
     minus.addActionListener(new ActionListener() { 
      public void actionPerformed(ActionEvent e) { 
       scaler.scale(vv, 1/1.1f, vv.getCenter()); 
      } 
     }); 

     JPanel scaleGrid = new JPanel(new GridLayout(1, 0)); 
     scaleGrid.setBorder(BorderFactory.createTitledBorder("Zoom")); 

     JPanel controls = new JPanel(); 
     scaleGrid.add(plus); 
     scaleGrid.add(minus); 
     controls.add(scaleGrid); 
     controls.add(modeBox); 

     content.add(controls, BorderLayout.SOUTH); 
    } 

    private void createTree() { 

     graph.addEdge("arrow", "Vmain", "Vsecond"); 
    } 

    public static void main(String[] args) { 
     JFrame frame = new JFrame(); 
     Container content = frame.getContentPane(); 
     frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 

     content.add(new TreeVisualiser()); 
     frame.pack(); 
     frame.setVisible(true); 
    } 
} 

Answer 1

哦，我错过了这行代码。现在它正在按我的要求工作。

vv.getRenderContext().setEdgeLabelTransformer(new ToStringLabeller());