MVC模式介绍

import java.util.Observable;
class Sphere extends Observable
{
....
public void setRadius(double r)
 {
  myRadius = r;
  setChanged();         // Indicates that the model has changed
  notifyObservers();
 }
....
}

import java.util.Observer;
import java.util.Observable;

public class TextView extends JPanel implements Observer
{
......
 public void update(Observable o, Object arg)
 {
  Sphere balloon = (Sphere)o; 
  radiusIn.setText(“ ”+f3.format(balloon.getRadius()));
  volumeOut.setText(“ ”+f3.format(balloon.volume()));
  surfAreaOut.setText(“ ” + f3.format(balloon.surfaceArea()));
 }
......
}

public SphereWindow()
{
 super(“Spheres: volume and surface area”);
 model = new Sphere(0, 0, 100);
 TextView view = new TextView();
 model.addObserver(view);
 view.update(model, null);
 view.addActionListener(this);
 Container c = getContentPane();
 c.add(view);
}

public void actionPerformed(ActionEvent e)
{
 JTextField t = (JTextField)e.getSource();    
 double r = Double.parseDouble(t.getText());
 model.setRadius(r);
}

public SphereWindow()
  {
   super(“Spheres: volume and surface area”);
   model = new Sphere(0, 0, 100);
   TextView tView = new TextView();
   model.addObserver(tView);
   tView.addActionListener(this);
   tView.update(model, null);
   GraphicsView gView = new GraphicsView();
   model.addObserver(gView);
   gView.update(model, null);

   Container c = getContentPane();
   c.setLayout(new GridLayout(1, 2));
   c.add(tView);
   c.add(gView);
  }

public SphereWindow()
  {
   super(“Spheres: volume and surface area”);
   Sphere model = new Sphere(0, 0, 100);
   TextController tController = new TextController(model);
   GraphicsController gController = new GraphicsController(model);

   Container c = getContentPane();
   c.setLayout(new GridLayout(1, 2));
   c.add(tController.getView());
   c.add(gController.getView());
  }