circleview.java

java程序设计 机械工业出版社 书籍代码

import java.awt.*;
import java.awt.event.*;

public class CircleView extends javax.swing.JPanel
    implements ActionListener {
  private CircleModel model;

  public void actionPerformed(ActionEvent actionEvent) {
    repaint();
  }

  /** Set a model */
  public void setModel(CircleModel newModel) {
    model = newModel;

    if (model != null)
      // Register the view as listener for the model
      model.addActionListener(this);

    repaint();
  }

  public CircleModel getModel() {
    return model;
  }

  public void paintComponent(Graphics g) {
    super.paintComponent(g);

    if (model == null) return;

    g.setColor(model.getColor());

    int xCenter = getWidth() / 2;
    int yCenter = getHeight() / 2;
    int radius = (int)model.getRadius();

    if (model.isFilled()) {
      g.fillOval(xCenter - radius, yCenter - radius,
        2 * radius, 2 * radius);
    }
    else {
      g.drawOval(xCenter - radius, yCenter - radius,
        2 * radius, 2 * radius);
    }
  }
}