drawfigureframe.java

Java实例入门

package drawfigure;

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class DrawFigureFrame extends JFrame {
  JPanel contentPane;
  JMenuBar jMenuBar1 = new JMenuBar();
  JMenu jMenuFile = new JMenu();
  JMenuItem jMenuFileExit = new JMenuItem();
  JMenu jMenuHelp = new JMenu();
  JMenuItem jMenuHelpAbout = new JMenuItem();
  BorderLayout borderLayout1 = new BorderLayout();
  JMenuItem jMenuItemClear = new JMenuItem();
  JMenu jMenu1 = new JMenu();
  JMenuItem jMenuItemLine = new JMenuItem();
  JMenuItem jMenuItemRet = new JMenuItem();
  JMenuItem jMenuItemOval = new JMenuItem();
  DrawFigurePanel panel = new DrawFigurePanel();

  /**Construct the frame*/
  public DrawFigureFrame() {
    enableEvents(AWTEvent.WINDOW_EVENT_MASK);
    try {
      jbInit();
    }
    catch(Exception e) {
      e.printStackTrace();
    }
  }
  /**Component initialization*/
  private void jbInit() throws Exception  {
    //setIconImage(Toolkit.getDefaultToolkit().createImage(DrawFigureFrame.class.getResource("[Your Icon]")));
    contentPane = (JPanel) this.getContentPane();
    contentPane.setLayout(borderLayout1);
    jMenuItemRet.addActionListener(new java.awt.event.ActionListener() {
      public void actionPerformed(ActionEvent e) {
        jMenuItemRet_actionPerformed(e);
      }
    });
    jMenuItemOval.addActionListener(new java.awt.event.ActionListener() {
      public void actionPerformed(ActionEvent e) {
        jMenuItemOval_actionPerformed(e);
      }
    });
    jMenuItemClear.addActionListener(new java.awt.event.ActionListener() {
      public void actionPerformed(ActionEvent e) {
        jMenuItemClear_actionPerformed(e);
      }
    });
    contentPane.add(panel);
    this.setSize(new Dimension(400, 300));
    this.setTitle("画图");
    jMenuFile.setText("File");
    jMenuFileExit.setText("Exit");
    jMenuFileExit.addActionListener(new ActionListener()  {
      public void actionPerformed(ActionEvent e) {
        jMenuFileExit_actionPerformed(e);
      }
    });
    jMenuHelp.setText("Help");
    jMenuHelpAbout.setText("About");
    jMenuHelpAbout.addActionListener(new ActionListener()  {
      public void actionPerformed(ActionEvent e) {
        jMenuHelpAbout_actionPerformed(e);
      }
    });
    jMenuItemClear.setText("Clear");
    jMenu1.setText("Draw");
    jMenuItemLine.setText("Line");
    jMenuItemLine.addActionListener(new java.awt.event.ActionListener() {
      public void actionPerformed(ActionEvent e) {
        jMenuItemLine_actionPerformed(e);
      }
    });
    jMenuItemRet.setText("Rectangle");
    jMenuItemOval.setText("Oval");
    jMenuFile.add(jMenuItemClear);
    jMenuFile.add(jMenuFileExit);
    jMenuHelp.add(jMenuHelpAbout);
    jMenuBar1.add(jMenuFile);
    jMenuBar1.add(jMenu1);
    jMenuBar1.add(jMenuHelp);
    jMenu1.add(jMenuItemLine);
    jMenu1.add(jMenuItemRet);
    jMenu1.add(jMenuItemOval);
    this.setJMenuBar(jMenuBar1);
  }
  /**File | Exit action performed*/
  public void jMenuFileExit_actionPerformed(ActionEvent e) {
    System.exit(0);
  }
  /**Help | About action performed*/
  public void jMenuHelpAbout_actionPerformed(ActionEvent e) {
    DrawFigureFrame_AboutBox dlg = new DrawFigureFrame_AboutBox(this);
    Dimension dlgSize = dlg.getPreferredSize();
    Dimension frmSize = getSize();
    Point loc = getLocation();
    dlg.setLocation((frmSize.width - dlgSize.width) / 2 + loc.x, (frmSize.height - dlgSize.height) / 2 + loc.y);
    dlg.setModal(true);
    dlg.show();
  }
  /**Overridden so we can exit when window is closed*/
  protected void processWindowEvent(WindowEvent e) {
    super.processWindowEvent(e);
    if (e.getID() == WindowEvent.WINDOW_CLOSING) {
      jMenuFileExit_actionPerformed(null);
    }
  }

  void jMenuItemLine_actionPerformed(ActionEvent e) {
    panel.figure = new LineFigure();
  }

  void jMenuItemRet_actionPerformed(ActionEvent e) {
    panel.figure = new RectangleFigure();
  }

  void jMenuItemOval_actionPerformed(ActionEvent e) {
    panel.figure = new OvalFigure();
  }

  void jMenuItemClear_actionPerformed(ActionEvent e) {
     panel.figures.removeAllElements();
     panel.figure = null;
     panel.repaint();
  }
}