netbeans窗体初步

  开始学java,使用netbeans,从开始学做桌面软件开始。

 

1.做一个MDI窗体

新建一个Frame,在上面在放一个JDesktopPane.再放一个菜单。

再建几个继承自JInternalFrame的类。点选菜单时执行以下代码.

private void jTableTestActionPerformed(java.awt.event.ActionEvent evt) {                         

NewJInternalFrame d = new NewJInternalFrame();

        jDesktop1.add(d, javax.swing.JLayeredPane.DEFAULT_LAYER);

        d.setVisible(true);

}

2.使MDI中子窗体不重复

点菜单时做执行如下代码.

private void jTableTestActionPerformed(java.awt.event.ActionEvent evt) {                    

    JInternalFrame[] frames = this.jDesktop1.getAllFrames();

    boolean isExisted = false;

    for (int i = 0; i < frames.length; ++i) {

        if (frames[i] instanceof NewJInternalFrame) {

            (this.jDesktop1.getDesktopManager()).activateFrame((frames[i]));

            isExisted = true;

            break;

        }    }

    if (!isExisted) {

        NewJInternalFrame d = new NewJInternalFrame();

        jDesktop1.add(d, javax.swing.JLayeredPane.DEFAULT_LAYER);

        d.setVisible(true);

    }

}

 

3.给MDI窗体加滚动条

首先继承JDesktopPane，做一个JDesktop.代码如下。

在Frame上放一个JScrollPane,在JScrollPane上放上刚做的JDesktop

public class JDesktop extends JDesktopPane

{

 public @Override void paint(Graphics g)

    {

        super.paint(g);

        Dimension d = preferredSizeOfAllFrames();

        this.setPreferredSize(d);

        this.revalidate();

 }

 

 /**

   * @return 返回最佳desktop尺寸..

   * 注：往左移时，尺寸没有变化，需改进。

   */

    public Dimension preferredSizeOfAllFrames()

    {

        JInternalFrame [] array = getAllFrames();

 

        int maxX = 0;

        int maxY = 0;

        for (int i = 0; i < array.length; i++)

        {

            if ( array[ i ].isVisible() )

            {

                int cx;

                cx = array[i].getX();

                int x = cx + array[i].getWidth();

                if (x > maxX) maxX = x;

                int cy;

                cy = array[i].getY();

                int y = cy + array[i].getHeight();

                if (y > maxY) maxY = y;

            }

        }

        return new Dimension(maxX, maxY);

    }

 

}

 

5.使Frame屏幕居中

public MainFrame() {

        initComponents();

       //以下是netbeans生成的代码

        setLocationRelativeTo(null); //只需加这一句

 

6.设置启动窗体

只需新增一个独立类，这个类只需有以下一个方法.

public class Main {

 public static void main(String args[]) {

        java.awt.EventQueue.invokeLater(new Runnable() {

            public void run() {

                new MainFrame().setVisible(true);//这句设置第一个显示窗体

            }

        });

    }

}

7.制作PictureBox

直接用label

 

8.设计登录窗体

将登录窗体设为启动窗体(参考6)，点登录按钮时，执行如下代码.

private void btnLoginActionPerformed(java.awt.event.ActionEvent evt) {                             

    if(!this.txtUserNo.getText().equals(""))

    {

        this.dispose();//这个函数好像已过时了。

        new MainFrame().setVisible(true);

    }

    else

    {

         JOptionPane.showMessageDialog(this, "对不起!用户名不能为空.", "错误提示", JOptionPane.ERROR_MESSAGE);

    }

}       

 

9.添加事件
class TableSelectionFrame extends JFrame implements MouseListener {
        private DefaultTableModel model;

        private JTable table;

        public TableSelectionFrame() {
                setTitle("TableSelectionTest");
                setSize(300, 200);
                addWindowListener(new WindowAdapter() {
                        public void windowClosing(WindowEvent e) {
                                System.exit(0);
                        }
                });

                model = new DefaultTableModel(10, 10);

                for (int i = 0; i < model.getRowCount(); i++)
                        for (int j = 0; j < model.getColumnCount(); j++)
                                model.setValueAt(new Integer((i + 1) * (j + 1)), i, j);

                table = new JTable(model);

                table.addMouseListener(this);

                Container contentPane = getContentPane();
                contentPane.add(new JScrollPane(table), "Center");

                table.setCellSelectionEnabled(true);
        }

        public void mouseClicked(MouseEvent e) {
                int row = table.getSelectedRow();
                int column = table.getSelectedColumn();
                System.out.println(model.getValueAt(row, column));
        }

        public void mouseEntered(MouseEvent e) {
        }

        public void mouseExited(MouseEvent e) {
        }

        public void mousePressed(MouseEvent e) {
        }

        public void mouseReleased(MouseEvent e) {
        }
}      

 

10.反射生成子窗口
步骤１：
    private void showInternalFrame(String[] args) {
        JInternalFrame[] frames = this.jDesktop1.getAllFrames();
        boolean isExisted = false;
        for (int i = 0; i < frames.length; ++i) {
           if (frames[i].getClass().getName().equals(args[0])) {
                (this.jDesktop1.getDesktopManager()).activateFrame((frames[i]));
                isExisted = true;
                break;
            }
        }
        if (!isExisted) {
            try {
                Class classDefinition = Class.forName(args[0]);
                Object obj = classDefinition.newInstance();
                jDesktop1.add((JInternalFrame) obj, javax.swing.JLayeredPane.DEFAULT_LAYER);
                ((JInternalFrame) obj).setVisible(true);
            } catch (InstantiationException ex) {
                Logger.getLogger(MainFrame.class.getName()).log(Level.SEVERE, null, ex);
            } catch (IllegalAccessException ex) {
                Logger.getLogger(MainFrame.class.getName()).log(Level.SEVERE, null, ex);
            } catch (ClassNotFoundException ex) {
                Logger.getLogger(MainFrame.class.getName()).log(Level.SEVERE, null, ex);
            }
        }

    }
步骤２：调用
showInternalFrame(new String[]{"javaapplication1.DefineEditor"});