主题：课件16下载——swing窗体

2、基于swing包的新型窗体程序
2、1 窗体的建立
先看一个最为简单的窗体例子，如：
import javax.swing.*;
import java.awt.*;

public class exec
{
        public static void main(String args[])
        {
                JFrame f=new JFrame("This is a window!");
                f.setLocation(100,200);
                f.setSize(200,400);
                
                FlowLayout fl=new FlowLayout();
                f.getContentPane().setLayout(fl);
                
                JButton[] jb=new JButton[10];
                
                for(int i=0;i<jb.length;i++)
                {
                        jb=new JButton();
                        jb.setText(String.valueOf(i));
                        f.getContentPane().add(jb);
                }
                
                f.setVisible(true);
        }
}

请注意和上述awt窗体的异同点：
1）导入的包不一样。
2）swing组件类名称和awt组件类名称相比，往往都是多个大写的“J”开头。
3）不再直接向窗体添加组件，而是通过内容面板间接添加组件，所以，在添加组件的时候，需要取得当前窗体的内容面板。
4）传统awt组件的一些方法不再鼓励使用，相反，可以使用具有相似功能的新的方法，如按钮的setLabel()方法被setText()取代，当然，传统方法仍然可以使用。这些可以在编译Java程序时，通过指定-deprecation参数来查看相关信息，如对于使用按钮setLabel()方法的swing程序，编译时键入javac -deprecation exec.java，显示警告信息为：
exec.java:22: warning: setLabel(java.lang.String) in javax.swing.AbstractButton
has been deprecated
                        jb.setLabel(String.valueOf(i));
                          ^
1 warning

2、2 常用swing组件的使用
Swing组件是AWT组件的扩展，它提供了更强大和更灵活的组件集合。除了那些常用组件如按钮、复选框和标签外，Swing还包括许多新的组件，如选项板、滚动窗口、树、表格。同时，即使是常用组件，如按钮等，在Swing都增加了新功能。另外，与AWT组件不同，Swing组件实现不包括任何与平台相关的代码。Swing组件是纯Java代码，因此与平台无关。一般用轻量级（lightweight）这个术语描述这类组件。
Swing组件还能够提供可插入的外观感觉，这意味着可以方便替换一个元素的外观和行为。这种替换可以动态实现。用户甚至可以设计自己的外观和感觉。在不久的将来，利用Swing机制实现GUI组件将完全取代AWT类。

2、2、1 swing标签的使用
import javax.swing.*;
import java.awt.*;

public class exec
{
        public static void main(String [] args)
        {
                JFrame f=new JFrame("Hello!");
                f.setLocation(10,100);
                f.setSize(600,400);
                
                f.getContentPane().setLayout(new FlowLayout());
                
                JLabel jl = new JLabel("France");
                f.getContentPane().add(jl);                                    
                
                f.setVisible(true);
        }
}
注意：可以给标签添加图片，如：
import javax.swing.*;
import java.awt.*;

public class exec
{
        public static void main(String [] args)
        {
                JFrame f=new JFrame("Hello!");
                f.setLocation(10,100);
                f.setSize(600,400);
                
                f.getContentPane().setLayout(new FlowLayout());
                ImageIcon ii = new ImageIcon("e.gif");
                JLabel jl = new JLabel("France", ii, JLabel.CENTER);
                f.getContentPane().add(jl);                                    
                
                f.setVisible(true);
        }
}

2、2、2 swing文本框的使用
import javax.swing.*;
import java.awt.*;

public class exec
{
        public static void main(String [] args)
        {
                JFrame f=new JFrame("Hello!");
                f.setLocation(10,100);
                f.setSize(600,400);
                
                f.getContentPane().setLayout(new FlowLayout());
                JTextField tf = new JTextField("France");
                tf.setColumns(10);//设置显示的列数
                f.getContentPane().add(tf);
                
                f.setVisible(true);
                f.pack();//使得窗体自动调整大小，以正好显示一个文本框
        }
}
注意：
JPasswordField类派生于JTextField，可以提供密码的输入方式，如：
import javax.swing.*;
import java.awt.*;

public class exec
{
        public static void main(String [] args)
        {
                JFrame f=new JFrame("Hello!");
                f.setLocation(10,100);
                f.setSize(600,400);
                
                f.getContentPane().setLayout(new FlowLayout());
                JPasswordField pf = new JPasswordField("France");
                pf.setColumns(10);//设置显示的列数
                f.getContentPane().add(pf);
                
                f.setVisible(true);
                f.pack();//使得窗体自动调整大小，以正好显示一个文本框
        }
}

2、2、3 swing按钮的使用
import javax.swing.*;
import java.awt.*;

public class exec
{
        public static void main(String [] args)
        {
                JFrame f=new JFrame("Hello!");
                f.setLocation(10,100);
                f.setSize(600,400);
                
                f.getContentPane().setLayout(new FlowLayout());

                JButton jb = new JButton("Ok");
                f.getContentPane().add(jb);

                f.setVisible(true);
        }
}
注意：可以给按钮添加图片，如：
import javax.swing.*;
import java.awt.*;

public class exec
{
        public static void main(String [] args)
        {
                JFrame f=new JFrame("Hello!");
                f.setLocation(10,100);
                f.setSize(600,400);
                
                f.getContentPane().setLayout(new FlowLayout());

                ImageIcon ii = new ImageIcon("e.gif");
                JButton jb = new JButton(ii);
                f.getContentPane().add(jb);

                f.setVisible(true);
        }
}

2、2、4 swing复选钮的使用
import javax.swing.*;
import java.awt.*;

public class exec
{
        public static void main(String [] args)
        {
                JFrame f=new JFrame("Hello!");
                f.setLocation(10,100);
                f.setSize(600,400);
                
                f.getContentPane().setLayout(new FlowLayout());

                JCheckBox cb1 = new JCheckBox("Java");
                JCheckBox cb2 = new JCheckBox("C++");
                
                f.getContentPane().add(cb1);
                f.getContentPane().add(cb2);

                f.setVisible(true);
        }      
}
注意：可以给复选钮添加图片，如：
import javax.swing.*;
import java.awt.*;

public class exec
{
        public static void main(String [] args)
        {
                JFrame f=new JFrame("Hello!");
                f.setLocation(10,100);
                f.setSize(600,400);
                
                f.getContentPane().setLayout(new FlowLayout());

                ImageIcon ii1 = new ImageIcon("p1.gif");
                ImageIcon ii2 = new ImageIcon("p2.gif");
                ImageIcon ii3 = new ImageIcon("p3.gif");
                
                JCheckBox cb1 = new JCheckBox("Java",ii1);
                JCheckBox cb2 = new JCheckBox("C++",ii1);
                cb1.setSelectedIcon(ii2);
                cb1.setRolloverIcon(ii3);
                
                cb2.setSelectedIcon(ii2);
                cb2.setRolloverIcon(ii3);
                
                f.getContentPane().add(cb1);
                f.getContentPane().add(cb2);

                f.setVisible(true);
        }      
}
注意：
复选钮在构造函数中的图片对象是指默认显示的图片，而setSelectedIcon()方法的功能为设置选中复选框时显示的图片，setRolloverIcon()方法的功能为设置鼠标经过复选框上方时显示的图片。

2、2、5 swing单选钮的使用
import javax.swing.*;
import java.awt.*;

public class exec
{
        public static void main(String [] args)
        {
                JFrame f=new JFrame("Hello!");
                f.setLocation(10,100);
                f.setSize(600,400);
                
                f.getContentPane().setLayout(new FlowLayout());

                JRadioButton rb1 = new JRadioButton("Java");
                JRadioButton rb2 = new JRadioButton("C++");
                ButtonGroup bg = new ButtonGroup();
                bg.add(rb1);
                bg.add(rb2);
                
                f.getContentPane().add(rb1);
                f.getContentPane().add(rb2);

                f.setVisible(true);
        }      
}
注意：
1）单选钮和复选钮的区别主要在于它一次只能选择一个，所以需要指定单选钮组来管理成为一个选项组的所有单选钮。
2）可以给单选钮添加图片，如：
import javax.swing.*;
import java.awt.*;

public class exec
{
        public static void main(String [] args)
        {
                JFrame f=new JFrame("Hello!");
                f.setLocation(10,100);
                f.setSize(600,400);
                
                f.getContentPane().setLayout(new FlowLayout());

                ImageIcon ii1 = new ImageIcon("p1.gif");
                ImageIcon ii2 = new ImageIcon("p2.gif");
                ImageIcon ii3 = new ImageIcon("p3.gif");                
                
                JRadioButton rb1 = new JRadioButton("Java",ii1);
                JRadioButton rb2 = new JRadioButton("C++",ii1);
                rb1.setRolloverIcon(ii3);
                rb1.setSelectedIcon(ii2);
                
                rb2.setRolloverIcon(ii3);
                rb2.setSelectedIcon(ii2);
                
                ButtonGroup bg = new ButtonGroup();
                bg.add(rb1);
                bg.add(rb2);
                
                f.getContentPane().add(rb1);
                f.getContentPane().add(rb2);

                f.setVisible(true);
        }      
}

2、2、6 swing组合框的使用
import javax.swing.*;
import java.awt.*;

public class exec
{
        public static void main(String [] args)
        {
                JFrame f=new JFrame("Hello!");
                f.setLocation(10,100);
                f.setSize(600,400);
                
                f.getContentPane().setLayout(new FlowLayout());

                JComboBox jc = new JComboBox();
                jc.addItem("France");
                jc.addItem("Germany");
                jc.addItem("Italy");
                jc.addItem("Japan");
                
                f.getContentPane().add(jc);

                f.setVisible(true);
        }      
}

2、2、7 swing页面框的使用
import javax.swing.*;
import java.awt.*;

public class exec
{
        public static void main(String [] args)
        {
                JFrame f=new JFrame("Hello!");
                f.setLocation(10,100);
                f.setSize(600,400);
                
                f.getContentPane().setLayout(new BorderLayout());

                JTabbedPane jtp = new JTabbedPane();
        
                Panel p1= new Panel();
                p1.setBackground(Color.red);
                p1.add(new JButton("red"));    
                jtp.addTab("red",p1);
                                
                Panel p2= new Panel();
                p2.setBackground(Color.green);
                p2.add(new JButton("green"));  
                jtp.addTab("green", p2);
                
                Panel p3= new Panel();
                p3.setBackground(Color.blue);
                p3.add(new JButton("blue"));    
                jtp.addTab("blue", p3);
                
                f.getContentPane().add(jtp,BorderLayout.CENTER);

                f.setVisible(true);
        }      
}
注意：在页面框中，每个页面都可以通过面板对象将更多的组件加入当前页面。

2、2、8 swing滚动条的使用
import javax.swing.*;
import java.awt.*;

public class exec
{
        public static void main(String [] args)
        {
                JFrame f=new JFrame("Hello!");
                f.setLocation(10,100);
                f.setSize(600,400);
                
                f.getContentPane().setLayout(new BorderLayout());
                
                JPanel jp = new JPanel();
                jp.setLayout(new GridLayout(20, 20));
                for(int i = 0; i < 400; i++)
                {
                        jp.add(new JButton("Button " + i));
                }
                
                int v = ScrollPaneConstants.VERTICAL_SCROLLBAR_AS_NEEDED;
                int h = ScrollPaneConstants.HORIZONTAL_SCROLLBAR_AS_NEEDED;
                JScrollPane jsp = new JScrollPane(jp, v, h);

                f.getContentPane().add(jsp, BorderLayout.CENTER);
                f.setVisible(true);
        }      
}
注意：滚动条作为一个不能独立使用的组件，一般要和其他组件结合才能有效的发挥功能，如给文本框、表格或者窗体添加滚动条，其中给窗体添加滚动条的做法是让窗体包含一个具有滚动条的面板。

2、2、9 swing表格的使用
import javax.swing.*;
import java.awt.*;

public class exec
{
        public static void main(String [] args)
        {
                JFrame f=new JFrame("Hello!");
                f.setLocation(10,100);
                f.setSize(600,400);
                
                f.getContentPane().setLayout(new BorderLayout());
                
                String[] colHeads = { "Name", "Phone", "Fax" };
                
                String[][] data =
                {
                        { "Gail", "4567", "8675" },
                        { "Ken", "7566", "5555" },
                        { "Viviane", "5634", "5887" },
                        { "Melanie", "7345", "9222" },
                        { "Anne", "1237", "3333" },
                        { "John", "5656", "3144" },
                        { "Matt", "5672", "2176" },
                        { "Claire", "6741", "4244" },
                        { "Erwin", "9023", "5159" },
                        { "Ellen", "1134", "5332" },
                        { "Jennifer", "5689", "1212" },
                        { "Ed", "9030", "1313" },
                        { "Helen", "6751", "1415" }
                };
                
                JTable table = new JTable(data, colHeads);
                
                int v = ScrollPaneConstants.VERTICAL_SCROLLBAR_AS_NEEDED;
                int h = ScrollPaneConstants.HORIZONTAL_SCROLLBAR_AS_NEEDED;
                JScrollPane jsp = new JScrollPane(table, v, h);
                
                f.getContentPane().add(jsp, BorderLayout.CENTER);
                
                f.setVisible(true);
        }      
}
注意：
滚动条的添加更有助于优化界面

2、2、10 swing树状视图的使用
import javax.swing.*;
import java.awt.*;
import javax.swing.tree.*;

public class exec
{
        public static void main(String [] args)
        {
                JFrame f=new JFrame("Hello!");
                f.setLocation(10,100);
                f.setSize(600,400);
                
                f.getContentPane().setLayout(new BorderLayout());
                
                DefaultMutableTreeNode top = new DefaultMutableTreeNode("Options");
                
                DefaultMutableTreeNode a = new DefaultMutableTreeNode("A");
                top.add(a);
                DefaultMutableTreeNode a1 = new DefaultMutableTreeNode("A1");
                a.add(a1);
                DefaultMutableTreeNode a2 = new DefaultMutableTreeNode("A2");
                a.add(a2);
                
                DefaultMutableTreeNode b = new DefaultMutableTreeNode("B");
                top.add(b);
                DefaultMutableTreeNode b1 = new DefaultMutableTreeNode("B1");
                b.add(b1);
                DefaultMutableTreeNode b2 = new DefaultMutableTreeNode("B2");
                b.add(b2);
                DefaultMutableTreeNode b3 = new DefaultMutableTreeNode("B3");
                b.add(b3);
                
                JTree tree = new JTree(top);
                
                f.getContentPane().add(tree, BorderLayout.CENTER);
                
                f.setVisible(true);
        }      
}