Java基础之创建窗口——使用边界布局管理器（TryBorderLayout)

控制台程序。

边界布局管理器最多能在容器中放置5个组件。在这种布局管理器中，可以把组件放在容器的任意一个边界上，也可以把组件放在容器的中心。每个位置只能放置一个组件。如果把组件放置在已被占用的边界上，前一个组件就会被取代。要选择边界，应指定约束，约束可以是NORTH、SOUTH、EAST、WEST或CENTER。它们都是BorderLayout类中定义的final static常量。

 import javax.swing.*;
 import javax.swing.SwingUtilities;
 import java.awt.*;
 import javax.swing.border.EtchedBorder;

 public class TryBorderLayout {

   public static void createWindow(){
     JFrame aWindow = new JFrame("This is the Window Title");
     Toolkit theKit = aWindow.getToolkit();                             // Get the window toolkit
     Dimension wndSize = theKit.getScreenSize();                        // Get screen size

     // Set the position to screen center & size to half screen size
     aWindow.setSize(wndSize.width/2, wndSize.height/2);                // Set window size
     aWindow.setLocationRelativeTo(null);                               // Center window
     aWindow.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

     BorderLayout border = new BorderLayout();                          // Create a layout manager
     Container content = aWindow.getContentPane();                      // Get the content pane
     content.setLayout(border);                                         // Set the container layout mgr
     EtchedBorder edge = new EtchedBorder(EtchedBorder.RAISED);         // Button border

     // Now add five JButton components and set their borders
     JButton button;
     content.add(button = new JButton("EAST"), BorderLayout.EAST);
     button.setBorder(edge);
     content.add(button = new JButton("WEST"), BorderLayout.WEST);
     button.setBorder(edge);
     content.add(button = new JButton("NORTH"), BorderLayout.NORTH);
     button.setBorder(edge);
     content.add(button = new JButton("SOUTH"), BorderLayout.SOUTH);
     button.setBorder(edge);
     content.add(button = new JButton("CENTER"), BorderLayout.CENTER);
     button.setBorder(edge);

     aWindow.setVisible(true);                                          // Display the window
   }

   public static void main(String[] args) {
     SwingUtilities.invokeLater(new Runnable() {
             public void run() {
                 createWindow();
             }
         });
   }
 }