Java图形界面设计

一、总述

Java的图形用户界面由各种组件（component）构成，它们主要位于java.awt包与javax.swing包中。Swing与AWT最大的不同是，Swing在实现时，不包含任何本地代码(native)，是一种“轻量级(lightweight)”的组件

Swing具有状态的组件。

二、容器

1.顶层容器：

JFrame、JApplet、JDialog 和 JWindow

2.JFrame创建的一个程序

2.1代码

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

  public class JFrameDemo{
     public static void main(String args[]){
         JFrame frame = new JFrame("JFrameDemo");
         JButton button = new JButton("Press Me");

         //first way to do that
         // frame.getContentPane().add(button,BorderLayout.CENTER);


         //another way to set the Pane
         JPanel contentPane = new JPanel();
         contentPane.setLayout(new BorderLayout());
         contentPane.add(button,BorderLayout.CENTER);
         frame.setContentPane(contentPane);

         //frame.pack();
         frame.setVisible(true);
     }
  }

2.2执行结果

3.面板（JPanel）

可以相互嵌套，不能独立存在，只能添加到其他窗口内部。

3.1代码

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

  public class FrameWithPanel{
     public static void main(String args[]){
     JFrame frame = new JFrame("Frame with Panel");
     Container contentPane = frame.getContentPane();
     contentPane.setBackground(Color.CYAN);

     JPanel panel = new JPanel();
     panel.setBackground(Color.yellow);

     JButton button = new JButton("Press me");
     panel.add(button);
     //add JButton instance to JPanel

     //add JPanel instance to JFrame's south
     contentPane.add(panel,BorderLayout.SOUTH);
     frame.setSize(300,200);
     frame.setVisible(true);
     }
  }

3.2执行结果

三、布局

1.总述

组件的布局（包括位置与大小）通常由Layout Manager负责安排。Java平台提供了多种布局管理器，以下对其部分，进行说明。

2.FlowLayout Layout Manager

2.1FlowLayout 的三种构造方法

 public FlowLayout()
     public FlowLayout(int align)
     public FlowLayout(int align,int hgap,int vgap)

构造方法中，提供了一个对齐方式的可选项align，取值有三种形式：FlowLayout.LEFT、 FlowLayout.CENTER 、FlowLayout.RIGHT。hgap和vgap可以设定组件的水平间距和垂直距离。

2.2参考代码

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

  public class FlowLayoutDemo{
     private JFrame frame;
     private JButton btn1,btn2,btn3;

     public static void main(String args[]){
     FlowLayoutDemo that = new FlowLayoutDemo();
     that.go();
     }
     public void go(){
     frame = new JFrame("Flow Layout");
     Container contentPane = frame.getContentPane();

     contentPane.setLayout(new FlowLayout());

     btn1 = new JButton("OK");
     btn2 = new JButton("Open");
     btn3 = new JButton("Close");

     contentPane.add(btn1);
     contentPane.add(btn2);
     contentPane.add(btn3);

     frame.setSize(300,200);
     frame.setVisible(true);
     }
  }

2.3执行结果

改变Frame的大小，Frame中组件的布局也会随之改变。

3.BorderLayout 布局管理器

3.1概述

BorderLayout是顶层窗口中内容窗格的默认布局管理器，被划分为BorderLayout.NORTH、BorderLayout.SOUTH、BorderLayout.WEST、BorderLayout.EAST、BorderLayout.CENTER 五个区域。

3.2构造函数

 BorderLayout()
     BorderLayout(int,int)

3.3示例代码

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

  public class BorderLayoutDemo{
     private JFrame frame;
     private JButton be,bw,bn,bs,bc;

     public static void main(String args[]){
     BorderLayoutDemo that = new BorderLayoutDemo();
     that.go();
     }
     public void go(){
     frame = new JFrame("Border Layout");
     be = new JButton("East");
     bw = new JButton("West");
     bn = new JButton("North");
     bs = new JButton("South");
     bc = new JButton("Center");

     frame.getContentPane().add(be,"East");
     frame.getContentPane().add(bw,BorderLayout.WEST);
     frame.getContentPane().add(bn,BorderLayout.NORTH);
     frame.getContentPane().add(bs,BorderLayout.SOUTH);
     frame.getContentPane().add(bc,BorderLayout.CENTER);

     frame.setSize(350,200);
     frame.setVisible(true);
     }
  }

3.4执行结果

4.GridLayout布局管理器

4.1总述

是一种网格式的布局管理器，将窗口空间分割成若干行，乘若干列的网格。组件依次放入，占一格。

4.2构造函数

public GridLayout()

public GridLayout(int rows, int cols)

public GridLayout(int rows, int cols, int hgap, int vgap)

4.3参考代码

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

  public class GridLayoutDemo{
     private JFrame frame;
     private JButton b1,b2,b3,b4,b5,b6;

     public static void main(String args[]){
     GridLayoutDemo that = new GridLayoutDemo();
     that.go();
     }
     public void go(){
     frame = new JFrame("Grid Frame");

     Container contentPane = frame.getContentPane();

     contentPane.setLayout(new GridLayout(3,2));

     b1 = new JButton("grid_1");
     b2 = new JButton("grid_2");
     b3 = new JButton("grid_3");
     b4 = new JButton("grid_4");
     b5 = new JButton("grid_5");
     b6 = new JButton("grid_6");

     contentPane.add(b1);
     contentPane.add(b2);
     contentPane.add(b3);
     contentPane.add(b4);
     contentPane.add(b5);
     contentPane.add(b6);

     frame.pack();
     frame.setVisible(true);
     }
  }

4.4执行结果

5.CardLayout 布局管理器

5.1总述

是一种卡片式的布局管理器，它将容器中的组件处理成一系列卡片，每一时刻只显示出其中一张。

5.2参考代码：

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

  public class CardLayoutDemo extends MouseAdapter{
     JPanel p1,p2,p3,p4,p5;
     JLabel l1, l2, l3, l4, l5;

     //declare a Cardlayout object
     CardLayout myCard;
     JFrame frame;
     Container contentPane;

     public static void main(String args[]){
     CardLayoutDemo that = new CardLayoutDemo();
     that.go();
     System.out.println("test");
     }

     public void go(){
     frame = new JFrame("Card Test");
     contentPane = frame.getContentPane();
     myCard = new CardLayout();

     contentPane.setLayout(myCard);

     p1=new JPanel();
     p2 = new JPanel();
     p3 = new JPanel();
     p4 = new JPanel();
     p5 = new JPanel();

     //set the different bk color for each JPanel label
     l1 =  new JLabel("This is the first JPanel");
     p1.add(l1);
     p1.setBackground(Color.yellow);

     l2 =  new JLabel("This is the second JPanel");
     p2.add(l2);
     p2.setBackground(Color.green);

     l3 =  new JLabel("This is the third JPanel");
     p3.add(l3);
     p3.setBackground(Color.magenta);

     l4 =  new JLabel("This is the forth JPanel");
     p4.add(l4);
     p4.setBackground(Color.white);

     l5 =  new JLabel("This is the fifth JPanel");
     p5.add(l5);
     p5.setBackground(Color.cyan);

     //set mouseListener
     p1.addMouseListener(this);
     p2.addMouseListener(this);
     p3.addMouseListener(this);
     p4.addMouseListener(this);
     p5.addMouseListener(this);

     //set each JPanle as a Card to insert frame
     contentPane.add(p1,"First");
     contentPane.add(p2,"Sencond");
     contentPane.add(p3,"Third");
     contentPane.add(p4,"Forth");
     contentPane.add(p5,"Fifth");

     //display the first pic
     myCard.show(contentPane,"First");
     frame.setSize(300,200);
      frame.show();
     }

     public void mouseClicked(MouseEvent e){
     myCard.next(contentPane);
     }
  }

5.2执行结果

6.BoxLayout布局管理器

6.1总述

将容器中的组件，按水平排成一行，或按垂直方向排成一列。

6.2构造函数

BoxLayout(Container target, int axis)

axis = BoxLayout.X_AXIS | BoxLayout.Y_AXIS

6.3参考代码

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

  public class BoxLayoutDemo{
  <span style="white-space:pre">    </span>private JFrame frame;
  <span style="white-space:pre">    </span>private JPanel pv,ph;

  <span style="white-space:pre">    </span>public static void main(String args[]){
  <span style="white-space:pre">        </span>BoxLayoutDemo that = new BoxLayoutDemo();
  <span style="white-space:pre">        </span>that.go();
  <span style="white-space:pre">    </span>}
  <span style="white-space:pre">    </span>public void go(){
  <span style="white-space:pre">        </span>frame = new JFrame("Box Layout example");
  <span style="white-space:pre">        </span>Container contentPane = frame.getContentPane();

  <span style="white-space:pre">        </span>pv = new JPanel();
  <span style="white-space:pre">        </span>pv.setLayout(new BoxLayout(pv,BoxLayout.Y_AXIS));

  <span style="white-space:pre">        </span>pv.add(new JLabel("Monday"));
  <span style="white-space:pre">        </span>pv.add(new JLabel("Tuesday"));
  <span style="white-space:pre">        </span>pv.add(new JLabel("Wednesday"));
  <span style="white-space:pre">        </span>pv.add(new JLabel("Thursday"));
  <span style="white-space:pre">        </span>pv.add(new JLabel("Friday"));
  <span style="white-space:pre">        </span>pv.add(new JLabel("Saturday"));
  <span style="white-space:pre">        </span>pv.add(new JLabel("Sunday"));

  <span style="white-space:pre">        </span>contentPane.add(pv,BorderLayout.CENTER);

  <span style="white-space:pre">        </span>ph  = new JPanel();
  <span style="white-space:pre">        </span>ph.setLayout(new BoxLayout(ph,BoxLayout.X_AXIS));

  <span style="white-space:pre">        </span>ph.add(new JButton("Yes"));
  <span style="white-space:pre">        </span>ph.add(new JButton("No"));
  <span style="white-space:pre">        </span>ph.add(new JButton("Cancle"));

  <span style="white-space:pre">        </span>contentPane.add(ph,BorderLayout.SOUTH);

  <span style="white-space:pre">        </span>frame.pack();
  <span style="white-space:pre">        </span>frame.setVisible(true);
  <span style="white-space:pre">    </span>}
  }

6.4执行结果

6.5专门使用BoxLayout的特殊容器—Box类

6.5.1创建实例的静态方法

 public static Box createHorizontalBox()
     public static Box createVerticalBox()

6.5.2｜6.3的代码，改写如下

 //the specific Box class for BoxLayout Container
  import java.awt.*;
  import javax.swing.*;

  public class BoxDemo{
     private JFrame frame;
     private Box bv,bh;

     public static void main(String arg[]){
         BoxDemo that = new BoxDemo();
         that.go();
     }
     void go(){
         frame = new JFrame("Box Layout example");
         Container contentPane = frame.getContentPane();

         bv = Box.createVerticalBox();

         bv.add(new JLabel("Monday"));
         bv.add(new JLabel("Tuesday"));
         bv.add(new JLabel("Wednesday"));
         bv.add(new JLabel("Thursday"));
         bv.add(new JLabel("Friday"));
         bv.add(new JLabel("Saturday"));
         bv.add(new JLabel("Sunday"));

         contentPane.add(bv,BorderLayout.CENTER);

         bh = Box.createHorizontalBox();
         bh.add(new JButton("Yes"));
         bh.add(new JButton("No"));
         bh.add(new JButton("Cancel"));

         contentPane.add(bh,BorderLayout.SOUTH);

         frame.setSize(300,200);
         //frame.pack();
         frame.setVisible(true);
     }
  }

6.6Box类提供的创建不可组件方法

 public static Component createHorizontalGlue()
     public static Component createHorizontalStrut(int width)
     public static Component createVerticalGlue()
     public static Component createVerticalStrut(int height)
     public static Component createRigidArea(Dimension d)

6.6.1参考代码

 //to create invisible component
  import java.awt.*;
  import javax.swing.*;

  public class GlueAndStrut{
     private JFrame frame;
     private Box b1,b2,b3,b4;

     public static void main(String args[]){
         GlueAndStrut that = new GlueAndStrut();
         that.go();
     }
     void go(){
         frame = new JFrame("Glue And Strut");
         Container contentPane = frame.getContentPane();
         contentPane.setLayout(new GridLayout(4,1));

         b1 = Box.createHorizontalBox();
         b1.add(new JLabel("Box 1:"));
         b1.add(new JButton("Yes"));
         b1.add(new JButton("No"));
         b1.add(new JButton("Cancel"));

         b2 = Box.createHorizontalBox();
         b2.add(new JLabel("Box 2:"));
         b2.add(new JButton("Yes"));
         b2.add(new JButton("No"));
         b2.add(Box.createHorizontalGlue());
         b2.add(new JButton("Cancel"));

         b3 = Box.createHorizontalBox();
         b3.add(new JLabel("Box 3:"));
         b3.add(new JButton("Yes"));
         b3.add(new JButton("No"));
         b3.add(Box.createHorizontalStrut(20));
         b3.add(new JButton("Cancel"));

         b4 = Box.createHorizontalBox();
         b4.add(new JLabel("Box 4:"));
         b4.add(new JButton("Yes"));
         b4.add(new JButton("No"));
         b4.add(Box.createRigidArea(new Dimension(10,10)));
         b4.add(new JButton("Cancel"));

         contentPane.add(b1);
         contentPane.add(b2);
         contentPane.add(b3);
         contentPane.add(b4);

         frame.setSize(300,200);
         frame.setVisible(true);
     }
  }

6.6.2执行结果

7.不使用布局管理器

7.1一般做法

a.setLayout(null)将布局管理器设置为空

b.setBounds(int x,int y,int width,int height) 设置组件的位置与大小

7.2参考代码

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

  public class NullLayoutDemo{
     private JFrame frame;
     private JButton b1,b2,b3;

     public static void main(String args[]){
         NullLayoutDemo that = new NullLayoutDemo();
         that.go();
     }
     private void go(){
         frame = new JFrame("Null Layout Demo");
         Container contentPane = frame.getContentPane();

         //set the layout as null;
         contentPane.setLayout(null);

         //add the buttons
         b1 = new JButton("Yes");
         contentPane.add(b1);
         b2 = new JButton("No");
         contentPane.add(b2);
         b3 = new JButton("Cancel");
         contentPane.add(b3);

         //set the buttons' pos and size;
         b1.setBounds(30,15,75,20);
         b2.setBounds(150,15,75,50);
         b3.setBounds(150,100,75,20);

         frame.setSize(300,200);
         frame.setVisible(true);
     }
  }

7.3执行结果