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.*;
- publicclass JFrameDemo{
- publicstaticvoid 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);
- }
- }
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.*;
- publicclass FrameWithPanel{
- publicstaticvoid 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);
- }
- }
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)
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.*;
- publicclass FlowLayoutDemo{
- private JFrame frame;
- private JButton btn1,btn2,btn3;
- publicstaticvoid main(String args[]){
- FlowLayoutDemo that = new FlowLayoutDemo();
- that.go();
- }
- publicvoid 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);
- }
- }
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)
BorderLayout() BorderLayout(int,int)
3.3示例代码
- import java.awt.*;
- import javax.swing.*;
- publicclass BorderLayoutDemo{
- private JFrame frame;
- private JButton be,bw,bn,bs,bc;
- publicstaticvoid main(String args[]){
- BorderLayoutDemo that = new BorderLayoutDemo();
- that.go();
- }
- publicvoid 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);
- }
- }
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.*;
- publicclass GridLayoutDemo{
- private JFrame frame;
- private JButton b1,b2,b3,b4,b5,b6;
- publicstaticvoid main(String args[]){
- GridLayoutDemo that = new GridLayoutDemo();
- that.go();
- }
- publicvoid 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);
- }
- }
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.*;
- publicclass 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;
- publicstaticvoid main(String args[]){
- CardLayoutDemo that = new CardLayoutDemo();
- that.go();
- System.out.println("test");
- }
- publicvoid 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();
- }
- publicvoid mouseClicked(MouseEvent e){
- myCard.next(contentPane);
- }
- }
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{
private JFrame frame;
private JPanel pv,ph;
public static void main(String args[]){
BoxLayoutDemo that = new BoxLayoutDemo();
that.go();
}
public void go(){
frame = new JFrame("Box Layout example");
Container contentPane = frame.getContentPane();
pv = new JPanel();
pv.setLayout(new BoxLayout(pv,BoxLayout.Y_AXIS));
pv.add(new JLabel("Monday"));
pv.add(new JLabel("Tuesday"));
pv.add(new JLabel("Wednesday"));
pv.add(new JLabel("Thursday"));
pv.add(new JLabel("Friday"));
pv.add(new JLabel("Saturday"));
pv.add(new JLabel("Sunday"));
contentPane.add(pv,BorderLayout.CENTER);
ph = new JPanel();
ph.setLayout(new BoxLayout(ph,BoxLayout.X_AXIS));
ph.add(new JButton("Yes"));
ph.add(new JButton("No"));
ph.add(new JButton("Cancle"));
contentPane.add(ph,BorderLayout.SOUTH);
frame.pack();
frame.setVisible(true);
}
}
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
- publicstatic Box createHorizontalBox()
- publicstatic Box createVerticalBox()
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.*;
- publicclass BoxDemo{
- private JFrame frame;
- private Box bv,bh;
- publicstaticvoid 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);
- }
- }
//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
- publicstatic Component createHorizontalGlue()
- publicstatic Component createHorizontalStrut(int width)
- publicstatic Component createVerticalGlue()
- publicstatic Component createVerticalStrut(int height)
- publicstatic Component createRigidArea(Dimension d)
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.*;
- publicclass GlueAndStrut{
- private JFrame frame;
- private Box b1,b2,b3,b4;
- publicstaticvoid 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);
- }
- }
//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.*;
- publicclass NullLayoutDemo{
- private JFrame frame;
- private JButton b1,b2,b3;
- publicstaticvoid main(String args[]){
- NullLayoutDemo that = new NullLayoutDemo();
- that.go();
- }
- privatevoid 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);
- }
- }
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