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{

  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

		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