java.lang.Object
--java.awt.Component
--java.awt.Container
--java.awt.Window
--java.awt.JDialog
--javax.swing.JDialog
如果你为公司设计一套“物品工具借用系统”，在这个系统中，借用物品的员工必须详细填员工编号、借用物品、借用器具、借 用日期、预计归还日期时间、借用原因等等，若没有详细填这此数据，就无法取得准许借用物品的证明文件。因此在设计这套系统 的过程中，你必须查看用户是否已经填妥相关数据，若员工忘记了填写某些重要字段，系统应该给予警示，提醒用户哪些字段必须 填写。这个情况也常发生在网络问卷或网络会员注册系统，用户必须填写相关数据，例如用户若没有填写E-Mail邮件地址，则系统 会提示你应当填写邮件地址，否则系统将不处理用户填写的信息。
为应付这种情况，java提供了JDialog与JOptionPane供我们使用，事实上，JOptionPane是阳春版的JDialog，当你在使用 JOptionPane时，系统会自动产生JDialog组件，并将JOptionPane的内容放入JDialog的ContentPane中，而这些均由系统在背后自动 运行，并不需要由我们介入。使用JOptionPane的好处是此组件已经默认了许多交互方式，你只用设置想要的显示模式,JOptionPane 就能轻易的显示出来，可说相当方便，若这些模式还是无法满足你的需求，你就可以使用JDialog来自行设计你的对话框。 我们先来看如何构造JDialog,JOptionPane将在后半段介绍：
上面所说的modal是一种对话框操作模式，当modal为true时，代表用户必须结束对话框才能回到原来所属的窗口。当modal为 false时，代表对话框与所属窗口可以互相切换，彼此之间在操作上没有顺序性。
一般而言对话框都会依附在某个窗口上，例如JFrame或JDialog，原因在于对话框通常是一个程序运行的过程中与用户互动的中 间过程，在使用JDialog上跟JFrame非常相似，由上面的JDialog层次结构图中你可以发现，JDialog是继承AWT的Dialog类而来，因 此JDialog为一个Heavyweight组件。要加入组件到JDialog上与JFrame是一样的，你必须先取得JDialog的ContentPane,然后再把组 件加到此ContentPane中，JDialog默认的版面管理器是BorderLayout.
我们来看一个JDialog的例子，在这个例子中，用户在主窗口按下"借用物品"的按钮时，会跳出一个让用户填写窗体的JDialog 窗口，用户必须结束此JDialog窗口后才能返回主窗口.
import javax.swing.*;
import javax.swing.border.*;
import java.awt.*;
import java.awt.event.*;
import java.util.*;
import com.incors.plaf.alloy.*;
import com.incors.plaf.alloy.themes.glass.*;
public class DialogDemo implements ActionListener {
JFrame f = null;
public void actionPerformed(ActionEvent e) {
String cmd = e.getActionCommand();
if (cmd.equals("借用物品")) {
new LendingSystem(f);
} else if (cmd.equals("离开系统")) {
System.exit(0);
}
}
public DialogDemo() {
f = new JFrame("JDialog Example");
Container contentPane = f.getContentPane();
JPanel buttonPanel = new JPanel();
JButton b = new JButton("借用物品");
b.addActionListener(this);
buttonPanel.add(b);
b = new JButton("离开系统");
b.addActionListener(this);
buttonPanel.add(b);
buttonPanel.setBorder(BorderFactory.createTitledBorder(BorderFactory
.createLineBorder(Color.blue, 2), "借用物品系统",
TitledBorder.CENTER, TitledBorder.TOP));
contentPane.add(buttonPanel, BorderLayout.CENTER);
f.pack();
f.setVisible(true);
f.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
System.exit(0);
}
});
}
public static void main(String[] args) {
SwingUtil.setLookAndFeel();
new DialogDemo();
}
}
class LendingSystem implements ActionListener {
JTextField staffField, objectField, borrowDateField, returnDateField,
reasonField;
JDialog dialog;
public void actionPerformed(ActionEvent e) {
String cmd = e.getActionCommand();
if (cmd.equals("确定")) {
} else if (cmd.equals("取消")) {
dialog.dispose();
}
}
LendingSystem(JFrame f) {
dialog = new JDialog(f, "借用物品", true);
GridBagConstraints c;
int gridx, gridy, gridwidth, gridheight, anchor, fill, ipadx, ipady;
double weightx, weighty;
Insets inset;
GridBagLayout gridbag = new GridBagLayout();
Container dialogPane = dialog.getContentPane();
dialogPane.setLayout(gridbag);
JLabel label = new JLabel("员工编号 : ");
gridx = 0; // 第0列
gridy = 0; // 第0行
gridwidth = 1; // 占一单位宽度
gridheight = 1; // 占一单位高度
weightx = 0; // 窗口增大时组件宽度增大比率0
weighty = 0; // 窗口增大时组件高度增大比率0
anchor = GridBagConstraints.CENTER; // 容器大于组件size时将组件置于容器中央
fill = GridBagConstraints.BOTH; // 窗口拉大时会填满水平与垂直空间
inset = new Insets(0, 0, 0, 0); // 组件间间距
ipadx = 0; // 组件内水平宽度
ipady = 0; // 组件内垂直高度
c = new GridBagConstraints(gridx, gridy, gridwidth, gridheight,
weightx, weighty, anchor, fill, inset, ipadx, ipady);
gridbag.setConstraints(label, c);
dialogPane.add(label);
label = new JLabel("借用器具 : ");
gridx = 3;
gridy = 0;
c = new GridBagConstraints(gridx, gridy, gridwidth, gridheight,
weightx, weighty, anchor, fill, inset, ipadx, ipady);
gridbag.setConstraints(label, c);
dialogPane.add(label);
label = new JLabel("借用日期: ");
gridx = 0;
gridy = 1;
c = new GridBagConstraints(gridx, gridy, gridwidth, gridheight,
weightx, weighty, anchor, fill, inset, ipadx, ipady);
gridbag.setConstraints(label, c);
dialogPane.add(label);
label = new JLabel("归还日期: ");
gridx = 3;
gridy = 1;
c = new GridBagConstraints(gridx, gridy, gridwidth, gridheight,
weightx, weighty, anchor, fill, inset, ipadx, ipady);
gridbag.setConstraints(label, c);
dialogPane.add(label);
label = new JLabel("借用原因 : ");
gridx = 0;
gridy = 2;
c = new GridBagConstraints(gridx, gridy, gridwidth, gridheight,
weightx, weighty, anchor, fill, inset, ipadx, ipady);
gridbag.setConstraints(label, c);
dialogPane.add(label);
staffField = new JTextField();
gridx = 1;
gridy = 0;
gridwidth = 2;
gridheight = 1;
weightx = 1;
weighty = 0;
c = new GridBagConstraints(gridx, gridy, gridwidth, gridheight,
weightx, weighty, anchor, fill, inset, ipadx, ipady);
gridbag.setConstraints(staffField, c);
dialogPane.add(staffField);
objectField = new JTextField();
gridx = 4;
gridy = 0;
c = new GridBagConstraints(gridx, gridy, gridwidth, gridheight,
weightx, weighty, anchor, fill, inset, ipadx, ipady);
gridbag.setConstraints(objectField, c);
dialogPane.add(objectField);
borrowDateField = new JTextField();
gridx = 1;
gridy = 1;
c = new GridBagConstraints(gridx, gridy, gridwidth, gridheight,
weightx, weighty, anchor, fill, inset, ipadx, ipady);
gridbag.setConstraints(borrowDateField, c);
dialogPane.add(borrowDateField);
returnDateField = new JTextField();
gridx = 4;
gridy = 1;
c = new GridBagConstraints(gridx, gridy, gridwidth, gridheight,
weightx, weighty, anchor, fill, inset, ipadx, ipady);
gridbag.setConstraints(returnDateField, c);
dialogPane.add(returnDateField);
reasonField = new JTextField();
gridx = 1;
gridy = 2;
gridwidth = 5;
c = new GridBagConstraints(gridx, gridy, gridwidth, gridheight,
weightx, weighty, anchor, fill, inset, ipadx, ipady);
gridbag.setConstraints(reasonField, c);
dialogPane.add(reasonField);
JPanel panel = new JPanel();
panel.setLayout(new GridLayout(1, 2));
JButton b = new JButton("确定");
panel.add(b);
b = new JButton("取消");
b.addActionListener(this);
panel.add(b);
gridx = 0;
gridy = 3;
gridwidth = 6;
weightx = 1;
weighty = 1;
c = new GridBagConstraints(gridx, gridy, gridwidth, gridheight,
weightx, weighty, anchor, fill, inset, ipadx, ipady);
gridbag.setConstraints(panel, c);
dialogPane.add(panel);
dialog.setBounds(200, 150, 400, 130);
dialog.show();
}
}
class SwingUtil {
public static final void setLookAndFeel() {
try {
Font font = new Font("JFrame", Font.PLAIN, 12);
Enumeration keys = UIManager.getLookAndFeelDefaults().keys();
while (keys.hasMoreElements()) {
Object key = keys.nextElement();
if (UIManager.get(key) instanceof Font) {
UIManager.put(key, font);
}
}
AlloyLookAndFeel.setProperty("alloy.isLookAndFeelFrameDecoration",
"true");
AlloyTheme theme = new GlassTheme();
LookAndFeel alloyLnF = new AlloyLookAndFeel(theme);
UIManager.setLookAndFeel(alloyLnF);
} catch (UnsupportedLookAndFeelException ex) {
ex.printStackTrace();
}
/*
* try{ Font font = new Font("JFrame", Font.PLAIN, 12); Enumeration keys
* = UIManager.getLookAndFeelDefaults().keys();
*
* while (keys.hasMoreElements()) { Object key = keys.nextElement(); if
* (UIManager.get(key) instanceof Font) { UIManager.put(key, font); } }
* UIManager
* .setLookAndFeel("com.stefankrause.xplookandfeel.XPLookAndFeel");
* }catch(Exception e){ e.printStackTrace(); }
*/
}
}