Sun推JavaFX,RIA之战进入白热化(2)

[收藏此页] [打印]

作者：IT168 seasky 2007-11-02

内容导航：

探索JavaFX语言 – 声明语法

第1页：探索JavaFX语言 – 声明语法第2页：执行JavaFX程序第3页： Java类、对象和自动数据绑定第4页：触发器和静态类型

源代码下载

Sun推JavaFX,RIA之战进入白热化(1)

【IT168 专稿】

六、探索JavaFX语言 – 声明语法

Sun打算让JavaFX提供比Java更多的快速用户接口开发功能。同时，这个脚本语言可

以被使用在应用需要的各个方面。在本文的例子中使用JavaFX开发了一个用户接口，一个登录窗口。本例还使用了Java程序实现了同一个登录窗口。这两个文件的代码如下：

用JavaFX实现的登录窗口代码：

import javafx.ui.*;
Frame {
title:  "Authenticate Please"
    width:  300
    height:  125
    visible: true
    content: GridBagPanel {
border: EmptyBorder {
top: 5
                            left: 5
                            bottom: 5
                            right: 5}
cells: [GridCell {
anchor: EAST
gridx: 0
                            gridy: 0
                            insets: {top: 2}
content: SimpleLabel {text: "Username: "}},
GridCell {
anchor: WEST
fill: HORIZONTAL
weightx: 1
                            gridx: 1
                            gridy: 0
                            content: TextField {}},
GridCell {
anchor: EAST
gridx: 0
                            gridy: 1
                            insets: {top: 2}
content: SimpleLabel {text: "PasswordField: "}},
GridCell {
anchor: WEST
fill: HORIZONTAL
gridx: 1
                            gridy: 1
                            weightx: 1
                            content: PasswordField {}},
GridCell {
gridx: 1
                            gridy: 2
                            content:  Button {text: "Login"}}]}
}

用Java实现同样的登录窗口的代码：

public class Login extends javax.swing.JFrame {
/** Creates new form Login */
    public Login() {
initComponents();
}
// <editor-fold defaultstate="collapsed" desc=" Generated Code ">                          
    private void initComponents() {
usernameField = new javax.swing.JTextField();
usernameLabel = new javax.swing.JLabel();
passwordLabel = new javax.swing.JLabel();
passwordField = new javax.swing.JPasswordField();
loginButton = new javax.swing.JButton();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
setTitle("Authenticate Please");
setName("loginFrame");
usernameField.setColumns(15);
usernameLabel.setText("Username:");
passwordLabel.setText("Password:");
passwordLabel.setRequestFocusEnabled(false);
passwordLabel.getAccessibleContext().setAccessibleName("Password:");
loginButton.setLabel("Login");
org.jdesktop.layout.GroupLayout layout = new org.jdesktop.layout.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(org.jdesktop.layout.GroupLayout.LEADING)
.add(layout.createSequentialGroup()
.add(layout.createParallelGroup(org.jdesktop.layout.GroupLayout.LEADING)
.add(layout.createSequentialGroup()
.addContainerGap()
.add(layout.createParallelGroup(org.jdesktop.layout.GroupLayout.LEADING)
.add(org.jdesktop.layout.GroupLayout.TRAILING, layout.createSequentialGroup()
.add(usernameLabel)
.add(19, 19, 19))
.add(layout.createSequentialGroup()
.add(passwordLabel)
.add(23, 23, 23)))
.add(layout.createParallelGroup(org.jdesktop.layout.GroupLayout.LEADING, false)
.add(passwordField)
.add(usernameField)))
.add(layout.createSequentialGroup()
.add(147, 147, 147)
.add(loginButton)))
.addContainerGap(92, Short.MAX_VALUE))
);
layout.setVerticalGroup(
layout.createParallelGroup(org.jdesktop.layout.GroupLayout.LEADING)
.add(layout.createSequentialGroup()
.addContainerGap()
.add(layout.createParallelGroup(org.jdesktop.layout.GroupLayout.BASELINE)
.add(usernameField, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE, org.jdesktop.layout.GroupLayout.DEFAULT_SIZE, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE)
.add(usernameLabel))
.addPreferredGap(org.jdesktop.layout.LayoutStyle.RELATED)
.add(layout.createParallelGroup(org.jdesktop.layout.GroupLayout.BASELINE)
.add(passwordLabel)
.add(passwordField, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE, org.jdesktop.layout.GroupLayout.DEFAULT_SIZE, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE))
.addPreferredGap(org.jdesktop.layout.LayoutStyle.RELATED, 19, Short.MAX_VALUE)
.add(loginButton)
.addContainerGap())
);
pack();
}// </editor-fold>                        

/**
* @param args the command line arguments
*/
    public static void main(String args[]) {
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new Login().setVisible(true);
}
});
}
// Variables declaration - do not modify                     
    private javax.swing.JButton loginButton;
private javax.swing.JPasswordField passwordField;
private javax.swing.JLabel passwordLabel;
private javax.swing.JTextField usernameField;
private javax.swing.JLabel usernameLabel;
// End of variables declaration                   

}

从上面的代码可以看出，JavaFX和传统的Java代码有些类似的地方，如类名上，但从总体结构上看还是有很大的差别。图5显示了这两种方式建立的登录窗口，上面的是用JavaFX建立的，下面的是用传统的Java代码建立的。

图5 登录窗口:

这个小例子很清楚地揭示了JavaFX和传统的Java的第一个主要的不同。JavaFX使用了类似于HTML的语法形式来建立用户接口。在JavaFX的语法中，开发人员只是定义了应该显示些什么东西，而不是用程序来指定需要如何建立。很显然，象JavaFX风格（有时这种风格也叫做声明语法）的语法更容易建立维护。

当然，在JavaFX中也可以使用类似于Java的方式来建立相同的登录窗口。如下面的代码所示：

import javafx.ui.*;
var frame = new Frame();
frame.title = "Authenticate Please";
frame.width = 300;
frame.height = 125;
var panel = new GridBagPanel();
var border = new EmptyBorder();
border.bottom=5;
border.top=5;
border.left=5;
border.right=5;
panel.border = border;
var inset = new Insets();
inset.top=2;
var gcUserLabel = new GridCell();
gcUserLabel.anchor = EAST;
gcUserLabel.gridx=0;
gcUserLabel.gridy=0;
gcUserLabel.insets=inset;
var usernameLabel = new SimpleLabel();
usernameLabel.text = "Username:  ";
gcUserLabel.content = usernameLabel;
var gcUserField = new GridCell();
gcUserField.anchor = WEST;
gcUserField.fill=HORIZONTAL;
gcUserField.weightx=1;
gcUserField.gridx=1;
gcUserField.gridy=0;
gcUserField.insets=inset;
gcUserField.content = new TextField();
var gcPassLabel = new GridCell();
gcPassLabel.anchor = EAST;
gcPassLabel.gridx=0;
gcPassLabel.gridy=1;
gcPassLabel.insets=inset;
var passwordLabel = new SimpleLabel();
passwordLabel.text = "Password:  ";
gcPassLabel.content = passwordLabel;
var gcPassField = new GridCell();
gcPassField.anchor = WEST;
gcPassField.fill=HORIZONTAL;
gcPassField.weightx=1;
gcPassField.gridx=1;
gcPassField.gridy=1;
gcPassField.insets=inset;
gcPassField.content = new PasswordField();
var gcButton = new GridCell();
gcButton.gridx=1;
gcButton.gridy=2;
var loginButton = new Button();
loginButton.text = "Login";
gcButton.content = loginButton;
panel.cells = [gcUserLabel, gcUserField, gcPassLabel, gcPassField, gcButton];
frame.visible = true;
frame.content = panel;

1 2 3 4

【内容导航】

第1页：探索JavaFX语言 – 声明语法	第2页：执行JavaFX程序
第3页： Java类、对象和自动数据绑定	第4页：触发器和静态类型

[责任编辑：李宁]

[an error occurred while processing this directive]