类 FocusTraversalPolicy 的使用方法
官方说明:
FocusTraversalPolicy 定义一种顺序，按此顺序遍历具有特定焦点循环根的 Component。实例可以将此策略应用于任意焦点循环根，允许它们在整个 Container 共享。当焦点循环根的组件层次结构更改时，不必重新初始化它们。
FocusTraversalPolicy 的核心职责是提供算法，在 UI 中进行向前或向后遍历时确定下一个和上一个要聚焦的 Component。每个 FocusTraversalPolicy 还必须提供算法，确定遍历循环中第一个、最后一个，以及默认的组件。进行正常的正向和反向遍历时，分别使用第一个和最后一个 Component。默认的 Component 是向下遍历到一个新的焦点遍历循环时接收焦点的第一个 Component。FocusTraversalPolicy 可以随意提供确定窗口初始 Component 的算法。初始 Component 是首次将窗口设置为可见时接收焦点的第一个 Component。
import javax.swing.*;
import java.awt.*;
import java.util.*;
import java.awt.event.*;
public class MainFrame extends JFrame {
private static final long serialVersionUID = 1L;
private JPanel jContentPane = null;
private JTextField jTextField = null;
private JTextField jTextField1 = null;
private JTextField jTextField2 = null;
private JTextField jTextField3 = null;
private JTextField jTextField4 = null;
private JTextField jTextField5 = null;
private JTextField jTextField6 = null;
private JTextField jTextField7 = null;
private JTextField jTextField8 = null;
private JTextField jTextField9 = null;
static MyOwnFocusTraversalPolicy newPolicy;
/**
* This method initializes jTextField
*
* @return javax.swing.JTextField
*/
private JTextField getJTextField() {
if (jTextField == null) {
jTextField = new JTextField();
jTextField.setLocation(new Point(37, 30));
jTextField.setSize(new Dimension(200, 22));
jTextField.addActionListener(new MyActionListener());
}
return jTextField;
}
/**
* This method initializes jTextField1
*
* @return javax.swing.JTextField
*/
private JTextField getJTextField1() {
if (jTextField1 == null) {
jTextField1 = new JTextField();
jTextField1.setBounds(new Rectangle(37, 60, 200, 22));
jTextField1.addActionListener(new MyActionListener());
}
return jTextField1;
}
/**
* This method initializes jTextField2
*
* @return javax.swing.JTextField
*/
private JTextField getJTextField2() {
if (jTextField2 == null) {
jTextField2 = new JTextField();
jTextField2.setBounds(new Rectangle(37, 90, 200, 22));
jTextField2.addActionListener(new MyActionListener());
}
return jTextField2;
}
/**
* This method initializes jTextField3
*
* @return javax.swing.JTextField
*/
private JTextField getJTextField3() {
if (jTextField3 == null) {
jTextField3 = new JTextField();
jTextField3.setBounds(new Rectangle(37, 120, 200, 22));
jTextField3.addActionListener(new MyActionListener());
}
return jTextField3;
}
/**
* This method initializes jTextField4
*
* @return javax.swing.JTextField
*/
private JTextField getJTextField4() {
if (jTextField4 == null) {
jTextField4 = new JTextField();
jTextField4.setBounds(new Rectangle(37, 150, 200, 22));
jTextField4.addActionListener(new MyActionListener());
}
return jTextField4;
}
/**
* This method initializes jTextField5
*
* @return javax.swing.JTextField
*/
private JTextField getJTextField5() {
if (jTextField5 == null) {
jTextField5 = new JTextField();
jTextField5.setBounds(new Rectangle(255, 30, 200, 22));
jTextField5.addActionListener(new MyActionListener());
}
return jTextField5;
}
/**
* This method initializes jTextField6
*
* @return javax.swing.JTextField
*/
private JTextField getJTextField6() {
if (jTextField6 == null) {
jTextField6 = new JTextField();
jTextField6.setBounds(new Rectangle(255, 60, 200, 22));
jTextField6.addActionListener(new MyActionListener());
}
return jTextField6;
}
/**
* This method initializes jTextField7
*
* @return javax.swing.JTextField
*/
private JTextField getJTextField7() {
if (jTextField7 == null) {
jTextField7 = new JTextField();
jTextField7.setBounds(new Rectangle(255, 90, 200, 22));
jTextField7.addActionListener(new MyActionListener());
}
return jTextField7;
}
/**
* This method initializes jTextField8
*
* @return javax.swing.JTextField
*/
private JTextField getJTextField8() {
if (jTextField8 == null) {
jTextField8 = new JTextField();
jTextField8.setBounds(new Rectangle(255, 120, 200, 22));
jTextField8.addActionListener(new MyActionListener());
}
return jTextField8;
}
/**
* This method initializes jTextField9
*
* @return javax.swing.JTextField
*/
private JTextField getJTextField9() {
if (jTextField9 == null) {
jTextField9 = new JTextField();
jTextField9.setBounds(new Rectangle(255, 150, 200, 22));
jTextField9.addActionListener(new MyActionListener());
}
return jTextField9;
}
/**
* @param args
*/
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
MainFrame thisClass = new MainFrame();
thisClass.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
thisClass.setVisible(true);
thisClass.setFocusTraversalPolicy(newPolicy);
}
});
}
/**
* This is the default constructor
*/
public MainFrame() {
super();
initialize();
}
/**
* This method initializes this
*
* @return void
*/
private void initialize() {
this.setSize(491, 259);
this.setContentPane(getJContentPane());
this.setTitle("JFrame");
}
/**
* This method initializes jContentPane
*
* @return javax.swing.JPanel
*/
private JPanel getJContentPane() {
if (jContentPane == null) {
jContentPane = new JPanel();
jContentPane.setLayout(null);
jContentPane.add(getJTextField(), null);
jContentPane.add(getJTextField1(), null);
jContentPane.add(getJTextField2(), null);
jContentPane.add(getJTextField3(), null);
jContentPane.add(getJTextField4(), null);
jContentPane.add(getJTextField5(), null);
jContentPane.add(getJTextField6(), null);
jContentPane.add(getJTextField7(), null);
jContentPane.add(getJTextField8(), null);
jContentPane.add(getJTextField9(), null);
Vector<Component> order = new Vector<Component>(10);
order.add(getJTextField());
order.add(getJTextField1());
order.add(getJTextField2());
order.add(getJTextField3());
order.add(getJTextField4());
order.add(getJTextField5());
order.add(getJTextField6());
order.add(getJTextField7());
order.add(getJTextField8());
order.add(getJTextField9());
newPolicy = new MyOwnFocusTraversalPolicy(order);
}
return jContentPane;
}
class MyActionListener implements ActionListener { // 所有文本框都加入此ActionListener
public void actionPerformed(ActionEvent e) {
((JTextField) e.getSource()).transferFocus();// 按【Enter】键,focus往下一个组件
}
}
//内置类，实现TAB按照指定规则设置
public static class MyOwnFocusTraversalPolicy extends FocusTraversalPolicy {
Vector<Component> order;
public MyOwnFocusTraversalPolicy(Vector<Component> order) {
this.order = new Vector<Component>(order.size());
this.order.addAll(order);
}
public Component getComponentAfter(Container focusCycleRoot,
Component aComponent) {
int idx = (order.indexOf(aComponent) + 1) % order.size();
return order.get(idx);
}
public Component getComponentBefore(Container focusCycleRoot,
Component aComponent) {
int idx = order.indexOf(aComponent) - 1;
if (idx < 0) {
idx = order.size() - 1;
}
return order.get(idx);
}
public Component getDefaultComponent(Container focusCycleRoot) {
return order.get(0);
}
public Component getLastComponent(Container focusCycleRoot) {
return order.lastElement();
}
public Component getFirstComponent(Container focusCycleRoot) {
return order.get(0);
}
}
}
import java.awt.*;
import java.util.*;
import java.awt.event.*;
public class MainFrame extends JFrame {
private static final long serialVersionUID = 1L;
private JPanel jContentPane = null;
private JTextField jTextField = null;
private JTextField jTextField1 = null;
private JTextField jTextField2 = null;
private JTextField jTextField3 = null;
private JTextField jTextField4 = null;
private JTextField jTextField5 = null;
private JTextField jTextField6 = null;
private JTextField jTextField7 = null;
private JTextField jTextField8 = null;
private JTextField jTextField9 = null;
static MyOwnFocusTraversalPolicy newPolicy;
/**
* This method initializes jTextField
*
* @return javax.swing.JTextField
*/
private JTextField getJTextField() {
if (jTextField == null) {
jTextField = new JTextField();
jTextField.setLocation(new Point(37, 30));
jTextField.setSize(new Dimension(200, 22));
jTextField.addActionListener(new MyActionListener());
}
return jTextField;
}
/**
* This method initializes jTextField1
*
* @return javax.swing.JTextField
*/
private JTextField getJTextField1() {
if (jTextField1 == null) {
jTextField1 = new JTextField();
jTextField1.setBounds(new Rectangle(37, 60, 200, 22));
jTextField1.addActionListener(new MyActionListener());
}
return jTextField1;
}
/**
* This method initializes jTextField2
*
* @return javax.swing.JTextField
*/
private JTextField getJTextField2() {
if (jTextField2 == null) {
jTextField2 = new JTextField();
jTextField2.setBounds(new Rectangle(37, 90, 200, 22));
jTextField2.addActionListener(new MyActionListener());
}
return jTextField2;
}
/**
* This method initializes jTextField3
*
* @return javax.swing.JTextField
*/
private JTextField getJTextField3() {
if (jTextField3 == null) {
jTextField3 = new JTextField();
jTextField3.setBounds(new Rectangle(37, 120, 200, 22));
jTextField3.addActionListener(new MyActionListener());
}
return jTextField3;
}
/**
* This method initializes jTextField4
*
* @return javax.swing.JTextField
*/
private JTextField getJTextField4() {
if (jTextField4 == null) {
jTextField4 = new JTextField();
jTextField4.setBounds(new Rectangle(37, 150, 200, 22));
jTextField4.addActionListener(new MyActionListener());
}
return jTextField4;
}
/**
* This method initializes jTextField5
*
* @return javax.swing.JTextField
*/
private JTextField getJTextField5() {
if (jTextField5 == null) {
jTextField5 = new JTextField();
jTextField5.setBounds(new Rectangle(255, 30, 200, 22));
jTextField5.addActionListener(new MyActionListener());
}
return jTextField5;
}
/**
* This method initializes jTextField6
*
* @return javax.swing.JTextField
*/
private JTextField getJTextField6() {
if (jTextField6 == null) {
jTextField6 = new JTextField();
jTextField6.setBounds(new Rectangle(255, 60, 200, 22));
jTextField6.addActionListener(new MyActionListener());
}
return jTextField6;
}
/**
* This method initializes jTextField7
*
* @return javax.swing.JTextField
*/
private JTextField getJTextField7() {
if (jTextField7 == null) {
jTextField7 = new JTextField();
jTextField7.setBounds(new Rectangle(255, 90, 200, 22));
jTextField7.addActionListener(new MyActionListener());
}
return jTextField7;
}
/**
* This method initializes jTextField8
*
* @return javax.swing.JTextField
*/
private JTextField getJTextField8() {
if (jTextField8 == null) {
jTextField8 = new JTextField();
jTextField8.setBounds(new Rectangle(255, 120, 200, 22));
jTextField8.addActionListener(new MyActionListener());
}
return jTextField8;
}
/**
* This method initializes jTextField9
*
* @return javax.swing.JTextField
*/
private JTextField getJTextField9() {
if (jTextField9 == null) {
jTextField9 = new JTextField();
jTextField9.setBounds(new Rectangle(255, 150, 200, 22));
jTextField9.addActionListener(new MyActionListener());
}
return jTextField9;
}
/**
* @param args
*/
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
MainFrame thisClass = new MainFrame();
thisClass.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
thisClass.setVisible(true);
thisClass.setFocusTraversalPolicy(newPolicy);
}
});
}
/**
* This is the default constructor
*/
public MainFrame() {
super();
initialize();
}
/**
* This method initializes this
*
* @return void
*/
private void initialize() {
this.setSize(491, 259);
this.setContentPane(getJContentPane());
this.setTitle("JFrame");
}
/**
* This method initializes jContentPane
*
* @return javax.swing.JPanel
*/
private JPanel getJContentPane() {
if (jContentPane == null) {
jContentPane = new JPanel();
jContentPane.setLayout(null);
jContentPane.add(getJTextField(), null);
jContentPane.add(getJTextField1(), null);
jContentPane.add(getJTextField2(), null);
jContentPane.add(getJTextField3(), null);
jContentPane.add(getJTextField4(), null);
jContentPane.add(getJTextField5(), null);
jContentPane.add(getJTextField6(), null);
jContentPane.add(getJTextField7(), null);
jContentPane.add(getJTextField8(), null);
jContentPane.add(getJTextField9(), null);
Vector<Component> order = new Vector<Component>(10);
order.add(getJTextField());
order.add(getJTextField1());
order.add(getJTextField2());
order.add(getJTextField3());
order.add(getJTextField4());
order.add(getJTextField5());
order.add(getJTextField6());
order.add(getJTextField7());
order.add(getJTextField8());
order.add(getJTextField9());
newPolicy = new MyOwnFocusTraversalPolicy(order);
}
return jContentPane;
}
class MyActionListener implements ActionListener { // 所有文本框都加入此ActionListener
public void actionPerformed(ActionEvent e) {
((JTextField) e.getSource()).transferFocus();// 按【Enter】键,focus往下一个组件
}
}
//内置类，实现TAB按照指定规则设置
public static class MyOwnFocusTraversalPolicy extends FocusTraversalPolicy {
Vector<Component> order;
public MyOwnFocusTraversalPolicy(Vector<Component> order) {
this.order = new Vector<Component>(order.size());
this.order.addAll(order);
}
public Component getComponentAfter(Container focusCycleRoot,
Component aComponent) {
int idx = (order.indexOf(aComponent) + 1) % order.size();
return order.get(idx);
}
public Component getComponentBefore(Container focusCycleRoot,
Component aComponent) {
int idx = order.indexOf(aComponent) - 1;
if (idx < 0) {
idx = order.size() - 1;
}
return order.get(idx);
}
public Component getDefaultComponent(Container focusCycleRoot) {
return order.get(0);
}
public Component getLastComponent(Container focusCycleRoot) {
return order.lastElement();
}
public Component getFirstComponent(Container focusCycleRoot) {
return order.get(0);
}
}
}
本程序还可以实现按键盘【Enter】键循环遍历所有文本框。
