Java Swing FocusTraversalPolicy问题

Java Swing FocusTraversalPolicy Issue

我目前在实现FocusTraversalPolicy时遇到问题。

我想使用Tab / Shift+Tab键盘快捷键来浏览上下/左右。填写表格时，这将使导航更简单。

该策略应仅影响JFrame的mainPanel中的所有元素。

我已经使用以下类别实施了该政策：

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public class DefaultViewFocusTraversalPolicy
extends FocusTraversalPolicy
{
ArrayList<Component> order;

public DefaultViewFocusTraversalPolicy(ArrayList<Component> order)
{
this.order = order;
}

@Override
public Component getComponentAfter(Container aContainer, Component aComponent)
{
int index = (order.indexOf(aComponent) + 1) % order.size();
Component after = order.get(index);
while (index < order.size() && !(after.isEnabled() && after.isVisible()))
{
index++;
after = order.get(index);
}
return after;
}

@Override
public Component getComponentBefore(Container aContainer, Component aComponent)
{
int index = order.indexOf(aComponent) - 1;
if (index < 0)
{
index = order.size() - 1;
}
Component before = order.get(index);
while (index >= 0 && !(before.isEnabled() && before.isVisible()))
{
index--;
before = order.get(index);
}
return before;
}

@Override
public Component getFirstComponent(Container aContainer)
{
int index = 0;
Component first = order.get(index);
while (index < order.size() && !(first.isEnabled() && first.isVisible()))
{
index++;
first = order.get(index);
}
return first;
}

@Override
public Component getLastComponent(Container aContainer)
{
int index = order.size() - 1;
Component last = order.get(index);
while (index >= 0 && !(last.isEnabled() && last.isVisible()))
{
index--;
last = order.get(index);
}
return last;
}

@Override
public Component getDefaultComponent(Container aContainer)
{
return getFirstComponent(aContainer);
}
}

然后，在我的视图的构造函数(例如main JFrame)中使用以下实例化该类：

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ArrayList<Component> order = new ArrayList<>();
order.add(this.ecmID);
order.add(this.modeID);
// ...
DefaultViewFocusTraversalPolicy policy =
new DefaultViewFocusTraversalPolicy(order);
this.mainPanel.setFocusTraversalPolicy(policy);

但是，当我尝试使用Tab键浏览元素时，没有任何变化，并且以前的策略仍然存在。我已经尝试过Java教程：link

任何帮助将不胜感激。

相关讨论

1	ArrayList<Component> order = new ArrayList<>();

我认为您正在寻找

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import java.awt.Component;
import java.awt.Container;
import java.awt.FocusTraversalPolicy;
import java.awt.GridLayout;
import java.awt.KeyEventDispatcher;
import java.awt.KeyboardFocusManager;
import java.awt.event.KeyEvent;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;

public class Testing {

private static final long serialVersionUID = 1L;
private Component[] focusList;
private int focusNumber = 0;
private JFrame frame;

public Testing() {
JTextField tf1 = new JTextField(5);
tf1.setName("tf1");
JTextField tf2 = new JTextField(5);
tf2.setName("tf2");
JTextField tf3 = new JTextField(5);
tf3.setName("tf3");
JButton b1 = new JButton("B1");
b1.setName("b1");
JButton b2 = new JButton("B2");
b2.setName("b2");
tf2.setEnabled(false);
focusList = new Component[]{tf1, b1, tf2, b2, tf3};
JPanel panel = new JPanel(new GridLayout(5, 1));
panel.add(tf1);
panel.add(b1);
panel.add(tf2);
panel.add(b2);
panel.add(tf3);
frame = new JFrame();
frame.setFocusTraversalPolicy(new MyFocusTraversalPolicy());
frame.add(panel);
frame.pack();
frame.setLocation(150, 100);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
KeyboardFocusManager.getCurrentKeyboardFocusManager().addKeyEventDispatcher(new KeyEventDispatcher() {
@Override
public boolean dispatchKeyEvent(KeyEvent ke) {
if (ke.getID() == KeyEvent.KEY_PRESSED) {
if (ke.getKeyCode() == KeyEvent.VK_TAB) {
Component comp = KeyboardFocusManager.getCurrentKeyboardFocusManager().getFocusOwner();
System.out.println(comp.getName());
if (comp.isEnabled() == false) {
if (ke.isShiftDown()) {
KeyboardFocusManager.getCurrentKeyboardFocusManager().focusPreviousComponent();
} else {
KeyboardFocusManager.getCurrentKeyboardFocusManager().focusNextComponent();
}
}
}
}
return false;
}
});
}

private class MyFocusTraversalPolicy extends FocusTraversalPolicy {

@Override
public Component getComponentAfter(Container focusCycleRoot, Component aComponent) {
focusNumber = (focusNumber + 1) % focusList.length;
return focusList[focusNumber];
}

@Override
public Component getComponentBefore(Container focusCycleRoot, Component aComponent) {
focusNumber = (focusList.length + focusNumber - 1) % focusList.length;
return focusList[focusNumber];
}

@Override
public Component getDefaultComponent(Container focusCycleRoot) {
return focusList[0];
}

@Override
public Component getLastComponent(Container focusCycleRoot) {
return focusList[focusList.length - 1];
}

@Override
public Component getFirstComponent(Container focusCycleRoot) {
return focusList[0];
}
}

public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
Testing testing = new Testing();
}
});
}
}