如何通过按 Enter 跨越 JTextField 到下一个 JTextField [英] How to across JTextField to next JTextField by hit Enter
问题描述
When select check box to set enable(false) on second text field and hit enter need to focus at third text field
如果未选中任何复选框，则按 ENTER 可以将焦点放在文本字段上作为流程.我应该添加任何代码或如何使其工作
When select check box to set enable(false) on second text field and hit enter need to focus at third text field
if not select any check box then hit ENTER it can be focus on text field as flow.
I should add any code or how can I make it work
我的图形用户界面:
private void chk1ActionPerformed(java.awt.event.ActionEvent evt) {
// Set action perform for check box:
if(chk1.isSelected()){
p1.setEnabled(false);
} else{
p1.setEnabled(true);
}
}
private void chk2ActionPerformed(java.awt.event.ActionEvent evt) {
// Set action perform for check box:
if(chk2.isSelected()){
p2.setEnabled(false);
} else{
p2.setEnabled(true);
}
}
private void chk3ActionPerformed(java.awt.event.ActionEvent evt) {
// Set action perform for check box:
if(chk3.isSelected()){
p3.setEnabled(false);
} else{
p3.setEnabled(true);
}
}
private void p_numKeyPressed(java.awt.event.KeyEvent evt) {
// TODO add your handling code here:
if(evt.getKeyCode()==KeyEvent.VK_ENTER){
p1.requestFocus();
}
}
private void p1KeyPressed(java.awt.event.KeyEvent evt) {
// TODO add your handling code here:
if(evt.getKeyCode()==KeyEvent.VK_ENTER){
p2.requestFocus();
}
}
private void p2KeyPressed(java.awt.event.KeyEvent evt) {
// TODO add your handling code here:
if(evt.getKeyCode()==KeyEvent.VK_ENTER){
p3.requestFocus();
}
}
推荐答案
我认为您正在寻找的是 焦点子系统.这负责按焦点遍历键时组件获得焦点的顺序.例如，您可以定义组件获得焦点的顺序，并添加检查以仅将焦点转移到启用的组件.您似乎还想做的是添加 ENTER 键作为焦点遍历键(即按下它时，焦点将转移到另一个组件 - 根据当前的焦点遍历策略).所有这些都可以通过焦点子系统完成.
I think what you are looking for is the Focus Subsystem. This is responsible for the order in which components are getting focus when you press a focus traversal key. For example you can define what is the order of the components to get focus, and also add the check to transfer focus only to enabled components. What you also seem to want to do is to add the ENTER key as a focus traversal key (ie when pressing it, the focus will be transfered to another component - according to the current focus traversal policy). All this can be done via the focus subsystem.
通过使用焦点子系统，以下代码似乎可以满足您的要求:
The following code seems to do what you are asking, by utilizing the focus subsystem:
import java.awt.Component;
import java.awt.Container;
import java.awt.DefaultFocusTraversalPolicy;
import java.awt.GridLayout;
import java.awt.KeyboardFocusManager;
import java.awt.event.KeyEvent;
import java.util.HashSet;
import java.util.Set;
import javax.swing.JButton;
import javax.swing.JCheckBox;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.KeyStroke;
import javax.swing.SwingUtilities;
public class FocusHopSystem {
public static class AbsoluteFocusTraversalPolicy extends DefaultFocusTraversalPolicy {
private final Component[] comps;
public AbsoluteFocusTraversalPolicy(final Component... comps) {
this.comps = comps.clone();
}
private int indexOf(final Component comp) {
for (int i = 0; i < comps.length; ++i)
if (comps[i] == comp)
return i;
return -1;
}
@Override
public Component getComponentAfter(final Container aContainer, final Component aComponent) {
final int aIndex = indexOf(aComponent);
if (aIndex < 0)
return null;
for (int i = 1; i < comps.length; ++i) {
final Component after = comps[(aIndex + i) % comps.length];
if (after != null && after.isDisplayable() && after.isVisible() && after.isEnabled())
return after;
}
return null;
}
@Override
public Component getComponentBefore(final Container aContainer, final Component aComponent) {
final int aIndex = indexOf(aComponent);
if (aIndex < 0)
return null;
for (int i = 1; i < comps.length; ++i) {
final Component before = comps[(aIndex - i + comps.length) % comps.length];
if (before != null && before.isDisplayable() && before.isVisible() && before.isEnabled())
return before;
}
return null;
}
@Override
public Component getFirstComponent(final Container aContainer) {
for (int i = 0; i < comps.length; ++i) {
final Component first = comps[i];
if (first != null && first.isDisplayable() && first.isVisible() && first.isEnabled())
return first;
}
return null;
}
@Override
public Component getLastComponent(final Container aContainer) {
for (int i = comps.length - 1; i >= 0; --i) {
final Component last = comps[i];
if (last != null && last.isDisplayable() && last.isVisible() && last.isEnabled())
return last;
}
return null;
}
@Override
public Component getDefaultComponent(final Container aContainer) {
return getFirstComponent(aContainer);
}
}
private static void createAndShowGUI() {
final String text = "0";
final int width = 12;
final JTextField tf1 = new JTextField(text, width),
tf2 = new JTextField(text, width),
tf3 = new JTextField(text, width),
tf4 = new JTextField(text, width);
final JCheckBox ck2 = new JCheckBox("jTextField2", true),
ck3 = new JCheckBox("jTextField3", true),
ck4 = new JCheckBox("jTextField4", true);
final JButton save = new JButton("Save");
ck2.addActionListener(e -> tf2.setEnabled(ck2.isSelected()));
ck3.addActionListener(e -> tf3.setEnabled(ck3.isSelected()));
ck4.addActionListener(e -> tf4.setEnabled(ck4.isSelected()));
final JPanel frameContents = new JPanel(new GridLayout(0, 5, 5, 5));
//First row:
frameContents.add(new JPanel());
frameContents.add(ck2);
frameContents.add(ck3);
frameContents.add(ck4);
frameContents.add(new JPanel());
//Second row:
frameContents.add(tf1);
frameContents.add(tf2);
frameContents.add(tf3);
frameContents.add(tf4);
frameContents.add(save);
//Make the other components unfocusable:
for (final Component comp: new Component[]{ck2, ck3, ck4, save})
comp.setFocusable(false);
//Make frameContents the focus cycle root:
frameContents.setFocusCycleRoot(true);
//Install our FocusTraversalPolicy to the cycle root:
frameContents.setFocusTraversalPolicy(new AbsoluteFocusTraversalPolicy(tf1, tf2, tf3, tf4));
//Add KeyEvent.VK_ENTER key to the focus traversal keys of the frameContents:
final Set forwardKeys = frameContents.getFocusTraversalKeys(KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS);
final Set newForwardKeys = new HashSet(forwardKeys);
newForwardKeys.add(KeyStroke.getKeyStroke(KeyEvent.VK_ENTER, 0));
frameContents.setFocusTraversalKeys(KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS, newForwardKeys);
final JFrame frame = new JFrame("Focus traversal test.");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(frameContents);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
//Start focus on the first text field:
tf1.requestFocusInWindow();
}
public static void main(final String[] args) {
SwingUtilities.invokeLater(FocusHopSystem::createAndShowGUI);
}
}
在上面的示例中，除了 TAB 之外，我添加了键 ENTER 作为替代焦点遍历键.
In the above example, I am adding the key ENTER as an alternative focus traversal key, aside from TAB.
正如我发现的那样，它比第一个示例代码更简单，这是因为默认的焦点遍历策略会执行您的要求，即仅允许可聚焦和启用的组件以所需的顺序获得焦点.所以我们只需要将不需要的组件设置为不可聚焦(即复选框和按钮)并启用文本字段.只需添加/设置 ENTER 键作为焦点遍历键即可:
As I found out, it's even simpler than the first sample code, and that's because the default focus traversal policy does what you are asking, ie allows only focusable-and-enabled components to gain focus and in the desired order. So we only need to make the unneeded components to non-focusable (ie the check-boxes and the button) and leave enabled the text-fields. Just add/set the ENTER key as a focus traversal key and you are good to go:
import java.awt.Component;
import java.awt.GridLayout;
import java.awt.KeyboardFocusManager;
import java.awt.event.KeyEvent;
import java.util.HashSet;
import java.util.Set;
import javax.swing.JButton;
import javax.swing.JCheckBox;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.KeyStroke;
import javax.swing.SwingUtilities;
public class FocusHopSystem2 {
private static void createAndShowGUI() {
final String text = "0";
final int width = 12;
final JTextField tf1 = new JTextField(text, width),
tf2 = new JTextField(text, width),
tf3 = new JTextField(text, width),
tf4 = new JTextField(text, width);
final JCheckBox ck2 = new JCheckBox("jTextField2", true),
ck3 = new JCheckBox("jTextField3", true),
ck4 = new JCheckBox("jTextField4", true);
final JButton save = new JButton("Save");
ck2.addActionListener(e -> tf2.setEnabled(ck2.isSelected()));
ck3.addActionListener(e -> tf3.setEnabled(ck3.isSelected()));
ck4.addActionListener(e -> tf4.setEnabled(ck4.isSelected()));
final JPanel frameContents = new JPanel(new GridLayout(0, 5, 5, 5));
//First row:
frameContents.add(new JPanel());
frameContents.add(ck2);
frameContents.add(ck3);
frameContents.add(ck4);
frameContents.add(new JPanel());
//Second row:
frameContents.add(tf1);
frameContents.add(tf2);
frameContents.add(tf3);
frameContents.add(tf4);
frameContents.add(save);
//Make the other components unfocusable:
for (final Component comp: new Component[]{ck2, ck3, ck4, save})
comp.setFocusable(false);
//Make frameContents the focus cycle root:
frameContents.setFocusCycleRoot(true);
////Install the DefaultFocusTraversalPolicy to the cycle root:
//frameContents.setFocusTraversalPolicy(new DefaultFocusTraversalPolicy()); //This is not necessary in this case.
//Add KeyEvent.VK_ENTER key to the focus traversal keys of the frameContents:
final Set forwardKeys = frameContents.getFocusTraversalKeys(KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS);
final Set newForwardKeys = new HashSet(forwardKeys);
newForwardKeys.add(KeyStroke.getKeyStroke(KeyEvent.VK_ENTER, 0));
frameContents.setFocusTraversalKeys(KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS, newForwardKeys);
final JFrame frame = new JFrame("Focus traversal test.");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(frameContents);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
//Start focus on the first text field:
tf1.requestFocusInWindow();
}
public static void main(final String[] args) {
SwingUtilities.invokeLater(FocusHopSystem2::createAndShowGUI);
}
}
您还可以阅读AWT 焦点子系统.
You may also read The AWT Focus Subsystem.
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