我现在正在学习Swing课程以及它的一切。我已经把这个玩具程序放在一起，提示输入一个名字然后出现一个JOptionPane，上面写着“你输入了（你的名字）”。我只能点击我使用的提交按钮，但我也想让它与Enter按钮一起使用。我已经尝试添加KeyListener，正如我正在使用的Java书中推荐的那样（Eventful Java，Bruce Danyluk和Murtagh）。
这是我的代码：
import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
public class NamePrompt extends JFrame{
private static final long serialVersionUID = 1L;
String name;
public NamePrompt(){
setLayout(new BorderLayout());
JLabel enterYourName = new JLabel("Enter Your Name Here:");
JTextField textBoxToEnterName = new JTextField(21);
JPanel panelTop = new JPanel();
panelTop.add(enterYourName);
panelTop.add(textBoxToEnterName);
JButton submit = new JButton("Submit");
submit.addActionListener(new SubmitButton(textBoxToEnterName));
submit.addKeyListener(new SubmitButton(textBoxToEnterName));
JPanel panelBottom = new JPanel();
panelBottom.add(submit);
//Add panelTop to JFrame
add(panelTop, BorderLayout.NORTH);
add(panelBottom, BorderLayout.SOUTH);
//JFrame set-up
setTitle("Name Prompt Program");
setDefaultCloseOperation(EXIT_ON_CLOSE);
pack();
setLocationRelativeTo(null);
}
public static void main(String[] args) {
NamePrompt promptForName = new NamePrompt();
promptForName.setVisible(true);
}
}
这是actionListener，keyListener类：
import java.awt.Component;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JTextField;
public class SubmitButton implements ActionListener, KeyListener {
JTextField nameInput;
public SubmitButton(JTextField textfield){
nameInput = textfield;
}
@Override
public void actionPerformed(ActionEvent submitClicked) {
Component frame = new JFrame();
JOptionPane.showMessageDialog(frame , "You've Submitted the name " + nameInput.getText());
}
@Override
public void keyPressed(KeyEvent e) {
if (e.getKeyCode()==KeyEvent.VK_ENTER){
System.out.println("Hello");
}
Component frame = new JFrame();
JOptionPane.showMessageDialog(frame , "You've Submitted the name " + nameInput.getText());
}
@Override
public void keyReleased(KeyEvent arg0) {
// TODO Auto-generated method stub
}
@Override
public void keyTyped(KeyEvent arg0) {
}
}
有一个简单的技巧。用所有按钮构造框架后，执行以下操作：
frame.getRootPane().setDefaultButton(submitButton);
对于每个帧，您可以设置一个默认按钮，该按钮将自动侦听Enter键（可能还有其他一些我不知道的事件）。当您在该帧中按Enter键时，ActionListeners将调用它们的actionPerformed()方法。
就我所看到的，你的代码问题在于，每次敲击键时都会弹出对话框，因为你没有把它放在if-body中。尝试将其更改为：
@Override
public void keyPressed(KeyEvent e) {
if (e.getKeyCode()==KeyEvent.VK_ENTER){
System.out.println("Hello");
JOptionPane.showMessageDialog(null , "You've Submitted the name " + nameInput.getText());
}
}
更新：我发现你的代码有什么问题。您正在将键侦听器添加到“提交”按钮而不是TextField。将您的代码更改为：
SubmitButton listener = new SubmitButton(textBoxToEnterName);
textBoxToEnterName.addActionListener(listener);
submit.addKeyListener(listener);
您可以使用顶级容器根窗格来设置默认按钮，这将允许它响应回车。
SwingUtilities.getRootPane(submitButton).setDefaultButton(submitButton);
当然，这假设您已将按钮添加到有效容器中;）
更新
这是使用JRootPane#setDefaultButton和键绑定API的基本示例
public class DefaultButton {
public static void main(String[] args) {
new DefaultButton();
}
public DefaultButton() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
}
JFrame frame = new JFrame("Test");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class TestPane extends JPanel {
private JButton button;
private JLabel label;
private int count;
public TestPane() {
label = new JLabel("Press the button");
button = new JButton("Press me");
setLayout(new GridBagLayout());
GridBagConstraints gbc = new GridBagConstraints();
gbc.gridy = 0;
add(label, gbc);
gbc.gridy++;
add(button, gbc);
gbc.gridy++;
add(new JButton("No Action Here"), gbc);
button.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
doButtonPressed(e);
}
});
InputMap im = button.getInputMap(WHEN_ANCESTOR_OF_FOCUSED_COMPONENT);
ActionMap am = button.getActionMap();
im.put(KeyStroke.getKeyStroke(KeyEvent.VK_SPACE, 0), "spaced");
am.put("spaced", new AbstractAction() {
@Override
public void actionPerformed(ActionEvent e) {
doButtonPressed(e);
}
});
}
@Override
public void addNotify() {
super.addNotify();
SwingUtilities.getRootPane(button).setDefaultButton(button);
}
protected void doButtonPressed(ActionEvent evt) {
count++;
label.setText("Pressed " + count + " times");
}
}
}
当然，这假设具有焦点的组件不消耗有问题的键事件（例如消耗空间的第二个按钮或输入键
在ActionListener类中，您只需添加即可
public void actionPerformed(ActionEvent event) {
if (event.getSource()==textField){
textButton.doClick();
}
else if (event.getSource()==textButton) {
//do something
}
}
switch(KEYEVENT.getKeyCode()){
case KeyEvent.VK_ENTER:
// I was trying to use case 13 from the ascii table.
//Krewn Generated method stub...
break;
}
没有框架这适合我：
JTextField tf = new JTextField(20);
tf.addKeyListener(new KeyAdapter() {
public void keyPressed(KeyEvent e) {
if (e.getKeyCode()==KeyEvent.VK_ENTER){
SwingUtilities.getWindowAncestor(e.getComponent()).dispose();
}
}
});
String[] options = {"Ok", "Cancel"};
int result = JOptionPane.showOptionDialog(
null, tf, "Enter your message",
JOptionPane.OK_CANCEL_OPTION,
JOptionPane.QUESTION_MESSAGE,
null,
options,0);
message = tf.getText();
我知道这不是最好的方法，但是右键单击有问题的按钮，事件，键，键输入。这是一种简单的方法，但对任何键都有反应
textField_in = new JTextField();
textField_in.addKeyListener(new KeyAdapter() {
@Override
public void keyPressed(KeyEvent arg0) {
System.out.println(arg0.getExtendedKeyCode());
if (arg0.getKeyCode()==10) {
String name = textField_in.getText();
textField_out.setText(name);
}
}
});
textField_in.setBounds(173, 40, 86, 20);
frame.getContentPane().add(textField_in);
textField_in.setColumns(10);