public class KL implements KeyListener {
public static void main(String[] args) {
final JPopupMenu popup = new JPopupMenu();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(300, 200);
frame.setVisible(true);
}
@Override
public void keyPressed(KeyEvent arg0) {
System.out.println(arg0.getKeyChar());
}
@Override
public void keyReleased(KeyEvent e) {
System.out.println(e.getKeyChar());
}
@Override
public void keyTyped(KeyEvent e) {
System.out.println(e.getKeyChar());
}
}
那是我的课,这可能是我真正愚蠢的事情,但我的KeyListener不起作用。控制台上没有任何内容。
答案 0 :(得分:2)
让我们从你没有把听众附加到任何事情的事实开始,然后继续讨论你真正应该使用Key Bindings
的事实并附带示例
import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.awt.event.ActionEvent;
import java.awt.event.KeyEvent;
import javax.swing.AbstractAction;
import javax.swing.ActionMap;
import javax.swing.InputMap;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.KeyStroke;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class TestTableEditing {
public static void main(String[] args) {
new TestTableEditing();
}
public TestTableEditing() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
}
JFrame frame = new JFrame("Testing");
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 JLabel key;
private int counter = 0;
public TestPane() {
key = new JLabel("...");
add(key);
InputMap im = getInputMap(WHEN_IN_FOCUSED_WINDOW);
ActionMap am = getActionMap();
im.put(KeyStroke.getKeyStroke(KeyEvent.VK_A, 0), "A.pressed");
am.put("A.pressed", new AbstractAction() {
@Override
public void actionPerformed(ActionEvent e) {
System.out.println("A was pressed");
key.setText("A was pressed " + (++counter));
}
});
}
}
}
答案 1 :(得分:0)
我知道这是一个很老的帖子,但我想把它放在网上,所以像我这样的人可以找到它......
我在解决这个问题之前已经解决了这个问题几个小时。确保您的Component具有焦点。例如,我将所有活动都放在名为SpaceShipPanel的自定义JPanel中:
class SpaceShipPanel
{
//instance variables
//Now my constructor
SpaceShipPanel(){
//bla bla blah
setFocusable(true);//THIS LINE IS WHAT SAVED ME!!
}
}
据我所知,keyBindings是最好的路线,但我所采用的课程并没有涵盖这个主题。希望这可以节省几个小时的时间撞墙。