I have a bunch of labels in a single frame which basically serves as a multi-line output for displaying text. At certain points of the program the user needs select a option from a given choices. The way they do this is by clicking on the appropriate JLabel.
I tried with a JLabel array, but the functions do not work. I then made a separate ActionEvent for each JLabel, which works, but is there a elegant or efficient code for this?
youre welcome.
you described your problem and i think i can follow.
you could figure out the similarites the ActionListener
s have and put those similarities into a super
-Class
for me, another possibility seems to be an 'all-in-one' ActionListener
. its actionPerformed
-Method has got a paramter of type ActionEvent
. this ActionEvent
provides a getSource()
-Method, you can retrieve the JComponent
the ActionEvent
occured on. so if you give names to your JLabel
s, you can check for the name(s) in the actionPerformed
-Method
Edit
like this way:
public void actionPerformed(final ActionEvent actionEvent) {
final String name = ((JComponent) actionEvent.getSource()).getName();
switch (name) {
case "label1":
handleLabel1();
break;
case "label2":
handleLabel2();
break;
case "label3":
handleLabel3();
break;
default:
break;
}
}
Edit 1
import java.awt.AWTEvent;
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import javax.swing.BoxLayout;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.SwingUtilities;
import javax.swing.WindowConstants;
public class Application extends JFrame {
private abstract class MyComponentListener implements MouseListener, ActionListener {
protected void actionOnButton(final AWTEvent e) {
final JButton button = (JButton) e.getSource();
switch (button.getName()) {
case "button1":
System.out.println("Hello World");
break;
default:
System.out.println("mouse button one clicked on " + button.getName());
break;
}
// more general
this.actionOnComponent(e);
}
protected void actionOnComponent(final AWTEvent e) {
final JComponent component = (JComponent) e.getSource();
final int index = Integer.valueOf(component.getName().replaceAll("[^0-9]", "")).intValue();
switch (index) {
case 1:
System.out.println("Hello World");
break;
default:
System.out.println("mouse button one clicked on " + component.getName());
break;
}
}
protected void actionOnLabel(final AWTEvent e) {
final JLabel label = (JLabel) e.getSource();
switch (label.getName()) {
case "label1":
System.out.println("Hello World");
break;
default:
System.out.println("mouse button one clicked on " + label.getName());
break;
}
// more general
this.actionOnComponent(e);
}
}
private class MyListener extends MyComponentListener {
/**
* {@link ActionListener#actionPerformed(ActionEvent)}
*/
@Override
public void actionPerformed(final ActionEvent e) {
System.out.println("next line(s) generated by ActionListener");
this.actionOnButton(e);
}
@Override
public void mouseClicked(final MouseEvent e) {
// whole process of mouse button down and up
if ((e.getButton() == 1)) {
System.out.println("next line(s) generated by MouseListener");
if ((e.getSource() instanceof JLabel)) {
this.actionOnLabel(e);
} else if (e.getSource() instanceof JButton) {
this.actionOnButton(e);
}
}
}
@Override
public void mouseEntered(final MouseEvent e) {
// on mouse over
}
@Override
public void mouseExited(final MouseEvent e) {
// on mouse out
}
@Override
public void mousePressed(final MouseEvent e) {
// mouse button down
}
@Override
public void mouseReleased(final MouseEvent e) {
// mouse button up after down
}
}
private static final long serialVersionUID = 1L;
private Application() {
super();
}
public void start() {
this.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
this.getContentPane().setLayout(new BoxLayout(this.getContentPane(), BoxLayout.PAGE_AXIS));
this.addLabel("Hello World - Label", "label1");
this.addLabel("Label 2", "label2");
this.addLabel("Label 3", "label3");
this.addButton("Hello Word - Button", "button1");
this.addButton("Button 2", "button2");
final Dimension dimension = new Dimension(500, 150);
this.setSize(dimension);
this.setPreferredSize(dimension);
this.setVisible(true);
}
private void addButton(final String text, final String name) {
final JButton button = new JButton(text);
button.setName(name);
button.addMouseListener(new MyListener());
button.addActionListener(new MyListener());
this.getContentPane().add(button);
}
private void addLabel(final String text, final String name) {
final JLabel label = new JLabel(text);
label.setName(name);
label.addMouseListener(new MyListener());
this.getContentPane().add(label);
}
public static void main(final String[] args) {
final Application app = new Application();
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
app.start();
}
});
}
}