mmm estoy ocidado
package swing.comboexample;
import java.util.logging.Logger;
import javax.swing.Action;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import java.awt.FlowLayout;
import java.awt.Color;
import java.awt.event.ActionEvent;
import java.beans.PropertyChangeListener;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.text.AttributeSet.ColorAttribute;
public class HelloWorld
extends JFrame{
public static void main
(String...
args) { HelloWorld helloWorld = new HelloWorld();
helloWorld.
setDefaultCloseOperation(JFrame.
EXIT_ON_CLOSE); JComboBox<String> cboColor = new JComboBox<String>();
cboColor.addItem("rojo");
cboColor.addItem("verde");
cboColor.addItem("azul");
lblPrincipal.setOpaque(true);
cboColor.addActionListener(p->{
int index = cboColor.getSelectedIndex();
switch (index) {
case 1:
lblPrincipal.
setBackground(Color.
RED); break;
case 2:
lblPrincipal.
setBackground(Color.
GREEN ); break;
case 3:
lblPrincipal.
setBackground(Color.
BLUE); break;
}
} );
helloWorld.
getContentPane().
setLayout( new FlowLayout() ); helloWorld.getContentPane().add(cboColor);
helloWorld.getContentPane().add(lblPrincipal);
helloWorld.setLocationRelativeTo(null);
helloWorld.pack();
helloWorld.setVisible(true);
}
}