I have a jcombobox containing item1 and item2, also I have a jtextfield.. when I select item1 on my jcombobox I want 30 to appear on my jtextfield while 40 if Item2 was selected... How do I do that?
this is how you do it with ActionLIstener
import java.awt.FlowLayout;
import java.awt.event.*;
import javax.swing.*;
public class MyWind extends JFrame{
public MyWind() {
initialize();
}
private void initialize() {
setSize(300, 300);
setLayout(new FlowLayout(FlowLayout.LEFT));
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
final JTextField field = new JTextField();
field.setSize(200, 50);
field.setText(" ");
JComboBox comboBox = new JComboBox();
comboBox.setEditable(true);
comboBox.addItem("item1");
comboBox.addItem("item2");
//
// Create an ActionListener for the JComboBox component.
//
comboBox.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent event) {
//
// Get the source of the component, which is our combo
// box.
//
JComboBox comboBox = (JComboBox) event.getSource();
Object selected = comboBox.getSelectedItem();
if(selected.toString().equals("item1"))
field.setText("30");
else if(selected.toString().equals("item2"))
field.setText("40");
}
});
getContentPane().add(comboBox);
getContentPane().add(field);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
new MyWind().setVisible(true);
}
});
}
}
The simple solution would be to use a ItemListener
. When the state changes, you would simply check the currently selected item and set the text accordingly
import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class TestComboBox06 {
public static void main(String[] args) {
new TestComboBox06();
}
public TestComboBox06() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException ex) {
} catch (InstantiationException ex) {
} catch (IllegalAccessException ex) {
} catch (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 JComboBox cb;
private JTextField field;
public TestPane() {
cb = new JComboBox(new String[]{"Item 1", "Item 2"});
field = new JTextField(12);
add(cb);
add(field);
cb.setSelectedItem(null);
cb.addItemListener(new ItemListener() {
@Override
public void itemStateChanged(ItemEvent e) {
Object item = cb.getSelectedItem();
if ("Item 1".equals(item)) {
field.setText("20");
} else if ("Item 2".equals(item)) {
field.setText("30");
}
}
});
}
}
}
A better solution would be to create a custom object that represents the value to be displayed and the value associated with it...
Updated
Now I no longer have a 10 month chewing on my ankles, I updated the example to use a ListCellRenderer
which is a more correct approach then been lazy and overriding toString
import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.EventQueue;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import javax.swing.DefaultListCellRenderer;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JList;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class TestComboBox06 {
public static void main(String[] args) {
new TestComboBox06();
}
public TestComboBox06() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException ex) {
} catch (InstantiationException ex) {
} catch (IllegalAccessException ex) {
} catch (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 JComboBox cb;
private JTextField field;
public TestPane() {
cb = new JComboBox(new Item[]{
new Item("Item 1", "20"),
new Item("Item 2", "30")});
cb.setRenderer(new ItemCelLRenderer());
field = new JTextField(12);
add(cb);
add(field);
cb.setSelectedItem(null);
cb.addItemListener(new ItemListener() {
@Override
public void itemStateChanged(ItemEvent e) {
Item item = (Item)cb.getSelectedItem();
field.setText(item.getValue());
}
});
}
}
public class Item {
private String value;
private String text;
public Item(String text, String value) {
this.text = text;
this.value = value;
}
public String getText() {
return text;
}
public String getValue() {
return value;
}
}
public class ItemCelLRenderer extends DefaultListCellRenderer {
@Override
public Component getListCellRendererComponent(JList<?> list, Object value, int index, boolean isSelected, boolean cellHasFocus) {
super.getListCellRendererComponent(list, value, index, isSelected, cellHasFocus); //To change body of generated methods, choose Tools | Templates.
if (value instanceof Item) {
setText(((Item)value).getText());
}
return this;
}
}
}
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With