I'm Using Java Swing. I have kept a Button over a Combo box because for me Coloring button is much easier than Coloring Combo box and I want that when the button is Clicked, all the Combo Box elements should Display. I have kept the combo box and button in Layered Pane and Layout is Absolute Layout.
If it is not possible, how can we change the Background Color of a Combo Box?
Since you didn't provide a minimal runnable example, I went ahead and created this GUI.
Here's the same GUI after I left-clicked the JButton.
As you can see, the JComboBox now has selections.
Oracle has a nifty tutorial, Creating a GUI With Swing, that will teach you how to create a Swing GUI. Skip the Netbeans section.
Here's the complete runnable code.
import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class ComboBoxButton implements Runnable {
public static void main(String[] args) {
SwingUtilities.invokeLater(new ComboBoxButton());
}
private JComboBox<String> comboBox;
#Override
public void run() {
JFrame frame = new JFrame("ComboBox Button");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(createMainPanel(), BorderLayout.CENTER);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
private JPanel createMainPanel() {
JPanel panel = new JPanel(new BorderLayout());
panel.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
JButton button = new JButton("Click Me");
button.addActionListener(new ButtonListener());
panel.add(button, BorderLayout.BEFORE_FIRST_LINE);
comboBox = new JComboBox<>();
panel.add(comboBox, BorderLayout.CENTER);
return panel;
}
public class ButtonListener implements ActionListener {
private boolean firstTimeSwitch = true;
#Override
public void actionPerformed(ActionEvent event) {
if (firstTimeSwitch) {
String[] selection = { "alpha", "beta", "gamma", "zeta" };
for (int index = 0; index < selection.length; index++) {
comboBox.addItem(selection[index]);
}
firstTimeSwitch = false;
}
}
}
}
Related
I'm trying to add a JComponent onto a Jpanel whenever I switch my selection for daysOfTheWeek comboBox. However, it doesn't seem to work, but only works when I put it ouside of theactionPerformed(ActionEvent e) method. What am I doing wrong? Here is my simplified code:
public class App extends JFrame {
public static final int WIDTH = 1900;
public static final int HEIGHT = 1000;
JPanel scheduleArea;
private String[] days = {"Monday", "Tuesday"};
public App() {
super("Schedule");
scheduleArea = new JPanel();
initializeGraphics();
}
public void initializeGraphics() {
setMinimumSize(new Dimension(WIDTH, HEIGHT));
getContentPane().setBackground(Color.LIGHT_GRAY);
getContentPane().setLayout(null);
createScheduleArea();
setVisible(true);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
public void createScheduleArea() {
JPanel schedulePanel = new JPanel();
schedulePanel.setBounds(850,40,990,870);
schedulePanel.setLayout(null);
scheduleArea.setBounds(25,105,940,740);
scheduleArea.setBackground(new java.awt.Color(197,218,221));
JComboBox daysOfTheWeek = new JComboBox(days);
daysOfTheWeek.setBounds(750,30,200,45);
schedulePanel.add(daysOfTheWeek);
daysOfTheWeek.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
String selectedDay = (String) daysOfTheWeek.getSelectedItem();
switch (selectedDay) {
case "Monday":
scheduleArea.add(new JLabel("Monday")); // JLabel not added
break;
case "Tuesday":
scheduleArea.add(new JLabel("Tuesday"));
break;
default:
System.out.println("Please select");
}
}
});
schedulePanel.add(scheduleArea);
add(schedulePanel);
}
}
Oracle has a helpful tutorial, Creating a GUI With Swing. Skip the Learning Swing with the NetBeans IDE section. Pay close attention to the Laying Out Components Within a Container section.
Generally, you design a Swing GUI so that you create all the Swing components once. Then, you update the values of the Swing Components.
Generally, you create a Swing GUI from the inside out. You define your Swing components and JPanels and let the JFrame size itself.
Here's a GUI I came up with, based on your GUI.
I use a JFrame. The only time you should extend a JFrame, or any Java class, is when you want to override one or more of the class methods.
I created two separate JPanels, one for the JComboBox and one for the JTextArea. I added a JButton to the combo box panel so you could select the same day more than once. I used a JTextArea so I could define one Swing component and append the text.
Here's the complete runnable code.
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.SwingUtilities;
public class SchedulingApplication implements Runnable {
public static void main(String[] args) {
SwingUtilities.invokeLater(new SchedulingApplication());
}
private JTextArea textArea;
#Override
public void run() {
JFrame frame = new JFrame("Schedule");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(createComboBoxPanel(), BorderLayout.NORTH);
frame.add(createSchedulePanel(), BorderLayout.CENTER);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
private JPanel createComboBoxPanel() {
JPanel panel = new JPanel(new FlowLayout(FlowLayout.TRAILING, 5, 5));
panel.setBorder(BorderFactory.createEmptyBorder(0, 5, 5, 5));
String[] days = { "Monday", "Tuesday" };
JComboBox<String> daysOfTheWeek = new JComboBox<>(days);
panel.add(daysOfTheWeek);
JButton button = new JButton("Select");
button.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
String selectedDay = (String) daysOfTheWeek.getSelectedItem();
switch (selectedDay) {
case "Monday":
case "Tuesday":
textArea.append(selectedDay);
textArea.append(System.lineSeparator());
break;
default:
System.out.println("Please select");
}
}
});
panel.add(button);
return panel;
}
private JPanel createSchedulePanel() {
JPanel panel = new JPanel(new BorderLayout());
panel.setBorder(BorderFactory.createEmptyBorder(0, 5, 5, 5));
textArea = new JTextArea(10, 40);
textArea.setBackground(new Color(197, 218, 221));
JScrollPane scrollPane = new JScrollPane(textArea);
panel.add(scrollPane);
return panel;
}
}
This is a java template i found about Card Layout
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class Main {
private static final String CARD_JBUTTON = "Card JButton";
private static final String CARD_JTEXTFIELD = "Card JTextField";
private static final String CARD_JRADIOBUTTON = "Card JRadioButton";
private static void createAndShowGUI()
{
JFrame frame = new JFrame("Card Layout Test");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLocationRelativeTo(null);
// This JPanel is the base for CardLayout for other JPanels.
final JPanel contentPane = new JPanel();
contentPane.setLayout(new CardLayout(200, 200));
/* Here we be making objects of the Window Series classes
* so that, each one of them can be added to the JPanel
* having CardLayout.
*/
Window1 win1 = new Window1();
contentPane.add(win1, CARD_JBUTTON);
Window2 win2 = new Window2();
contentPane.add(win2, CARD_JTEXTFIELD);
Window3 win3 = new Window3();
contentPane.add(win3, CARD_JRADIOBUTTON);
/* We need two JButtons to go to the next Card
* or come back to the previous Card, as and when
* desired by the User.
*/
JPanel buttonPanel = new JPanel();
final JButton previousButton = new JButton("PREVIOUS");
previousButton.setBackground(Color.BLACK);
previousButton.setForeground(Color.WHITE);
final JButton nextButton = new JButton("NEXT");
nextButton.setBackground(Color.RED);
nextButton.setForeground(Color.WHITE);
buttonPanel.add(previousButton);
buttonPanel.add(nextButton);
/* Adding the ActionListeners to the JButton,
* so that the user can see the next Card or
* come back to the previous Card, as desired.
*/
previousButton.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent ae)
{
CardLayout cardLayout = (CardLayout) contentPane.getLayout();
cardLayout.previous(contentPane);
}
});
nextButton.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent ae)
{
CardLayout cardLayout = (CardLayout) contentPane.getLayout();
cardLayout.next(contentPane);
}
});
// Adding the contentPane (JPanel) and buttonPanel to JFrame.
frame.add(contentPane, BorderLayout.CENTER);
frame.add(buttonPanel, BorderLayout.PAGE_END);
frame.pack();
frame.setVisible(true);
}
public static void main(String... args)
{
SwingUtilities.invokeLater(new Runnable()
{
public void run()
{
createAndShowGUI();
}
});
}
And this is my Window1.java
import java.awt.Color;
import java.awt.FlowLayout;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JTextField;
class Window1 extends JPanel
{
/*
* Here this is our first Card of CardLayout, which will
* be added to the contentPane object of JPanel, which
* has the LayoutManager set to CardLayout.
* This card consists of Two JButtons.
*/
private ActionListener action;
public Window1()
{
init();
}
private void init()
{
final JButton clickButton = new JButton("Click ME");
final JButton dontClickButton = new JButton("DON\'T CLICK ME");
final JTextField title = new JTextField(12);
action = new ActionListener()
{
public void actionPerformed(ActionEvent ae)
{
if (ae.getSource() == clickButton)
{
String myString = title.getText();
System.out.println(myString);
}
else if (ae.getSource() == dontClickButton)
{
JOptionPane.showMessageDialog(null, "I told you not to click me!"
, "Wrong Button", JOptionPane.PLAIN_MESSAGE);
}
}
};
clickButton.addActionListener(action);
dontClickButton.addActionListener(action);
add(clickButton);
add(dontClickButton);
add(title);
}
}
Now my problem is that how do i set the position of the textfields and buttons in Window1?
With this code they are set in the center of the view aligned horizontally.
I tried to use title.setLocation(5,5); but it's not working. Any suggestions?
Now my problem is that how do i set the position of the textfields and buttons in Window1?
Rows like Jlabel - JTextField then new row ,and in the end of the page the button
The thing is you're not using any layout managers. The default layout manager for JPanel is FlowLayout, which will do exactly what you're experiencing (horizontal layout of the components).
Getting vertical alignment could be achieved by using different layout managers. You could use a GridBagLayout for all the component, or a GridLayout, or you could nest JPanel with different layout managers. The possibilities are endless. It just comes down to the exact look you want.
See Laying out Components Within a Container to learn how to use different layout managers. I'll give you an example, but don't let it stop you from looking at the tutorials. You need to learn them.
Also besides just positioning of the components layout managers use dynamic sizing either by respecting the preferred of components are not respecting them. You can see a picture in this answer of some of the layout managers that do and don't respect preferred sizes.
import java.awt.FlowLayout;
import java.awt.GridBagLayout;
import java.awt.GridLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JRadioButton;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;
public class LayoutManagers extends JPanel{
public LayoutManagers() {
JLabel label = new JLabel("Text Field");
JTextField textField = new JTextField(20);
JRadioButton rb1 = new JRadioButton("Radio 1");
JRadioButton rb2 = new JRadioButton("Radio 2");
JButton button = new JButton("Button");
JPanel panel1 = new JPanel();
panel1.add(label);
panel1.add(textField);
JPanel panel2 = new JPanel();
panel2.add(rb1);
panel2.add(rb2);
JPanel panel3 = new JPanel(new FlowLayout(FlowLayout.TRAILING));
panel3.add(button);
JPanel panel4 = new JPanel(new GridLayout(3, 1));
panel4.add(panel1);
panel4.add(panel2);
panel4.add(panel3);
setLayout(new GridBagLayout());
add(panel4);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable(){
public void run() {
JFrame frame = new JFrame();
frame.add(new LayoutManagers());
frame.pack();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
});
}
}
I have a MainPanel which uses the Gridlayout. Consequently I have created four JPanel classes for the: NORTH, EAST, CENTER and EAST layouts respectively. I then add all four to my MainPanel.
However, on my WEST panel I use another grid layout to store JButtons and JTextFields. I want to constantly update my JTextFields as they display a value (that changes when a button on another panel is clicked). How do I allow that value to be changed when the JFrame is running?
I tried using paintComponent, but it keeps on adding multiple copies of the same JTextField after each other, as I add it in my paintComponent method. If I remove the add method the values won't update.
Action works well to encapsulate such functionality. In the example below, a number of text fields listen for an ActionEvent received from a single Update button. The common UpdateHandler is derived from AbstractAction.
import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Date;
import javax.swing.AbstractAction;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;
/** #see http://stackoverflow.com/a/14947144/230513 */
public class Test {
private JButton button = new JButton("Update");
private void display() {
JFrame f = new JFrame("Test");
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.add(createPanel(button), BorderLayout.NORTH);
f.add(createPanel(button), BorderLayout.WEST);
f.add(createPanel(button), BorderLayout.EAST);
f.add(createPanel(button), BorderLayout.SOUTH);
JPanel p = new JPanel();
p.add(button);
f.add(p, BorderLayout.CENTER);
f.getRootPane().setDefaultButton(button);
f.pack();
f.setLocationRelativeTo(null);
f.setVisible(true);
}
private static JPanel createPanel(JButton b) {
JPanel panel = new JPanel(new FlowLayout(FlowLayout.CENTER));
final JTextField text = new JTextField();
b.addActionListener(new UpdateHandler(text));
panel.add(text);
return panel;
}
private static class UpdateHandler extends AbstractAction {
private JTextField text;
private DateFormat df = new SimpleDateFormat("HH:mm:ss.SSS");
public UpdateHandler(JTextField t) {
super("update");
t.setText(df.format(new Date()));
this.text = t;
}
#Override
public void actionPerformed(ActionEvent e) {
text.setText(df.format(new Date()));
}
}
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
new Test().display();
}
});
}
}
I designed an interface for the welcome screen with one JFrame included two JPanels (JPanel1 on right and JPanel2 on left). The buttons on the left is to switch the Panels in JPanel1. I want to press on a button to replace JPanel1 content with another JPanel but I don`t know how. Please help.
Here is a very simple example of something that should approximate your description. On the left, we have a hug button to toggle the content of the right panel. On the right, you have a panel with a given border and a label. When you press the button, the content on the right is swapped with the other panel.
import java.awt.BorderLayout;
import java.awt.CardLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class TestCardLayout2 {
protected void initUI() {
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel leftPanel = new JPanel(new BorderLayout());
JLabel label = new JLabel("Left panel");
leftPanel.add(label, BorderLayout.NORTH);
JButton button = new JButton("Toggle right panel");
leftPanel.add(button);
frame.add(leftPanel, BorderLayout.WEST);
final CardLayout cardLayout = new CardLayout();
final JPanel rightPanel = new JPanel(cardLayout);
rightPanel.setPreferredSize(new Dimension(200, 500));
JPanel rightPanel1 = new JPanel(new FlowLayout(FlowLayout.LEFT));
rightPanel1.setBorder(BorderFactory.createLineBorder(Color.RED));
JPanel rightPanel2 = new JPanel(new FlowLayout(FlowLayout.RIGHT));
rightPanel2.setBorder(BorderFactory.createLineBorder(Color.BLUE));
JLabel label1 = new JLabel("Right panel 1 with a red border");
JLabel label2 = new JLabel("Right panel 2 with a blue borer");
rightPanel1.add(label1);
rightPanel2.add(label2);
rightPanel.add(rightPanel1, "panel1");
rightPanel.add(rightPanel2, "panel2");
frame.add(rightPanel, BorderLayout.EAST);
button.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
cardLayout.next(rightPanel);
}
});
frame.pack();
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
new TestCardLayout2().initUI();
}
});
}
}
An alternative to CardLayout would be JRootPane and its JRootPane.setContentPane() method. Here's an example:
final JPanel panel1 = ...;
final JPanel panel2 = ...;
boolean showingPanel1 = true;
final JRootPane rootPane = new JRootPane();
rootPane.setContentPane(panel1);
JButton switchButton = new JButton("Switch");
switchButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent evt) {
if (showingPanel1) {
rootPane.setContentPane(panel2);
} else {
rootPane.setContentPane(panel1);
}
showingPanel = !showingPanel;
}
});
Add the rootPane and switchButton components to your window, and then clicking switchButton will switch out the panels.
Here's a tutorial. You should mostly be concerned with JRootPane.setContentPane, the other stuff in the tutorial isn't relevant.
The best answer I found is that I will create one JFrame only and gonna make one big JPanel include two JPanels (JPanelLeft include the buttons and JPanelRight include what the button do) then I will copy the main JPanel for each JButton.
When I press on any button I will do (JFrame.getContentPane.removeAll) to remove the old JPanel then (JFrame.getContentPane.Add(NewJPanel).
This works for me and keep my design as I Want. Thanks for every body.
I have a JComboBox with a list of elements. So what the program basically does is user select an element from the combo list and click a button to display the selected element in the text area.
Everything works perfect so far, but the problem is after user click the button I want the combo box to return back to the firs element and display the first element. How can I display the first element of the combo box...????
Try JComboBox#setSelectedIndex(0).
In the action listener you have to reset the selectedIndex of the comboBox to the first position after you have updated the text area with the selected value.
Sample code :
package com.mumz.test.swing;
import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextArea;
import javax.swing.border.Border;
public class JComboBoxTest {
private void init(){
JPanel panel = new JPanel(new BorderLayout());
Object[] values = new String[]{"One","Two","Three"};
final JComboBox comboBox = new JComboBox(values);
panel.add(comboBox, BorderLayout.NORTH);
final JTextArea textArea = new JTextArea(2, 2);
panel.add(textArea, BorderLayout.CENTER);
JButton button = new JButton("Action");
button.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
textArea.setText((String) comboBox.getSelectedItem()) ;
comboBox.setSelectedIndex(0);
}
});
panel.add(button, BorderLayout.SOUTH);
JFrame frame = new JFrame();
frame.add(panel);
frame.pack();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
public static void main(String[] args) {
new JComboBoxTest().init();
}
}
JComboBox implements two methods for set Item
comboBox.setSelectedIndex(int);
comboBox.setSelectedItem(Object);
more in the example