I have tried to find the answer but I'm coming up short. I am fairly new to java. I have 4 classes (1 main with a JFrame and 3 JPanels).
The main class creates the JFrame and adds the 3 panels to it.
What I am trying to accomplish is update a JLabel or JTextField in 1 panel (panelA) from an ActionEvent in another panel (panelB).
The ActionEvent in panelB runs a method in panelA that runs the setText() method and the repaint() method. I cannot get the JLabel or JTextField to update with the new text.
Here is my code:
App.java
public class App {
public static void main(String[] args) {
JFrame nameFrame = new JFrame("Name Form");
nameFrame.setLayout(new BorderLayout());
nameFrame.setSize(300,150);
nameFrame.setLocationRelativeTo(null);
nameFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
MiddlePanel middlePanel = new MiddlePanel();
nameFrame.add(middlePanel, BorderLayout.CENTER);
BottomPanel bottomPanel = new BottomPanel();
nameFrame.add(bottomPanel, BorderLayout.SOUTH);
nameFrame.setVisible(true);
}
}
BottomPanel.java
import java.awt.FlowLayout;
import javax.swing.JLabel;
import javax.swing.JPanel;
public class BottomPanel extends JPanel {
private JLabel welcomeLabel = new JLabel("Old Text");
BottomPanel() {
super(new FlowLayout());
add(welcomeLabel);
}
public void setText(String text) {
welcomeLabel.setText(text);
repaint();
}
}
MiddlePanel.java
import java.awt.BorderLayout;
import javax.swing.JButton;
import javax.swing.JTextArea;
import javax.swing.JPanel;
import java.awt.event.*;
import java.awt.Graphics;
public class MiddlePanel extends JPanel {
MiddlePanel() {
super(new BorderLayout());
JButton okButton = new JButton("OK");
okButton.setSize(20, 20);
OKButtonListener okButtonListener = new OKButtonListener();
okButton.addActionListener(okButtonListener);
add(okButton, BorderLayout.EAST);
}
class OKButtonListener implements ActionListener {
public void actionPerformed(ActionEvent e) {
BottomPanel bottomPanel = new BottomPanel();
bottomPanel.setText("New Text");
}
}
}
Thanks for any help.
In your OKButtonListener you create a new instance of BottomPanel which has nothing to do with the BottomPanel you added to your JFrame.
You will need the actual reference of the BottomPanel that you added in your JFrame.
d1rk nailed it. Here is one way to achieve that effect.
import java.awt.BorderLayout;
import java.awt.FlowLayout;
import java.awt.event.*;
import javax.swing.*;
public class App {
public static void main(String[] args) {
JFrame nameFrame = new JFrame("Name Form");
nameFrame.setLayout(new BorderLayout());
nameFrame.setSize(300,150);
nameFrame.setLocationRelativeTo(null);
nameFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
BottomPanel bottomPanel = new BottomPanel();
MiddlePanel middlePanel = new MiddlePanel(bottomPanel);
nameFrame.add(middlePanel, BorderLayout.CENTER);
nameFrame.add(bottomPanel, BorderLayout.SOUTH);
nameFrame.setVisible(true);
}
}
class BottomPanel extends JPanel {
private JLabel welcomeLabel = new JLabel("Old Text");
BottomPanel() {
super(new FlowLayout());
add(welcomeLabel);
}
public void setText(String text) {
welcomeLabel.setText(text);
repaint();
}
}
class MiddlePanel extends JPanel {
private BottomPanel bottomPanel;
MiddlePanel(BottomPanel bottomPanel) {
super(new BorderLayout());
this.bottomPanel = bottomPanel;
JButton okButton = new JButton("OK");
okButton.setSize(20, 20);
OKButtonListener okButtonListener = new OKButtonListener();
okButton.addActionListener(okButtonListener);
add(okButton, BorderLayout.EAST);
}
class OKButtonListener implements ActionListener {
public void actionPerformed(ActionEvent e) {
//BottomPanel bottomPanel = new BottomPanel();
bottomPanel.setText("New Text");
}
}
}
Related
I tried to make the first JPanel disappear and the second JPanel visible with the click of a JButton.
So far i only get the first JPanel to show and after clicking the JButton the Frame gets empty.
I also tried to do it with composition so i dont have to extend classes. So my bad understanding of how
composition works might be the problem. I looked into it alot but couldnt find a proper solution for my problem.
First JPanel class:
import java.awt.Color;
import java.awt.Component;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JPanel;
public class Panel1 {
JPanel firstscreenpanel = new JPanel();
JButton jButton1 = new JButton();
Panel1() {
jButton1.setBounds(300,300,400,200);
jButton1.setBackground(Color.BLACK);
jButton1.setVisible(true);
jButton1.addActionListener(new ActionListener() {
Panel2 test = new Panel2();
public void actionPerformed(ActionEvent e) {
firstscreenpanel.setVisible(false);
test.secondscreenpanel.setVisible(true);
}
});
}
public Component panelone() {
firstscreenpanel.setSize(1280, 1024);
firstscreenpanel.setLayout(null);
firstscreenpanel.setBackground(Color.BLUE);
firstscreenpanel.add(jButton1);
firstscreenpanel.setVisible(true);
return firstscreenpanel;
}
}
Second JPanel class:
import java.awt.Color;
import java.awt.Component;
import javax.swing.JButton;
import javax.swing.JPanel;
public class Panel2 {
public JPanel secondscreenpanel = new JPanel();
public JButton jButton2 = new JButton();
Panel2() {
jButton2.setBounds(100,100,400,200);
jButton2.setBackground(Color.BLACK);
jButton2.setVisible(true);
}
public Component paneltwo() {
secondscreenpanel.setSize(1280, 1024);
secondscreenpanel.setLayout(null);
secondscreenpanel.add(jButton2);
secondscreenpanel.setBackground(Color.RED);
secondscreenpanel.setVisible(false);
return secondscreenpanel;
}
}
JFrame Class:
import javax.swing.JFrame;
public class Frame1 {
public JFrame frame1 = new JFrame();
Panel1 panel1 = new Panel1();
Panel2 panel2 = new Panel2();
Frame1() {
frame1.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame1.setState(JFrame.MAXIMIZED_BOTH);
frame1.setSize(1280, 1024);
frame1.setLayout(null);
frame1.add(panel1.panelone());
frame1.add(panel2.paneltwo());
frame1.setVisible(true);
}
}
Main Class:
public class MainClass {
private void showGUI() {
Frame1 jframe = new Frame1();
}
public static void main(String[] args) {
final MainClass main = new MainClass();
javax.swing.SwingUtilities.invokeLater(new Runnable()
{
public void run() {
main.showGUI();
}
});
}
}
I did not check the whole code (too bug, too many empty lines) but stopped at Panel2 test = new Panel2();
is this instance being added to some visible component? if not it will never be displayed.
Note: using a null layout manager is often not recommended, use a CardLayout or even a JTabbedPane to switch components - see tutorial A Visual Guide to Layout Managers
This is not the best implementation, but it is simple enough for you to follow. I modified your code to create a frame containing your original two panels (although those panel classes are not necessary - as I explained in a comment on your posted solution), and a button to toggle visibility on the panels. I am using a regular JButton and not a JToggleButton also not the best use of the class, but simply for you to understand.
The Action Listener is added to the button on the frame. Notice that my action listener does not create new instances of anything. That was part of the original problem. Since the button is a member of the frame class like the panels 1 and 2, it has access to them directly. SO, in the listener, all I need to do is "toggle" the visibility of each of the panels.
public class Frame1 extends JFrame {
private Panel1 panel1 = new Panel1();
private Panel2 panel2 = new Panel2();
private JPanel btnPanel = new JPanel();
private JButton button = new JButton("Toggle");
public Frame1() {
button.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent arg0) {
boolean visible = panel1.isVisible();
panel1.setVisible(!visible);
panel2.setVisible(visible);
}
});
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setState(JFrame.MAXIMIZED_BOTH);
setSize(1280, 1024);
btnPanel.setSize(400, 100);
btnPanel.add(button);
setLayout(null);
add(panel1);
add(panel2);
add(btnPanel);
}
}
public class Panel1 extends JPanel {
public Panel1() {
setBounds(100,100,400,200);
setBackground(Color.RED);
setVisible(true);
}
}
public class Panel2 extends JPanel {
public Panel2() {
setBounds(100,100,400,200);
setBackground(Color.BLACK);
setVisible(false);
}
}
public class MainClass {
private void showGUI() {
Frame1 jframe = new Frame1();
jframe.setVisible(true);
}
public static void main(String[] args) {
final MainClass main = new MainClass();
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
main.showGUI();
}
});
}
}
You can fix your program by passing a reference of your frame to your panel1. See my example below.
Frame class
import javax.swing.*;
public class Frame1 {
private JFrame frame = new JFrame();
private Panel1 panel1;
private Panel2 panel2;
Frame1() {
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setState(JFrame.MAXIMIZED_BOTH);
frame.setSize(1280, 1024);
frame.setLayout(null);
panel1 = new Panel1(this);
frame.add(panel1.getPanel());
panel2 = new Panel2();
frame.add(panel2.getPanel());
frame.setVisible(true);
}
public Panel2 getPanel2() {
return panel2;
}
}
Panel1 class
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
public class Panel1 {
private JPanel panel = new JPanel();
private Frame1 frame1;
private JButton jButton1 = new JButton();
public Panel1(Frame1 frame1) {
this.frame1 = frame1;
panel.setSize(1280, 1024);
panel.setLayout(null);
panel.setBackground(Color.BLUE);
panel.add(jButton1);
panel.setVisible(true);
jButton1.setBounds(300,300,400,200);
jButton1.setBackground(Color.BLACK);
jButton1.setVisible(true);
jButton1.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
panel.setVisible(false);
frame1.getPanel2().getPanel().setVisible(true);
}
});
}
public JPanel getPanel() {
return panel;
}
}
Panel2 class
import javax.swing.*;
import java.awt.*;
public class Panel2 {
private JButton jButton2 = new JButton();
private JPanel panel = new JPanel();
public Panel2() {
panel.setSize(1280, 1024);
panel.setLayout(null);
panel.add(jButton2);
panel.setBackground(Color.RED);
panel.setVisible(false);
jButton2.setBounds(100,100,400,200);
jButton2.setBackground(Color.BLACK);
jButton2.setVisible(true);
}
public JPanel getPanel() {
return panel;
}
}
I solved my problem by adding "public static" to "Panel2 panel2 = new Panel2();"
And then i just used:
"Frame1.panel2.secondscreenpanel.setVisible(true);"
inside the JButton ActionListener.
Its now working but i guess thats a bad way of doing it. Because i heard that using to much static isnt that good. But i dont now why yet.
I'm having trouble with this JApplet. At the moment I have a CardLayout JPanel which contains two BorderLayout JPanels. Whenever I run it, the components added to each 'card' (a JButton to go back to the other JPanel) don't display unless I use setVisible(true) for each LayoutManager. Furthermore, none of my ActionListeners work. I'm assuming because they only use show() and there's something else I have to do that's alluding me.
Must I use setVisible(true)? It seems from other questions that there's a way of doing this without that. Here's the code I'm having trouble with:
/*
*Java Version: 1.8.0_25
*Author: Peadar Ó Duinnín
*Student Number: R00095488
*/
package As1;
import java.awt.BorderLayout;
import java.awt.CardLayout;
import java.awt.Color;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JApplet;
import javax.swing.JButton;
import javax.swing.JLabel;
import javax.swing.JPanel;
public class AUIJApplet extends JApplet implements ActionListener {
private final int WIDTH = 600;
private final int HEIGHT = 400;
private int highScore;
private int currentScore;
JPanel panelCont = new JPanel();
JPanel startPanel = new JPanel();
JPanel gamePanel = new JPanel();
JButton newGameButton = new JButton("New Game");
JButton endGameButton = new JButton("End Game");
JLabel highScoreLabel;
JLabel currentScoreLabel;
CardLayout cl = new CardLayout();
BorderLayout bl = new BorderLayout();
public AUIJApplet() {
highScore = 0;
}
#Override
public void init() {
setSize(WIDTH, HEIGHT);
panelCont.setLayout(cl);
startPanel.setLayout(bl);
gamePanel.setLayout(bl);
startPanel.add(newGameButton, BorderLayout.SOUTH);
gamePanel.add(endGameButton, BorderLayout.SOUTH);
startPanel.setBackground(Color.BLUE);
gamePanel.setBackground(Color.GREEN);
panelCont.add(startPanel, "Start Applet Screen");
panelCont.add(gamePanel, "New Game Screen");
newGameButton.addActionListener((e) -> {
newGame();
});
endGameButton.addActionListener((e) -> {
quitGame();
});
cl.show(panelCont, "Start Applet Screen");
this.add(panelCont);
}
public void newGame() {
cl.show(panelCont, "New Game Screen");
showScores(gamePanel);
}
public void quitGame() {
cl.show(panelCont, "Start Applet Screen");
if (currentScore > highScore) {
highScore = currentScore;
}
currentScore = 0;
}
public void showScores(JPanel currentPanel) {
currentPanel.add(new JLabel("High Score:") , BorderLayout.EAST);
currentPanel.add(highScoreLabel, BorderLayout.EAST);
currentPanel.add(new JLabel("Current Score:"), BorderLayout.EAST);
currentPanel.add(currentScoreLabel, BorderLayout.EAST);
}
#Override
public void actionPerformed(ActionEvent ae) {
}
}
I have made the a little similar code to perform same operation it works for me try to write the code from scratch. Here is my code.
import java.awt.BorderLayout;
import java.awt.CardLayout;
import java.awt.Color;
import java.awt.event.ActionEvent;
import javax.swing.JApplet;
import javax.swing.*;
public class Example extends JApplet {
JPanel panel1,panel2,mainPanel;
JButton start,stop;
CardLayout cl = new CardLayout();
#Override
public void init() {
panel1 = new JPanel();
panel1.setBackground(Color.red);
panel1.setLayout(new BorderLayout());
panel2 = new JPanel();
panel2.setBackground(Color.blue);
panel2.setLayout(new BorderLayout());
start = new JButton("Start");
stop = new JButton("stop");
panel1.add(start,BorderLayout.SOUTH);
panel2.add(stop,BorderLayout.SOUTH);
mainPanel = new JPanel();
mainPanel.setLayout(cl);
mainPanel.add(panel1,"First Panel");
mainPanel.add(panel2, "Second Panel");
start.addActionListener((ActionEvent e) -> {
newGame();
});
stop.addActionListener((ActionEvent e) ->{
endGame();
});
this.add(mainPanel);
}
public void newGame()
{
cl.show(mainPanel, "Second Panel");
}
public void endGame()
{
cl.show(mainPanel,"First Panel");
}
}
Problem - the given codes below is not displaying my JPanel(PageOne) and I am not sure why is it not displaying my JPanel(PageOne). Please Help.
I have added the JPanel(PageOne) to my panel which has a cardLayout();
I have set my JFrame to visible already.
PageOne.java
import javax.swing.JLabel;
import javax.swing.JPanel;
public class PageOne extends JPanel {
public PageOne() {
JLabel label = new JLabel("Page 1");
JPanel panel = new JPanel();
panel.add(label);
} }
PageTwo.java
import javax.swing.JLabel;
import javax.swing.JPanel;
public class PageTwo extends JPanel {
public PageTwo() {
JLabel label = new JLabel("Page 2");
JPanel panel = new JPanel();
panel.add(label);
}
}
DisplayUI.java
import java.awt.CardLayout;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class DisplayUI {
public static void main(String[] args) {
new DisplayUI();
}
public DisplayUI() {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
CardLayout cardLayout = new CardLayout();
JFrame frame = new JFrame("frame");
JPanel panel = new JPanel();
panel.setLayout(cardLayout);
panel.add(new PageOne(), "1");
panel.add(new PageTwo(), "2");
cardLayout.show(panel,"1");
frame.add(panel);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
}
You're not actually adding anything to PageOne or PageTwo panels...
public PageOne() {
JLabel label = new JLabel("Page 1");
JPanel panel = new JPanel();
panel.add(label);
// But nothing is actually added to "this"...
}
Unless you "really" need it, you can get rid of the second JPanel and add the label directly to PageOne (and the same thing goes for PageTwo)
public PageOne() {
JLabel label = new JLabel("Page 1");
add(label);
}
Or add the JPanel you create (which contains the label)
public PageOne() {
JLabel label = new JLabel("Page 1");
JPanel panel = new JPanel();
panel.add(label);
add(panel);
}
Remember, JPanel is type of Container, it can have child components.
Get the content pane of frame and than try adding :
Container container=frame.getContentPane();
container.add(panel);
Hope this helps you.
I want to put JTabbedPane in the middle,and clicking any tab I want to change will reflect in both above and below panel of tabbedpane.
I tried it but it works only on the below panel.
How to overcome from this problem? Please help me.
Thanks in advance.
Here is my code:
jTabbedPane1 = new javax.swing.JTabbedPane();
jTabbedPane1.addTab("Daily Market", jScrollPane1);
jTabbedPane1.addTab("Weekly Market", jScrollPane2);
On assumption that you want to change something in the panels above and below your tabbed pane. Sample code changing text of a label in top and bottom panel below:
import java.awt.BorderLayout;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTabbedPane;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;
public class TestJTabbedPane extends JFrame {
/**
*
*/
private static final long serialVersionUID = 1L;
private void init(){
this.setLayout(new BorderLayout());
JPanel topPanel = new JPanel();
final JLabel topLabel = new JLabel("North");
topPanel.add(topLabel);
this.add(topPanel, BorderLayout.NORTH);
JTabbedPane tabbedPane = new JTabbedPane();
JPanel firstTabCont = new JPanel();
firstTabCont.add(new JLabel("First"));
tabbedPane.addTab("First", firstTabCont);
JPanel secondTabCont = new JPanel();
secondTabCont.add(new JLabel("Second"));
tabbedPane.addTab("Second", secondTabCont);
this.add(tabbedPane, BorderLayout.CENTER);
JPanel bottomPanel = new JPanel();
final JLabel bottomLabel = new JLabel("South");
bottomPanel.add(bottomLabel);
this.add(bottomPanel, BorderLayout.SOUTH);
tabbedPane.addChangeListener(new ChangeListener() {
#Override
public void stateChanged(ChangeEvent evt) {
JTabbedPane pane = (JTabbedPane)evt.getSource();
int selectedIndex = pane.getSelectedIndex();
if(selectedIndex == 0){
topLabel.setText("");
topLabel.setText("Hi");
bottomLabel.setText("");
bottomLabel.setText("Bye");
} else {
topLabel.setText("");
topLabel.setText("Bye");
bottomLabel.setText("");
bottomLabel.setText("Hi");
}
}
});
this.pack();
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.setVisible(true);
}
public static void main(String[] args) {
new TestJTabbedPane().init();
}
}
I want to know how to change the content of a JFrame at runtime. Like adding a new JPanel and removing the old JPanel.
You can consider using CardLayout to change the active panel in a frame.
Changing JPanel at runtime here is the Code :
package stack;
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
public class RemoveAndAddPanel implements ActionListener{
JFrame frame;
JPanel firstPanel;
JPanel secondPanel;
JPanel controlPanel;
JButton nextButton;
JPanel panelContainer;
JButton preButton;
JPanel contentPane;
public RemoveAndAddPanel() {
JFrame.setDefaultLookAndFeelDecorated(true);
frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
firstPanel = new JPanel();
firstPanel.add(new JLabel("FirstPanel"));
firstPanel.setPreferredSize(new Dimension(100,100));
secondPanel = new JPanel();
secondPanel.add(new JLabel("Second panel"));
secondPanel.setPreferredSize(new Dimension(100,100));
panelContainer = new JPanel();
contentPane = new JPanel(new BorderLayout());
nextButton = new JButton("Next panel");
preButton = new JButton("PreButton");
controlPanel = new JPanel();
nextButton.addActionListener(this);
preButton.addActionListener(this);
preButton.setEnabled(false);
controlPanel.add(preButton);
controlPanel.add(nextButton);
panelContainer.setLayout(new BorderLayout());
panelContainer.add(firstPanel,BorderLayout.CENTER);
contentPane.add(controlPanel, BorderLayout.SOUTH);
contentPane.add(panelContainer,BorderLayout.CENTER);
frame.setContentPane(contentPane);
frame.setVisible(true);
frame.setSize(300,100);
}
#Override
public void actionPerformed(ActionEvent e) {
if(e.getSource() == nextButton) {
panelContainer.removeAll();
panelContainer.setSize(0,0);
panelContainer.setSize(secondPanel.getSize());
panelContainer.add(secondPanel,BorderLayout.CENTER);
panelContainer.revalidate();
nextButton.setEnabled(false);
preButton.setEnabled(true);
}
if (e.getSource() == preButton) {
panelContainer.removeAll();
panelContainer.setSize(0,0);
panelContainer.setSize(firstPanel.getSize());
panelContainer.add(firstPanel,BorderLayout.CENTER);
nextButton.setEnabled(true);
preButton.setEnabled(false);
}
}
public static void main(String args[]) {
new RemoveAndAddPanel();
}
}
JFrame.setContentPane()