I am learning Java and I have to develop an application using a GUI. I have the application working in command line already, but the GUI is driving me insane and costing me in lost hours of head banging and research which is leading nowhere. Can you please help me get the basics working so that i can develop further from there. I want to have a single frame application that can switch between frames on a button click. I created a frame and added three panels P1-P3. These are set as Card Layout (from what i read from forums). Then I added additional panels to these to which i have set colour and buttons.
'''
public class MyMainForm extends JFrame{
private JPanel P1;
private JPanel P2;
private JPanel P3;
private JButton btnFrame1;
private JButton btnFrame2;
private JButton button1;
private JTextField thisIsPanel3TextField;
private JButton btn2Frame1;
private final JFrame frame = new JFrame("MyMain Frame");
public MyMainForm() {
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setContentPane(P1);
pack();
setSize(1000,800);
//setLocation(null);
btnFrame1.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
P1.setVisible(false);
setContentPane(new MyMainForm().P2);
}
});
btnFrame2.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
P2.setVisible(false);
setContentPane(new MyMainForm().P3);
}
});
button1.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
P3.setVisible(false);
setContentPane(new MyMainForm().P2);
}
});
btn2Frame1.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
P1.setVisible(false);
setContentPane(new MyMainForm().P3);
}
});
}
public static void main(String[] args) {
MyMainForm MyMainForm = new MyMainForm();
MyMainForm.setVisible(true);
}
}
'''
I can display P2 or P3 with this new code example above. When i try to go from P2 or P3 back to P1 the content pane doesn't show? Do i need to revalidate the content pane for this to work? I really need to be able to go from P1 to P2
The easiest way to do this is to use a CardLayout. Just follow this example:
JFrame frame = new JFrame();
JPanel p1 = new JPanel();
p1.setBackground(Color.RED);
JPanel p2 = new JPanel();
p2.setBackground(Color.WHITE);
JPanel p3 = new JPanel();
p3.setBackground(Color.BLUE);
//Create the panel that contains the "cards".
JPanel cards = new JPanel(new CardLayout());
cards.add(p1, "Panel 1");
cards.add(p2, "Panel 2");
cards.add(p3, "Panel 3");
// Add your card container to the frame
Container pane = frame.getContentPane();
pane.add(cards, BorderLayout.CENTER);
JButton btn = new JButton("Click me!");
btn.addActionListener(new ActionListener() {
#Override
public void actionPerformed (ActionEvent e) {
CardLayout cl = (CardLayout)(cards.getLayout());
cl.next(cards);
}
});
JPanel btnPanel = new JPanel();
btnPanel.add(btn);
pane.add(btnPanel, BorderLayout.SOUTH);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(400, 400);
frame.setVisible(true);
Alternatively, you can switch to a specific panel by calling cl.show(cards, "Panel X") where X is the number of the panel. This is because the swing argument is the name I assigned to each "card" and the show method recalls panels added to CardLayout by name. For your example, each button should have a listener that uses this method to "show" its assigned panel.
Related
Please help me out to separate these ActionListeners in a periodic table that I am attempting to complete. When I execute the program and click on 'H', it opens all the other elements and when the others are clicked, it does not work. So I need a way to separate these using any method...
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class PeriodicTable
{
public static void main (String[] args)
{
JFrame frame = new JFrame("Elements");
frame.setVisible(true);
frame.setSize(1000,1500);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel panel = new JPanel();
frame.add(panel);
JButton button1 = new JButton("H");
panel.add(button1);
button1.addActionListener (new Action1());
JButton button2 = new JButton("He");
panel.add(button2);
button2.addActionListener (new Action2());
JButton button3 = new JButton("Li");
panel.add(button3);
button3.addActionListener (new Action2());
}
static class Action1 implements ActionListener
{
public void actionPerformed (ActionEvent e)
{
JFrame frame2 = new JFrame("H");
frame2.setVisible(true);
frame2.setSize(1000,1500);
JLabel label = new JLabel("Hydrogen");
JPanel panel = new JPanel();
frame2.add(panel);
panel.add(label);
}
}
static class Action2 implements ActionListener
{
public void actionPerformed (ActionEvent e)
{
JFrame frame3 = new JFrame("He");
frame3.setVisible(true);
frame3.setSize(1000,1500);
JLabel label = new JLabel("Helium");
JPanel panel = new JPanel();
frame3.add(panel);
panel.add(label);
}
}
static class Action3 implements ActionListener
{
public void actionPerformed (ActionEvent e)
{
JFrame frame4 = new JFrame("Li");
frame4.setVisible(true);
frame4.setSize(1000,1500);
JLabel label = new JLabel("Lithium");
JPanel panel = new JPanel();
frame4.add(panel);
panel.add(label);
}
}
}
Thanks in advance.
(note: only the first 3 elements are coded for...)
When I execute the program and click on 'H', it opens all other elements
Only one frame opens for me.
and when the others are clicked, it does not work.
Each button opens a single frame for me.
However, button 3 opens the wrong frame because you add the wrong listener to the button:
//button3.addActionListener (new Action2());
button3.addActionListener (new Action3());
Other issues:
You should add the components to the frame BEFORE making the frame visible.
Don't hardcode screen sizes, you never know what size screen other users will be using
So the order of your code might be something like:
JLabel label = new JLabel("Helium");
JPanel panel = new JPanel();
panel.add(label);
JFrame frame3 = new JFrame("He");
frame3.add(panel);
frame3.pack();
frame3.setVisible(true);
And of course you really don't want to create dozens of separate ActionListeners. You want to make the listener more generic so it can be shared.
Something like:
static class Action implements ActionListener
{
public Action(String element, String description)
{
this.element = element;
this.description = description;
}
public void actionPerformed (ActionEvent e)
{
JLabel label = new JLabel(description);
JPanel panel = new JPanel();
panel.add(label);
JFrame frame3 = new JFrame(element);
frame3.add(panel);
frame3.pack();
frame3.setVisible(true);
}
}
Then when you create the listener you use:
button3.addActionListener (new Action("HE", "Helium"));
My software layout is kinda wizard-base. So the base panel is divided into two JPanels. One left panel which never changes. And one right panel that works with CardLayout. It has many sub-panels and show each one of them by a method.
I can easily go from one inner panel to another one. But I want to have a button in left panel and change panels of the right side.
Here is a sample code which you can run it:
BASE:
public class Base {
JFrame frame = new JFrame("Panel");
BorderLayout bl = new BorderLayout();
public Base(){
frame.setLayout(bl);
frame.setSize(800, 600);
frame.add(new LeftBar(), BorderLayout.WEST);
frame.add(new MainPanel(), BorderLayout.CENTER);
frame.setLocationRelativeTo(null);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
/**
* #param args the command line arguments
*/
public static void main(String[] args) throws IOException {
// TODO code application logic here
new Base();
}
}
Left side
public class LeftBar extends JPanel{
JButton button;
MainPanel mainPanel = new MainPanel();
public LeftBar(){
setPreferredSize(new Dimension(200, 40));
setLayout(new BorderLayout());
setBackground(Color.black);
button = new JButton("Show Second Page");
button.addActionListener(new ActionListener(){
#Override
public void actionPerformed(ActionEvent ae) {
mainPanel.showPanel("secondPage");
}
});
add(button, BorderLayout.NORTH);
}
}
Right Side
public class MainPanel extends JPanel {
private CardLayout cl = new CardLayout();
private JPanel panelHolder = new JPanel(cl);
public MainPanel(){
FirstPage firstPage = new FirstPage(this);
SecondPage secondPage = new SecondPage(this);
setLayout(new GridLayout(0,1));
panelHolder.add(firstPage, "firstPage");
panelHolder.add(secondPage, "secondPage");
cl.show(panelHolder, "firstPage");
add(panelHolder);
}
public void showPanel(String panelIdentifier){
cl.show(panelHolder, panelIdentifier);
}
}
Inner panels for right side:
public class FirstPage extends JPanel {
MainPanel mainPanel;
JButton button;
public FirstPage(MainPanel mainPanel) {
this.mainPanel = mainPanel;
setBackground(Color.GRAY);
button = new JButton("Show page");
button.addActionListener(new ActionListener(){
#Override
public void actionPerformed(ActionEvent ae) {
mainPanel.showPanel("secondPage");
}
});
add(button);
}
}
public class SecondPage extends JPanel{
MainPanel mainPanel;
JButton button;
public SecondPage(MainPanel mainPanel){
this.mainPanel = mainPanel;
setBackground(Color.white);
add(new JLabel("This is second page"));
}
}
And this is a picture to give you the idea:
As I explained, I can travel "from first" page to "second page" by using this method: mainPanel.showPanel("secondPage"); or mainPanel.showPanel("firstPage");.
But I also have a JButton in the left bar, which I call the same method to show the second panel of the CardLayout. But it does not work. It doesnt give any error though.
Any idea how to change these CardLayout panels from outside of panels?
The problem is that LeftBar has mainPanel member that is initialized to a new instance of MainPanel. So you have two instances of MainPanel, one allocated in Base and added to the frame, the other one allocated in LeftBar.
So LeftBar executes mainPanel.showPanel("secondPage"); on a second instance of MainPanel which is not even a part of a visual hierarchy. To fix this just pass an existing instance of MainPanel to the constructor of LeftBar. You already do this in FirstPage and SecondPage.
I have two swing Frames. Frame one will contain a button.when we click the button we will get another frame which will have the five lables(which are the varibles of a class.) with the textfields beside, and a submit button. user will enter the values and clicks submit butoon.
My question is how can retrieve the values from that Frame two when user clicks submit button .i have the code like blelow.
public class Form extends JFrame implements ActionListener {
JPanel panel = new JPanel();
JFrame frame = new JFrame("New frame");
JPanel panel2 = new JPanel();
JButton button = new JButton("add");
JButton button2 = new JButton("Submit");
JLabel label;
JTextField textfield;
public Form() {
setLayout(new BorderLayout());
panel.setLayout(new BoxLayout(panel, BoxLayout.PAGE_AXIS));
panel.setPreferredSize(new Dimension(300, 200));
button.addActionListener(this);
add(panel, BorderLayout.CENTER);
add(button, BorderLayout.SOUTH);
}
public static void main(String[] a) {
Form s = new Form();
s.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
s.pack();
s.setVisible(true);
}
#Override
public void actionPerformed(ActionEvent arg0) {
dispose();
panel2.setLayout(new FlowLayout());
panel2.setPreferredSize(new Dimension(1000, 1000));
final Field[] fields = Employee.class.getFields();
for (Field temp : fields) {
label = new JLabel(temp.getName());
label.setBounds(20, 50, 100, 20);
textfield = new JTextField(20);
textfield.setBounds(140, 50, 100, 20);
panel2.add(label);
panel2.add(textfield);
}
frame.add(panel2);
frame.setSize(290, 300);
frame.setVisible(true);
button2.setSize(20, 30);
frame.add(button2, BorderLayout.SOUTH);
repaint();
revalidate();
button2.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent arg0) {
}
});
}
}
Start by taking a look at The Use of Multiple JFrames, Good/Bad Practice?
Instead of using a second frame, you should use a modal dialog, which, when made visible, will halt your programs execution at that point until it's disposed, at which time it will return and you can extract the values you want from it.
See How to Make Dialogs for more details
Hi all, I was in a development of my college mini project. It was a Library Management system , which i should do in Java swing using Net-beans IDE. First I was doing manual coding. It takes time.
In manual coding I create single JFrame with Menu bar and and items, on all action performed I wrote codes for all Jpanels. It made the file and code huge. and confusing too.
Now I need your help.
I have created a Main JFrame with Menu
A JPanel - ADD Book
another Jpanel - On add book success (demo! , for Actions happening in ADD Book )
I had made action listener
addBook addbk = new addBook();
this.getContentPane().add(addbk);
wrote this code.
I doesn't make sense.
Friends, As a new to java, What i need to study is
1.) How cal and Show an external Jpanel an action performed
2.) How to show another JPanel to same root JFrame if any event has occurred in external JPanel.
In sort, something like Iframe in HTML
Thank you all.
http://compilr.com/abelkbil/openlib/OpenLibMainGUI.java
http://compilr.com/abelkbil/openlib/addBook.java
http://compilr.com/abelkbil/openlib/bookAdded.java
CardLayout, is exactly what you need for this situation. And do learn Java Naming Conventions and stick to them, as you are a beginner, so to be on the right track from the start is always GOOD.
Here is one example, that you can look at :
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class CardLayoutExample
{
private JPanel contentPane;
private MyPanel panel1;
private MyPanel panel2;
private MyPanel panel3;
private JComboBox choiceBox;
private String[] choices = {
"Panel 1",
"Panel 2",
"Panel 3"
};
private void displayGUI()
{
JFrame frame = new JFrame("Card Layout Example");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel contentPane = new JPanel();
contentPane.setBorder(
BorderFactory.createEmptyBorder(5, 5, 5, 5));
contentPane.setLayout(new CardLayout());
choiceBox = new JComboBox(choices);
panel1 = new MyPanel(contentPane
, Color.RED.darker().darker(), this);
panel2 = new MyPanel(contentPane
, Color.GREEN.darker().darker(), this);
panel3 = new MyPanel(contentPane
, Color.DARK_GRAY, this);
contentPane.add(panel1, "Panel 1");
contentPane.add(panel2, "Panel 2");
contentPane.add(panel3, "Panel 3");
frame.getContentPane().add(choiceBox, BorderLayout.PAGE_START);
frame.getContentPane().add(contentPane, BorderLayout.CENTER);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public JComboBox getChoiceBox()
{
return choiceBox;
}
public static void main(String... args)
{
SwingUtilities.invokeLater(new Runnable()
{
public void run()
{
new CardLayoutExample().displayGUI();
}
});
}
}
class MyPanel extends JPanel
{
private JButton jcomp1;
private JPanel contentPane;
private Color backgroundColour;
private JComboBox choiceBox;
public MyPanel(JPanel panel, Color c, CardLayoutExample cle)
{
contentPane = panel;
backgroundColour = c;
choiceBox = cle.getChoiceBox();
setOpaque(true);
setBackground(backgroundColour);
//construct components
jcomp1 = new JButton ("Show New Panel");
jcomp1.addActionListener( new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
String changeToPanel = (String) choiceBox.getSelectedItem();
CardLayout cardLayout = (CardLayout) contentPane.getLayout();
cardLayout.show(contentPane, changeToPanel);
}
});
add(jcomp1);
}
#Override
public Dimension getPreferredSize()
{
return (new Dimension(500, 500));
}
}
Else you can have a look at this example also.
I have a panel on my frame .and by clicking on a button I want to delete the old panel and make the other panel and add that panel to my frame.(also I use netbeans)
would you please help me that how can i do that?thanks
JFrame frame = new JFrame();
final JPanel origPanel = new JPanel();
frame.add(origPanel, BorderLayout.CENTER);
MouseListener ml = new MouseAdapter() {
public void mouseClicked(MouseEvent evt) {
// Mouse clicked on panel so remove existing panel and add a new one.
frame.remove(origPanel);
frame.add(createNewPanel(), BorderLayout.CENTER);
// Revalidate frame to cause it to layout the new panel correctly.
frame.revalidate();
// Stop listening to origPanel (prevent dangling reference).
origPanel.removeMouseListener(this);
}
}
origPanel.addMouseListener(ml);
This way:
final JFrame frame = new JFrame();
frame.setSize(200, 200);
final JPanel panelA = new JPanel();
final JPanel panelB = new JPanel();
JButton button = new JButton("Switch");
button.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
frame.remove(panelA);
frame.add(panelB);
frame.show();
}
});
JLabel label = new JLabel("This is panel B. Panel A is gone!");
panelB.add(label);
panelA.add(button);
frame.add(panelB);
frame.add(panelA);
frame.show();