How to add JPanel to JFrame in other class?? I've tried with this code, but when I compile it, it didn't show any component in MyFrame.java (the label "Hello World"). What's wrong with my code?
(Button in MainFrame.java called the MyFrame.java)
Here's the code:
MyPanel.java (contains button and label)
public class MyPanel extends javax.swing.JPanel {
public MyPanel() {
initComponents();
myLabel.setText("Hello World");
}
}
MyFrame.java
public class MyFrame extends javax.swing.JFrame {
MyPanel myPanel = new MyPanel();
public MyFrame() {
initComponents();
this.add(myPanel);
}
}
MainFrame.java
public class MainFrame extends javax.swing.JFrame {
public MainFrame() {
initComponents();
}
private void btnCallFrameActionPerformed(java.awt.event.ActionEvent evt) {
new MyFrame().setVisible(true);
}
public static void main(String args[]) {
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new MainFrame().setVisible(true);
}
});
}
}
I don't know what you have done in initComponents method. So I have changed your code a little bit.
public class MyPanel extends javax.swing.JPanel {
public MyPanel() {
initComponents();
//I don't know what you did in initComponents(); so I ve changed the layout to be sure that you didn't use null layout.
this.setLayout(new BorderLayout());
JLabel myLabel = new JLabel();
myLabel.setText("Hello World");
//adding the label in MyPanel
this.add(myLabel);
}
}
public class MyFrame extends javax.swing.JFrame {
MyPanel myPanel = new MyPanel();
public MyFrame() {
initComponents();
// added because of the former reason
this.setLayout(new BorderLayout());
this.add(myPanel);
}
}
I hope you are sure that you can call the btnCallFrameActionPerformed method with some button.
Related
I'm working on a very complicated, multi-layered Swing GUI, and the main issue I'm running into right now involves having a JButton ActionListener perform setVisible() on a separate JFrame and immediately dispose() of the current JFrame. Because of the length of my code, it's important that main, both JFrames, and the ActionListener are all split into individual class files. I wrote a VERY simplified version of my problem, split into 4 tiny class files. Here they are:
File 1:
import javax.swing.*;
public class Test {
public static void main(String[] args) {
JFrame g1 = new GUI1();
g1.pack();
g1.setLocation(200,200);
g1.setVisible(true);
JFrame g2 = new GUI2();
g2.pack();
g2.setLocation(400,200);
g2.setVisible(false);
}
}
File 2:
import javax.swing.*;
public class GUI1 extends JFrame {
JPanel panel;
JButton button;
public GUI1() {
super("GUI1");
setDefaultCloseOperation(EXIT_ON_CLOSE);
panel = new JPanel();
button = new JButton("Create GUI2");
button.addActionListener(new Listener());
add(panel);
add(button);
}
}
File 3:
import javax.swing.*;
public class GUI2 extends JFrame {
JPanel panel;
JLabel label;
public GUI2() {
super("GUI2");
setDefaultCloseOperation(EXIT_ON_CLOSE);
panel = new JPanel();
label = new JLabel("I'm alive!");
add(panel);
add(label);
}
}
File 4:
import java.awt.event.*;
public class Listener implements ActionListener {
public void actionPerformed(ActionEvent e) {
GUI2.setVisible(true);
GUI1.dispose();
}
}
As you can see, the only function of the ActionListener is to set GUI2 to visible and dispose of GUI1, but it runs the error "non-static method (setVisible(boolean) and dispose()) cannot be referenced from a static context". I figure this is because both methods are trying to reference objects that were created in main, which is static. My confusion is how to get around this, WITHOUT combining everything into one class.
Any suggestions? Thanks!
EDIT:
Here's the above code compiled into one file... although it returns the exact same error.
import javax.swing.*;
import java.awt.event.*;
public class Test {
public static void main(String[] args) {
JFrame g1 = new GUI1();
g1.pack();
g1.setLocation(200,200);
g1.setVisible(true);
JFrame g2 = new GUI2();
g2.pack();
g2.setLocation(400,200);
g2.setVisible(false);
}
}
class GUI1 extends JFrame {
JPanel panel;
JButton button;
public GUI1() {
super("GUI1");
setDefaultCloseOperation(EXIT_ON_CLOSE);
panel = new JPanel();
button = new JButton("Create GUI2");
button.addActionListener(new Listener());
add(panel);
add(button);
}
}
class GUI2 extends JFrame {
JPanel panel;
JLabel label;
public GUI2() {
super("GUI2");
setDefaultCloseOperation(EXIT_ON_CLOSE);
panel = new JPanel();
label = new JLabel("I'm alive!");
add(panel);
add(label);
}
}
class Listener implements ActionListener {
public void actionPerformed(ActionEvent e) {
GUI2.setVisible(true);
GUI1.dispose();
}
}
You have to pass instances of frame1 and frame2 to your ActionListener.
import java.awt.event.*;
public class Listener implements ActionListener {
private JFrame frame1, frame2;
public Listener(JFrame frame1, JFrame frame2) {
this.frame1 = frame1;
this.frame2 = frame2;
}
public void actionPerformed(ActionEvent e) {
frame2.setVisible(true);
frame1.dispose();
}
}
This means you have to pass an instance of frame2 to your GUI1 class.
import javax.swing.*;
public class GUI1 extends JFrame {
JPanel panel;
JButton button;
public GUI1(JFrame frame2) {
super("GUI1");
setDefaultCloseOperation(EXIT_ON_CLOSE);
panel = new JPanel();
button = new JButton("Create GUI2");
button.addActionListener(new Listener(this, frame2));
add(panel);
add(button);
}
}
This means you have to create the frames in the reverse order.
import javax.swing.*;
public class Test {
public static void main(String[] args) {
JFrame g2 = new GUI2();
g2.pack();
g2.setLocation(400,200);
g2.setVisible(false);
JFrame g1 = new GUI1(g2);
g1.pack();
g1.setLocation(200,200);
g1.setVisible(true);
}
}
I am new(ish) to Java Swing but I have not been able to find an elegant solution to my issue so I thought I'd raise a question here.
I am trying to make my current JPanel change to another JPanel based on a button click event from within the current JPanel. In essence just hiding one panel and displaying the other. I feel this can be done within my MainFrame class however I'm not sure how to communicate this back to it. Nothing I am trying simply seems to do as desired, I'd appreciate any support. Thanks
App.java
public static void main(final String[] args) {
MainFrame mf = new MainFrame();
}
MainFrame.java
public class MainFrame extends JFrame {
public MainFrame(){
setTitle("Swing Application");
setSize(1200, 800);
setDefaultCloseOperation(DISPOSE_ON_CLOSE);
setVisible(true);
// First Page Frame switch
getContentPane().add(new FirstPage());
}
}
FirstPage.java
public class FirstPage extends JPanel {
public FirstPage() {
setVisible(true);
JButton clickBtn = new JButton("Click");
clickBtn.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent actionEvent) {
// Change to SecondPage JPanel here.
}
});
add(clickBtn);
}
}
SecondPage.java
public class SecondPage extends JPanel {
public SecondPage() {
setVisible(true);
add(new JLabel("Welcome to the Second Page"));
}
}
Any more information needed, please ask thanks :)
I think the best way is to use CardLayout. It is created for such cases. Check my example:
public class MainFrame extends JFrame {
private CardLayout cardLayout;
public MainFrame() {
super("frame");
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
cardLayout = new CardLayout();
getContentPane().setLayout(cardLayout);
getContentPane().add(new FirstPage(this::showPage), Pages.FIRST_PAGE);
getContentPane().add(new SecondPage(this::showPage), Pages.SECOND_PAGE);
setLocationByPlatform(true);
pack();
}
public void showPage(String pageName) {
cardLayout.show(getContentPane(), pageName);
}
public static interface PageContainer {
void showPage(String pageName);
}
public static interface Pages {
String FIRST_PAGE = "first_page";
String SECOND_PAGE = "second_page";
}
public static class FirstPage extends JPanel {
public FirstPage(PageContainer pageContainer) {
super(new FlowLayout());
JButton button = new JButton("next Page");
button.addActionListener(e -> pageContainer.showPage(Pages.SECOND_PAGE));
add(button);
}
}
public static class SecondPage extends JPanel {
public SecondPage(PageContainer pageContainer) {
super(new FlowLayout());
add(new JLabel("This is second page."));
JButton button = new JButton("Go to first page");
button.addActionListener(e -> pageContainer.showPage(Pages.FIRST_PAGE));
add(button);
}
}
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> new MainFrame().setVisible(true));
}
}
CardLayout is the right tool for the job.
You can simply create the ActionListener used to swap pages in JFrame class, and pass a reference of it to FirstPage:
import java.awt.CardLayout;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
public class MainFrame extends JFrame {
public MainFrame(){
setTitle("Swing Application");
setSize(1200, 800);
setDefaultCloseOperation(DISPOSE_ON_CLOSE);
setLocationByPlatform(true);
//Create card layout and set it to the content pane
CardLayout cLayout = new CardLayout();
setLayout(cLayout);
//create and add second page to the content pane
JPanel secondPage = new SecondPage();
add("SECOND",secondPage);
//create an action listener to swap pages
ActionListener listener = actionEvent ->{
cLayout.show(getContentPane(), "SECOND");
};
//use the action listener in FirstPage
JPanel firstPage = new FirstPage(listener);
add("FIRST", firstPage);
cLayout.show(getContentPane(), "FIRST");
setVisible(true);
}
public static void main(String[] args) {
new MainFrame();
}
}
class FirstPage extends JPanel {
public FirstPage(ActionListener listener) {
JButton clickBtn = new JButton("Click");
clickBtn.addActionListener(listener);
add(clickBtn);
}
}
class SecondPage extends JPanel {
public SecondPage() {
add(new JLabel("Welcome to the Second Page"));
}
}
Hi, I'm new to Java and I have the following problem:
I created a JFrame and I want the JPanel to change when clicking a JButton. That does almost work.The only problem is that the program creates a new window and then there are two windows. One with the first JPanel and one with the second JPanel.
Here is my current code:
first class:
public class Program {
public static void main (String [] args) {
new window(new panel1());
}
}
second class:
import java.awt.Toolkit;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class Window extends JFrame {
private static final long serialVersionUID = 1L;
Window(JPanel panel) {
setLocation((int) Toolkit.getDefaultToolkit().getScreenSize().getWidth() / 2 - 200,
(int) Toolkit.getDefaultToolkit().getScreenSize().getHeight() / 2 - 100);
setSize(400, 200);
setTitle("test");
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setResizable(false);
setContentPane(panel);
setVisible(true);
}
}
third class:
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JPanel;
public class Panel1 extends JPanel {
private final long serialVersionUID = 1L;
Panel1() {
JButton nextPanelButton = new JButton("click here");
add(nextPanelButton);
ActionListener changePanel = new ActionListener() {
#Override
public void actionPerformed(ActionEvent event) {
new window(new panel2());
}
};
nextPanelButton.addActionListener(changePanel);
}
}
fourth class:
public class Panel2 extends JPanel {
private static final long serialVersionUID = 1L;
Panel2() {
JLabel text = new JLabel("You pressed the Button!");
add(text);
}
}
But I just want to change the JPanel without opening a new window. Is there a way to do that?
Thanks in advance!
This is a demo
import javax.swing.*;
public class Main {
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> {
new MainFrame("Title").setVisible(true);
});
}
}
MainFrame.java
import javax.swing.*;
import java.awt.*;
public class MainFrame extends JFrame {
private JPanel viewPanel;
public MainFrame(String title) {
super(title);
createGUI();
}
private void createGUI() {
setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
setLayout(new BorderLayout());
setMinimumSize(new Dimension(600, 480));
viewPanel = new JPanel(new BorderLayout());
add(viewPanel, BorderLayout.CENTER);
showView(new View1(this));
pack();
}
public void showView(JPanel panel) {
viewPanel.removeAll();
viewPanel.add(panel, BorderLayout.CENTER);
viewPanel.revalidate();
viewPanel.repaint();
}
}
View1.java
import javax.swing.*;
import java.awt.*;
public class View1 extends JPanel {
final private MainFrame owner;
public View1(MainFrame owner) {
super();
this.owner = owner;
createGUI();
}
private void createGUI() {
setLayout(new FlowLayout());
add(new JLabel("View 1"));
JButton button = new JButton("Show View 2");
button.addActionListener(event -> {
SwingUtilities.invokeLater(() -> owner.showView(new View2(owner)));
});
add(button);
}
}
View2.java
import javax.swing.*;
import java.awt.*;
public class View2 extends JPanel {
final private MainFrame owner;
public View2(MainFrame owner) {
super();
this.owner = owner;
createGUI();
}
private void createGUI() {
setLayout(new FlowLayout());
add(new JLabel("View 2"));
JButton button = new JButton("Show View 1");
button.addActionListener(event -> {
SwingUtilities.invokeLater(() -> owner.showView(new View1(owner)));
});
add(button);
}
}
First of all, take a look at Java naming conventions, in particular your class names should start with a capitalized letter.
If you want to avoid to open a new window every time you click the button, you could pass your frame object to Panel1 constructor, and setting a new Panel2 instance as the frame content pane when you click the button. There is also no need to pass Panel1 to Window constructor (please note that Window class is already defined in java.awt package, it would be better to avoid a possible name clash renaming your class ApplicationWindow, MyWindow or something else).
You could change your code like this (only relevant parts):
public class Program
{
public static void main (String [] args) {
SwingUtilities.invokeLater (new Runnable () {
#Override public void run () {
new Window ().setVisible (true);
}
};
}
}
class Window extends JFrame
{
// ...
Window () {
// ...
setContentPane(new Panel1 (this));
}
}
class Panel1 extends JPanel
{
// ...
Panel1 (JFrame parent) {
// ...
ActionListener changePanel = new ActionListener() {
#Override
public void actionPerformed(ActionEvent event) {
parent.setContentPane (new Panel2 ());
}
};
// ...
}
Also note the SwingUtilities's invokeLater call, which is the best way to initialise your GUI in the EDT context (for more info look at this question).
Finally, you could avoid to create a new Panel2 instance every time you click the button, simply by using a CardLayout.
Take a look at the official tutorial.
This is an old post, but it may be useful to answer it in a simplified way. Thanks to mr mcwolf for the first answer.
If we want to make 1 child jframe interact with a main jframe in order to modify its content, let's consider the following case.
parent.java and child.java.
So, in parent.java, we have something like this:
Parent.java
public class Parent extends JFrame implements ActionListener{
//attributes
//here is the class we want to modify
private some_class_to_modify = new some_class_to_modify();
//here is a container which contains the class to modify
private JPanel container = new JPanel();
private some_class = new some_class();
private int select;
//....etc..etc
//constructor
public Parent(){
this.setTitle("My title");
//etc etc
//etc....etc
container.add(some_class_to_modify,borderLayout.CENTER);
}
//I use for instance actionlisteners on buttons to trigger the new JFrame
public void actionPerformed(ActionEvent arg0){
if((arg0.getSource() == source_button_here)){
//Here we call the child class and send the parent's attributes with "this"
Child child = new Child(this);
}
//... all other cases
}//Here is the class where we want to be able to modify our JFrame. Here ist a JPanel (Setcolor)
public void child_action_on_parent(int selection){
this.select = selection;
System.out.println("Selection is: "+cir_select);
if(select == 0) {
//Do $omething with our class to modify
some_class_to_modify.setcolor(Color.yellow);
}
}
In child.java we would have something like this:
public class Child extends JFrame implements ActionListener {
//Again some attributes here
private blabla;
//Import Parent JFrame class
private Parent owner;
private int select_obj=0;
//Constructor here and via Parent Object Import
public Child(Parent owner){
/*By calling the super() method in the constructor method, we call the parent's
constructor method and gets access to the parent's properties and methods:*/
super();
this.owner = owner;
this.setTitle("Select Method");
this.setSize(400, 400);
this.setContentPane(container);
this.setVisible(true);
}
class OK_Button implements ActionListener {
public void actionPerformed(ActionEvent e) {
Object Selection = select;
if(Selection == something) {
select_obj=0;
valid = JOptionPane.showConfirmDialog(null,"You have chosen option 1. Do you want to continue?","Minimum diameter",2);
}
System.out.println("Option is:"+valid);
if(valid == 0) {
setVisible(false);
//Here we can use our herited object to call the child_action_on_parent public class of the Parent JFrame. So it can modify directly the Panel
owner.child_action_on_parent(select_obj);
}
}
}
I've got class 'Frame' which extends JFrame and separetad JPanels: MainMenu and SinglePanel
I am using CardLayout, but I've got problem when switching back to panels using buttonSingle and powrot buttons. So my question is how can I change/swap between cards using these buttons?
My Frame class:
public class Frame extends JFrame{
CardLayout cl = new CardLayout();
final MainMenu menuPanel = new MainMenu();
final SinglePanel singlePanel = new SinglePanel();
public Frame(){
setLayout(cl);
add(menuPanel,"menu");
add(singlePanel,"single");
setSize(200, 200);
setLocationRelativeTo(null);
setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
setVisible(true);
setEnabled(true);
swapView("menu");
}
public void swapView(String view){
cl.show(getContentPane(),view);
}
}
my MainMenu class:
public class MainMenu extends JPanel{
public MainMenu(){
setLayout(new BoxLayout(this , BoxLayout.Y_AXIS));
add(Box.createVerticalGlue());
JButton buttonSingle = new JButton("Single");
buttonSingle.setAlignmentX(Component.CENTER_ALIGNMENT);
buttonSingle.addActionListener(new ActionListener(){
#Override
public void actionPerformed(ActionEvent e) {
}
});
add(buttonSingle);
add(Box.createVerticalGlue());
JButton buttonMulti = new JButton("Multiplayer");
buttonMulti.setAlignmentX(Component.CENTER_ALIGNMENT);
buttonMulti.addActionListener(new ActionListener(){
#Override
public void actionPerformed(ActionEvent e) {
throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.
}
});
add(buttonMulti);
add(Box.createVerticalGlue());
JButton buttonExit = new JButton("Wyjście");
buttonExit.setAlignmentX(Component.CENTER_ALIGNMENT);
buttonExit.addActionListener(new ActionListener(){
#Override
public void actionPerformed(ActionEvent e) {
System.exit(0);
}});
add(buttonExit);
add(Box.createVerticalGlue());
}
}
my SinglePanel class
public class SinglePanel extends JPanel{
SinglePanel(){
setLayout(new FlowLayout());
JButton powrot = new JButton("Wróć do menu");
powrot.addActionListener(new ActionListener(){
#Override
public void actionPerformed(ActionEvent e) {
}
});
add(powrot);
}
}
Main class:
public class Main {
/**
* #param args the command line arguments
*/
public static void main(String[] args) {
// TODO code application logic here
/*MainMenu mM = new MainMenu();*/
Frame f = new Frame();
}
}
You need a reference to the CardLayout of the JFrame inside your panel classes. What you can do is pass the Frame to the JPanel classes as reference, then you can use the CardLayout of the Frame in those classes to show or next etc. Something like
public class MainMenu {
private CardLayout layout;
private Frame frame;
public MainMenu(final Frame frame) {
this.frame = frame;
this.layout = (CardLayout)frame.getLayout();
JButton buttonSingle = new JButton("Single");
buttonSingle.setAlignmentX(Component.CENTER_ALIGNMENT);
buttonSingle.addActionListener(new ActionListener(){
#Override
public void actionPerformed(ActionEvent e) {
layout.show(frame, "single");
}
});
}
}
When you create the MainPanel, you need to pass Frame.this to it, referencing the current Frame
MainMenu menuPanel = new MainMenu(Frame.this);
EDIT
I just noticed your swapView method. So instead of use the CardLayout directly in the panel class, you can actually just call swapView in the actionPerformed
frame.swapView("single");
Or better yet, as to not expose the Frame class, you can have the Frame class implement an interface say SwapInterface that has a method swapView you need to override. And pass the SwapInterface to the panel classes. Something like
public interface SwapInterface {
public void swapView(String view);
}
public Frame extends JFrame implements SwapInterface {
MainMenu mainPanel = new MainMenu(Frame.this);
....
#Override
public void swapView(String view) {
cl.show(getContentPane(), view);
}
}
public class MainMenu extends JPanel {
private SwapInterface swap;
public MainMenu(SwapInterface swap) {
this.swap = swap;
...
public void actionPerfomed(ActionEvent e) {
swap.swapView("single");
}
}
}
Side Note
As HovercraftFullOfEels pointed out in his comment, you should make use of String contants for the String card values so there's no mistakes. Something like
private static final String SINGLE_CARD = "single";
Then in places where you use "single", use SINGLE_CARD instead
I would like to draw on sub-panels, which are created by the .form. There is one "mainPanel", which contains three subPanels named panel1(top), panel2(bottom-left) and panel3(bottom-right).
Now I would like to draw something on the subPanel "panel1", but it does not work. When I run the program, it only shows the three subPanels there, but without my drawings of the "paintComponent()" method.
I pasted my code here, could anyone help me to check what is the problem? Thanks a lot.
public class PanelDrawTest extends JFrame {
private JPanel mainPanel;
private JPanel panel1;
private JPanel panel2;
private JPanel panel3;
public PanelDrawTest(){
getContentPane().add(mainPanel);
setPanel1(new MyPanel1());
}
public JPanel getMainPanel() {
return mainPanel;
}
public JPanel getPanel1() {
return panel1;
}
public void setPanel1(JPanel panel1) {
this.panel1 = panel1;
}
private class MyPanel1 extends JPanel {
public MyPanel1(){
}
#Override
public void paintComponent(Graphics g){
g.drawString("This is Panel 1",20,20);
g.drawRect(0,200,100,200);
}
}
public static void main(String args[]){
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
createAndShowGUI();
}
});
}
private static void createAndShowGUI() {
PanelDrawTest frame = new PanelDrawTest();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setBounds(50, 50, 1200, 700);
frame.setPreferredSize(new Dimension(1200,800));
frame.pack();
frame.setVisible(true);
}
}
Note: The code posted throws a NullPointerException because mainPanel was never initialized.
The constructor is not adding your custom panel to the layout and this is why it cannot be seen.
Try this and you'll see your drawing:
public PanelDrawTest() {
mainPanel = new JPanel();
getContentPane().add(mainPanel,BorderLayout.NORTH);
panel1 = new MyPanel1();
getContentPane().add(panel1,BorderLayout.CENTER);
}
Your version wasn't runnable for me, but this works:
public class PanelDrawTest extends JFrame {
private JPanel mainPanel = new JPanel(); // I added a constructor to avoid NullPointerexception
private JPanel panel1;
private JPanel panel2;
private JPanel panel3;
public PanelDrawTest(){
getContentPane().add(mainPanel);
setPanel1(new MyPanel1());
add(panel1); // and I added the panel
}
public JPanel getMainPanel() {
return mainPanel;
}
public JPanel getPanel1() {
return panel1;
}
public void setPanel1(JPanel panel1) {
this.panel1 = panel1;
}
private class MyPanel1 extends JPanel {
public MyPanel1(){
}
#Override
public void paintComponent(Graphics g){
g.drawString("This is Panel 1",20,20);
g.drawRect(0,200,100,200);
}
}
public static void main(String args[]){
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
createAndShowGUI();
}
});
}
private static void createAndShowGUI() {
PanelDrawTest frame = new PanelDrawTest();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setBounds(50, 50, 1200, 700);
frame.setPreferredSize(new Dimension(1200,800));
frame.pack();
frame.setVisible(true);
}
}