Develop Reference

Java GUI switching between panels on button click

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.

Java Button disappears after clicking

I'm trying to add a button using an JOptionPane in another button, but after I clicked the original button just keeps disappearing.
I've tried adding the JPanel manually instead of using 'handPanelNPC.getHandPanel()' by iterating through the handPanel.buttons but it stil wont work. I've checked the ArrayList size and it is already inserted properly.
LayoutTesting.java
public class LayoutTesting extends JFrame{
HandPanel handPanelNPC = new HandPanel();
public LayoutTesting(HandPanel handPanel, int type){
Container pane = getContentPane();
if (type==1){
handPanelNPC = handPanel;
}
pane.setLayout(new BorderLayout());
pane.add(handPanelNPC.getHandPanel(), BorderLayout.NORTH);
validate();
repaint();
}
public LayoutTesting(){
Container pane = getContentPane();
pane.setLayout(new BorderLayout());
pane.add(handPanelNPC.getHandPanel(), BorderLayout.NORTH);
}
}
HandPanel.java
public class HandPanel implements ActionListener{
JFrame frame = null;
JPanel panel = new JPanel();
ArrayList<JButton> buttons = new ArrayList<JButton>();
public HandPanel(){
addNewButton();
panel.setLayout(new FlowLayout());
panel.add(buttons.get(0));
}
public JComponent getHandPanel(){
panel = new JPanel();
for(int i=0; i<buttons.size(); i++){
JButton button = buttons.get(i);
panel.add(button);
}
return panel;
}
public void addNewButton(){
JButton button = new JButton();
button.setPreferredSize(new Dimension(40,58));
button.addActionListener(this);
buttons.add(button);
}
public void actionPerformed(ActionEvent e) {
String[] options = {"Summon", "Set", "Add Card"};
int messageType = JOptionPane.QUESTION_MESSAGE;
int code = JOptionPane.showOptionDialog(
frame,
"What would you like to do?",
"Card Name",
0, messageType, null,
options, options[1]);
if (code==2){
addNewButton();
LayoutTesting frame = new LayoutTesting(this, 1);
}
}
}
Main.java
public class Main extends JFrame{
public static void main(String[] args){
LayoutTesting frame = new LayoutTesting();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(400, 300);
frame.setVisible(true);
}
}

You have too many odd things happening in your code to give a simple answer.
Try debugging your own code by looking at this line in HandPanel.java:
LayoutTesting frame = new LayoutTesting(this, 1);
What does it really do? Now remove that line and the button will not disappear. Now try and work out what that line was doing, and why the button disappeared.
Also 'panel.add(buttons.get(0));' does nothing because there is never a button in the array when you make that call (You add the button afterwards in another method).
Here is a rough working demo that lets you add as many new cards as you want to the first frame, and each card has a button that will let you summon a new card.
public class LayoutTesting extends JFrame{
Container pane;
//Add card when button is pressed:
public void addCard(){
Container card = new JPanel();
card.setBackground(Color.red);
JButton newButton = addNewButton();
newButton.setBackground(Color.red);
card.add(newButton);
pane.add(card);
revalidate();
repaint();
}
//Setup window and add button:
public LayoutTesting(){
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setSize(400, 300);
setVisible(true);
setLayout(new FlowLayout());
pane = new JPanel();
pane.setLayout(new GridBagLayout());
JButton firstButton = addNewButton();
firstButton.setBackground(Color.green);
add(pane);
add(firstButton);
}
//Create button and action listener:
public JButton addNewButton(){
JButton button = new JButton();
button.setPreferredSize(new Dimension(40, 58));
button.addActionListener(new java.awt.event.ActionListener(){
#Override
public void actionPerformed(java.awt.event.ActionEvent evt){
buttonAction(evt);
}
});
return button;
}
//Action fer each button:
public void buttonAction(ActionEvent e) {
String[] options = {"Summon", "Set", "Add Card"};
int messageType = JOptionPane.QUESTION_MESSAGE;
int code = JOptionPane.showOptionDialog(
this,
"What would you like to do?",
"Card Name",
0, messageType, null,
options, options[1]);
if (code==2){
addCard();
}
}
}

cannot add dynamic jtextfields and save their values

In previos my questions I asked similar questions to this. But in my previous projects I used GUI builder, so now I would like to add JTextField to the Panel dynamically without Builder. I don't why but for some reason I cannot execute this code:
public class Reference {
JFrame frame = new JFrame();
JPanel MainPanel = new JPanel();
MainPanel main = new MainPanel();
JPanel SubPanel = new JPanel();
JButton addButton = new JButton();
JButton saveButton = new JButton();
private List<JTextField> listTf = new ArrayList<JTextField>();
/**
* #param args the command line arguments
*/
public static void main(String[] args) {
new Reference();
}
public Reference() {
frame.add(main);
frame.setLayout(new BorderLayout());
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(addButton, BorderLayout.EAST);
frame.add(saveButton, BorderLayout.WEST);
frame.pack();
frame.setSize(500, 300);
frame.setVisible(true);
main.setLayout(new BorderLayout());
main.setBackground(Color.green);
main.add(SubPanel);
SubPanel.setBackground(Color.yellow);
addButton.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent evt) {
main.add(new SubPanel());
main.revalidate();
}
});
saveButton.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent evt) {
for (int i = 0; i < main.getComponentCount();) {
SubPanel panel = (SubPanel)main.getComponent(i);
JTextField firstName = panel.getFirstName();
String text = firstName.getText();
System.out.println( text );
}}
});
}
private class SubPanel extends JPanel {
JTextField firstName = new JTextField(15);
public SubPanel() {
this.setLayout(new BoxLayout(this, BoxLayout.LINE_AXIS));
this.add(firstName);
listTf.add(firstName);
}
public JTextField getFirstName()
{
return firstName;
}
}
public class MainPanel extends JPanel
{
List<SubPanel> subPanels = new ArrayList<SubPanel>();
public MainPanel()
{
}
public void addSubPanel()
{
SubPanel panel = new SubPanel();
add(panel);
subPanels.add(panel);
}
public SubPanel getSubPanel(int index)
{
return subPanels.get(index);
}
}
}
And by saveButton trying to get value of JTextField, but without success. In output I can see just JFrame with 2 Buttons, but ActionListener of addButton and saveButton is not active. I cannot understand where is wrong.
Any help would be much appreciated.

In Swing, the order you do some things is very important, for example...
frame.add(main);
frame.setLayout(new BorderLayout());
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(addButton, BorderLayout.EAST);
frame.add(saveButton, BorderLayout.WEST);
frame.pack();
frame.setSize(500, 300);
frame.setVisible(true);
You add main to your frame
You set the frames layout (!?)
You add your buttons
You pack the frame
You set it's size (!?)
You make it visible
The problem here is step #2. If, instead, we simply remove step #2 (step #4 and #5 aren't great either), you will find that your window now contains main...
frame.add(main);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(addButton, BorderLayout.EAST);
frame.add(saveButton, BorderLayout.WEST);
frame.pack();
frame.setVisible(true);
This...
for (int i = 0; i < main.getComponentCount();) {
SubPanel panel = (SubPanel) main.getComponent(i);
a bad idea of three reasons;
Your loop will never advance (i will always be 0)
You are blindly casting the contents of main without actually knowing what's on it
MainPanel already has a List of SubPanels...
You need to make sure that you are adding SubPanels via the addSubPanel method (and this should probably return an instance of the SubPanel) and provide a means by which you can access this List, maybe via a getter of some sort. Although, I'd be more interested in their values (ie the text field text) rather then the SubPanel itself ;)

Working with JFrames

hi I'm basically give up. Ok so this is what I am trying to do. So far I have written code to create a JFrame which contains a text field and combo box. The code is supposed to calculate the area of an input in the text field depending on what shape is selected from the combo box and output the result on the JFrame!
Here's is what the output should look like
And here is my code so far. it's a bit messed up but any help would be much appreciated. Thanks in advance
import javax.swing. *;
import java.awt.event. *;
import java.awt.FlowLayout;
import java.lang.Math;
public class AreaFrame3 extends JFrame
{
double Area;
double input;
public static void main(String[]args)
{
//Create array containing shapes
String[] shapes ={"(no shape selected)","Circle","Equilateral Triangle","Square"};
//Use combobox to create drop down menu
JComboBox comboBox=new JComboBox(shapes);
JLabel label1 = new JLabel("Select shape:");
JPanel panel1 = new JPanel(new FlowLayout()); //set frame layout
JLabel label2 = new JLabel("(select shape first)");
JTextField text = new JTextField(10); //create text field
text.setEnabled(false);
panel1.add(label1);
panel1.add(comboBox);
panel1.add(label2);
panel1.add(text);
JFrame frame=new JFrame("Area Calculator Window");//create a JFrame to put combobox
frame.setLayout(new FlowLayout()); //set layout
frame.add(panel1);
frame.add(text);
//JButton button = new JButton("GO"); //create GO button
//frame.add(button);
//set default close operation for JFrame
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
//set JFrame ssize
frame.setSize(400,250);
//make JFrame visible. So we can see it
frame.setVisible(true);
// public void actionPerformed(ActionEvent e)
//{
}
public void AreaCalc()
{
JButton button = new JButton("GO"); //create GO button
frame.add(button);
button.addActionListener(
new ActionListener(){
public void actionPerformed(ActionEvent e)
{
int input = double.parseDouble(text.getText());
if(e.getSource() == button)
{
String shape = (String).comboBox.getSelectedItem();
if(shape == "(no shape selected)")
{
text.setEnabled(false);
}
else{
text.setEnabled(true);
}
if(input > 1 && shape == "Circle")
{
// label2.getText() = "Enter the radius of the circle: ";
Area = (Math.PI * (input * input));
}
}
else{}
}
}
);
}
}

I try to understand what you did here:
panel1.add(label1);
panel1.add(comboBox);
panel1.add(label2);
panel1.add(text); // <---
JFrame frame=new JFrame("Area Calculator Window");//create a JFrame to put combobox
frame.setLayout(new FlowLayout()); //set layout
frame.add(panel1);
frame.add(text); // <---
Especially frame.add(text); and panel1.add(text);. Don't add text to JFrame. Use JPanel.
Further,
public class AreaFrame3 extends Frame
Use public class AreaFrame3 extends JFrame so you don't need create additional JFrame:
JFrame frame=new JFrame("Area Calculator Window");
Something like:
super.setLayout(new FlowLayout()); //set layout
super.add(panel1);
super.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
super.pack();
//set JFrame ssize
super.setSize(400,250);
//make JFrame visible. So we can see it
super.setVisible(true);
At last Ill give you some tamplate to start with (that will help you):
public class FrameExmpl extends JFrame{
private static final long serialVersionUID = 1L;
private JTabbedPane tabbedPane;
private JPanel topPanel;
private JTextField txtf_loadDS_;
public static int valueInt = 0; // responsible for Task status updating
public static Boolean isFinish = false;
public static void main(String[] args) throws ClassNotFoundException, InstantiationException, IllegalAccessException, UnsupportedLookAndFeelException{
UIManager.setLookAndFeel( "com.sun.java.swing.plaf.windows.WindowsLookAndFeel" );
FrameExmpl UI_L = new FrameExmpl();
UI_L.buildGUI();
UI_L.setVisible(true);
}
public void buildGUI(){
addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
dispose();
}
});
setSize(435, 225);
setLocation(285, 105);
setResizable(false);
topPanel = new JPanel();
topPanel.setLayout(new BorderLayout());
getContentPane().add(topPanel);
txtf_loadDS_ = new JTextField();
txtf_loadDS_.setBounds(22, 22, 382, 25);
topPanel.add(txtf_loadDS_);
finishBuildGUI();
}
public void finishBuildGUI(){
tabbedPane = new JTabbedPane();
topPanel.add(tabbedPane, BorderLayout.CENTER);
}
}

There are multiple issues with this application such as extending from Frame rather than JFrame & attempting to assign an int from Double.parseDouble. I would recommend that you start again building a small but working application and incrementally add functionality, this way errors are easier to fix.

Add Jpanel to Jframe NetBeans

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.