Develop Reference

How can i use multiple panels with different layouts for my gui?

i have problems with nesting 2 different button panels into my main panel. It worked for me with only one 1 panel. Now with my actual nesting i see the last added panel over my main panel and my first button panel. Additionally the "editButton" i added, is not showing up. I got no errors while compiling. It seems to be that i just made a mistake in the arrangement.
Would be very nice if there are any suggestions. Here is my code snippet:
Thanks in advance!
private final String name;
private JLabel catLabel;
private JButton cat1Button;
private JButton cat2Button;
private JButton cat3Button;
private JButton cat4Button;
private JButton editButton;
private JButton deleteButton;
private JButton insertButton;
public JPanel panelMain;
public JPanel panel;
public JPanel panel1;
public ReadwriteQuiz readwrite;
public GUIEdit(String name){
this.name = name;
this.setTitle(name);
this.setLocationRelativeTo(null);
this.setLayout((null));
this.setSize(400,300);
this.setLocation(400,150);
this.setResizable(false);
panelMain = new JPanel();
panelMain.setLayout(new BoxLayout(panelMain, BoxLayout.Y_AXIS));
panel = new JPanel();
panel.setLayout(new FlowLayout());
panel.setBackground(Color.lightGray);
panel1 = new JPanel();
panel1.setLayout(new BoxLayout(panel1, BoxLayout.X_AXIS));
panel1.setBackground(Color.ORANGE);
panelMain.add(panel);
panelMain.add(panel1);
catLabel= new JLabel("Willkommen zum Quizzeln ! \n Wählen Sie Ihre Kategorie");
catLabel.setBounds(90,10,260,40);
panel.add(catLabel);
cat1Button = new JButton("Kategorie 1");
cat1Button.setBounds(52,90,120,40);
panel.add(cat1Button);
cat1Button.addActionListener((e) -> {
try {
readwrite.readFile("kategorie1.txt");
} catch (FileNotFoundException fileNotFoundException) {
fileNotFoundException.printStackTrace();
}
});
cat2Button = new JButton("Kategorie 2");
cat2Button.setBounds(220,90,120,40);
panel.add(cat2Button);
cat3Button = new JButton("Kategorie 3");
cat3Button.setBounds(52,160,120,40);
panel.add(cat3Button);
cat4Button = new JButton("Kategorie 4");
cat4Button.setBounds(220,160,120,40);
panel.add(cat4Button);
editButton = new JButton("Frage editieren");
editButton.setBounds(52,400,120,40);
panel1.add(editButton);
this.add(panelMain);
this.add(panel);
this.add(panel1);
this.setDefaultCloseOperation(EXIT_ON_CLOSE);
}
#Override
public void actionPerformed(ActionEvent e) {
}

You have one main panel and you have already added the other nested panels to the main panel
so you only add that main panel to the parent panel
but you're adding the main panel ( including the other 2 ) and again adding the 1st panel and again adding the 2nd panel
so
this.add(panelMain);
should be enough
Full class
public class app {
private JTextField textField1;
private JPanel panel;
private JLabel label;
private JLabel catLabel;
private JButton cat1Button;
private JButton cat2Button;
private JButton cat3Button;
private JButton cat4Button;
private JButton editButton;
private JButton deleteButton;
private JButton insertButton;
public JPanel panelMain;
public JPanel panel2;
public JPanel panel1;
public app(JFrame frame) {
panelMain = new JPanel();
panelMain.setLayout(new BoxLayout(panelMain, BoxLayout.Y_AXIS));
panel2 = new JPanel();
panel2.setLayout(new FlowLayout());
panel2.setBackground(Color.lightGray);
panel1 = new JPanel();
panel1.setLayout(new BoxLayout(panel1, BoxLayout.X_AXIS));
panel1.setBackground(Color.ORANGE);
panelMain.add(panel2);
panelMain.add(panel1);
catLabel= new JLabel("Willkommen zum Quizzeln ! \n Wählen Sie Ihre Kategorie");
catLabel.setBounds(90,10,260,40);
panel2.add(catLabel);
cat1Button = new JButton("Kategorie 1");
cat1Button.setBounds(52,90,120,40);
panel2.add(cat1Button);
cat2Button = new JButton("Kategorie 2");
cat2Button.setBounds(220,90,120,40);
panel2.add(cat2Button);
cat3Button = new JButton("Kategorie 3");
cat3Button.setBounds(52,160,120,40);
panel2.add(cat3Button);
cat4Button = new JButton("Kategorie 4");
cat4Button.setBounds(220,160,120,40);
panel2.add(cat4Button);
editButton = new JButton("Frage editieren");
editButton.setBounds(52,400,120,40);
panel1.add(editButton);
frame.add(panelMain);
}
public static void main(String[] args) {
JFrame fram = new JFrame("app");
new app(fram);
fram.pack();
fram.setVisible(true);
}
}

JPanel won't update

I've hit a problem in getting a JPanel to update.
My simple program uses a custom JPanel which displays a label and a textfield. A Jbutton on the main panel is used to replace the JPanel with a new JPanel. The initial panel shows up fine but when the button is pressed the panel is not updated with a new MyPanel. I can tell that a new object is being created as count is being incremented.
public class SwingTest extends JFrame{
private JPanel mp;
private JPanel vp;
private JButton button;
public static void main(String[] args) {
SwingTest st = new SwingTest();
}
public SwingTest() {
vp = new MyPanel();
mp = new JPanel(new BorderLayout());
mp.add(vp, BorderLayout.CENTER);
button = new JButton("Change");
button.addActionListener(new ActionListener(){
#Override
public void actionPerformed(ActionEvent ae) {
vp = new MyPanel();
vp.revalidate();
}
});
mp.add(button, BorderLayout.SOUTH);
this.add(mp);
this.setDefaultCloseOperation(DISPOSE_ON_CLOSE);
setLocationRelativeTo(null);
setSize(250, 150);
pack();
setVisible(true);
}
}
and my custom panel....
public class MyPanel extends JPanel{
private JLabel label;
private JTextField tf;
static int count = 0;
public MyPanel(){
count++;
setLayout(new GridBagLayout());
GridBagConstraints c = new GridBagConstraints();
setPreferredSize(new Dimension(400, 200));
c.gridx = 0;
c.gridy = 0;
label = new JLabel(String.valueOf(count));
tf = new JTextField(10);
add(label,c);
c.gridx = 1;
add(tf, c);
}
}

You state:
A Jbutton on the main panel is used to replace the JPanel with a new JPanel.
And yet this code:
button.addActionListener(new ActionListener(){
#Override
public void actionPerformed(ActionEvent ae) {
vp = new MyPanel();
vp.revalidate();
}
});
and yet this code does not do this at all. All it does is change the JPanel referenced by the vp variable, but has absolutely no effect on the JPanel that is being displayed by the GUI, which suggests that you're confusing reference variable with reference or object. To change the JPanel that is displayed, you must do exactly this: add the new JPanel into the container JPanel into the BorderLayout.CENTER (default) position, then call revalidate() and repaint() on the container.
e.g.,
button.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent ae) {
// vp = new MyPanel();
// vp.revalidate();
mp.remove(vp); // remove the original MyPanel from the GUI
vp = new MyPanel(); // create a new one
mp.add(vp, BorderLayout.CENTER); // add it to the container
// ask the container to layout and display the new component
mp.revalidate();
mp.repaint();
}
});
Or better still -- use a CardLayout to swap views.
Or better still -- simply clear the value held by the JTextField.
For more on the distinction between reference variable and object, please check out Jon Skeet's answer to this question: What is the difference between a variable, object, and reference?

Changing JPanels after clicking Jbutton

There are 2 JPanels in my code. The first one is Furutsu7 which is the main JPanel which includes my game. The second JPanel is the start Jbutton. What I'm trying to accomplish is after the user clicks the Jbutton, the Furutsu7 JPanel will appear.
This is my setup class where I created the buttons.
public void setup(){
JFrame f = new JFrame("Start ");
JPanel card1 = new JPanel();
JPanel card2 = new JPanel();
cards = new JPanel(new CardLayout());
JButton Card1Button = new JButton("Start");
card1.add(Card1Button);
JButton Card2Button = new JButton("Exit");
card2.add(Card2Button);
cards.add(card1, "C1");
cards.add(card2, "C2");
f.add(cards, BorderLayout.CENTER);
f.setTitle("Furutsu");
f.setSize(500, 300);
f.setLocationRelativeTo(null);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.setVisible(true);
}
What I need help on is what should I put in my action performed in order to switch to the Furutsu JPanel.
public void actionPerformed(ActionEvent e) {
}

Make your CardLayout a field of the class so that you can more easily get to it in your actionPerformed method. Otherwise you would need to call (CardLayout) cards.getLayout(), a riskier thing to do. For example:
public class MyClass implements ActionListener {
private CardLayout cardLayout = new CardLayout();
private JPanel cards = new JPanel(cardLayout);
public void setup(){
JFrame f = new JFrame("Start ");
JPanel card1 = new JPanel();
JPanel card2 = new JPanel();
// cards = new JPanel(new CardLayout());
JButton Card1Button = new JButton("Start");
card1.add(Card1Button);
JButton Card2Button = new JButton("Exit");
card2.add(Card2Button);
cards.add(card1, "C1");
cards.add(card2, "C2");
f.add(cards, BorderLayout.CENTER);
f.setTitle("Furutsu");
f.setSize(500, 300);
f.setLocationRelativeTo(null);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.setVisible(true);
}
Then you can directly refer to it:
#Override
public void actionPerformed(ActionEvent e) {
// now you can call methods on your cardLayout variable:
cardLayout.show(...); // I'll leave it to you to figure out what to put in here
}
For more on CardLayout, please check out its tutorial
Note that if you just want to swap components in forward or backwards order, look at the other methods of CardLayout, such as next(cards) and previous(cards)

Java Swing: Can't show several instances of my JPanel

I'm making a GUI and having trouble with a JPanel.
First of all here is my JPanel:
public class ExperimentPanel extends JPanel{
private static File file1,file2=null;
private static DefaultListModel model = new DefaultListModel();
private static JList list = new JList(model);
private static JPanel mainpanel = new JPanel();
private static JPanel leftpanel = new JPanel();
private static JPanel rightpanel = new JPanel();
private static JPanel twoFiles = new SelectTwoFiles();
private static JPanel folderOrFile = new SelectFolderOrFile();
private static JPanel foldersOrFiles = new SelectTwoFoldersOrFiles();
public ExperimentPanel(int selectID){
this.setBorder(new EmptyBorder(10, 10, 10, 10));
if(selectID==Constants.SelectTwoFiles){
this.add(twoFiles, BorderLayout.NORTH);
}
else if(selectID==Constants.SelectFolderOrFile){
this.add(folderOrFile, BorderLayout.NORTH);
}
else if(selectID==Constants.SelectTwoFoldersOrFiles){
this.add(foldersOrFiles,BorderLayout.NORTH);
}
JButton remove =new JButton("Remove Method");
JButton add = new JButton("Add Method");
JButton save = new JButton("Save list");
JButton load = new JButton("Load list");
leftpanel.add(new JScrollPane(list));
Box listOptions = Box.createVerticalBox();
listOptions.add(add);
listOptions.add(remove);
listOptions.add(save);
listOptions.add(load);
rightpanel.add(listOptions);
Box mainBox = Box.createHorizontalBox();
mainBox.add(leftpanel);
mainBox.add(rightpanel);
//mainBox.add(leftleft);
this.add(mainBox, BorderLayout.CENTER);
//start jobs
JButton start = new JButton("Launch experiment");
this.add(start,BorderLayout.PAGE_END);
start.addActionListener(launch);
add.addActionListener(adding);
remove.addActionListener(delete);
}
public static ActionListener launch = new ActionListener(){
public void actionPerformed(ActionEvent event){
//check the files
if((file1==null)||(file2==null)){
JOptionPane.showMessageDialog(null,
"A graph file is missing",
"Wrong files",
JOptionPane.ERROR_MESSAGE);
}
//checks the list
}
};
public static ActionListener delete = new ActionListener() {
public void actionPerformed(ActionEvent event) {
ListSelectionModel selmodel = list.getSelectionModel();
int index = selmodel.getMinSelectionIndex();
if (index >= 0)
model.remove(index);
}
};
public static ActionListener adding = new ActionListener(){
public void actionPerformed(ActionEvent event){
JComboBox combo = new JComboBox();
final JPanel cards = new JPanel(new CardLayout());
JPanel form = new JPanel();
JPanel methode1 = new JPanel();
methode1.add(new JLabel("meth1"));
methode1.setBackground(Color.BLUE);
methode1.setName("meth1");
JPanel methode2 = new JPanel();
methode2.add(new JLabel("meth2"));
methode2.setBackground(Color.GREEN);
methode1.setName("meth2");
combo.addItem("meth1");
combo.addItem("meth2");
cards.add(methode1,"meth1");
cards.add(methode2,"meth2");
JPanel control = new JPanel();
combo.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
JComboBox jcb = (JComboBox) e.getSource();
CardLayout cl = (CardLayout) cards.getLayout();
cl.show(cards, jcb.getSelectedItem().toString());
}
});
control.add(combo);
form.add(cards, BorderLayout.CENTER);
form.add(control, BorderLayout.SOUTH);
JOptionPane.showMessageDialog(null,form,"Select a method",JOptionPane.PLAIN_MESSAGE);
}
};
}
The problem is that if i create several instances of that panel they won't show like intended.
I tried creating 2 simple JFrames in my main with a new ExperimentPanel for each so the problem is not from the caller.
It works well with one JFrame calling one experiementPanel.
here is the display for one and 2 calls:
http://imgur.com/a/4DHJn
And how i call them:
JFrame test = new JFrame();
test.add(new ExperimentPanel(3));
Dimension dim = Toolkit.getDefaultToolkit().getScreenSize();
test.setLocation(dim.width/3 - test.getWidth()/3, dim.height/3 - test.getHeight()/3);
test.setSize(550,300);
test.setVisible(true);
JFrame test2 = new JFrame();
test2.add(new ExperimentPanel(3));
test2.setLocation(dim.width/3 - test.getWidth()/3, dim.height/3 - test.getHeight()/3);
test2.setSize(550,300);
test2.setVisible(true);

You create a Panel class ExperimentPanel which itself consists of several components which are stored in class fields of ExperimentPanel.
Since you declare these class fields as static there is only one instance of them. When you instantiate several ExperimentPanel objects they all want to share these fields, which leads to the effects you have seen.
Therefore remove the static modifier from these fields:
public class ExperimentPanel extends JPanel{
private File file1,file2=null;
private DefaultListModel model = new DefaultListModel();
private JList list = new JList(model);
private JPanel mainpanel = new JPanel();
private JPanel leftpanel = new JPanel();
...

BorderLayout not working JFrame

For some reason I can't get the BorderLayout to set the way it's supposed to. Just would like to know where I'm going wrong.
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class ColorFactory extends JFrame
{
final int width = 500;
final int height = 300;
private JPanel buttonPanel;
private JPanel radioButtonPanel;
private JLabel msgChangeColor;
public ColorFactory()
{
setTitle("Color Factory");
setSize(width, height);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setLayout(new BorderLayout());
createTopPanel();
add(buttonPanel, BorderLayout.NORTH);
createBottomPanel();
add(radioButtonPanel, BorderLayout.SOUTH);
msgChangeColor = new JLabel("Top buttons change the panel color and bottom radio buttons change the text color.");
add(msgChangeColor, BorderLayout.CENTER);
pack();
}
private void createTopPanel()
{
buttonPanel = new JPanel();
setLayout(new FlowLayout());
JButton redButton = new JButton("Red");
redButton.setBackground(Color.RED);
redButton.addActionListener(new ButtonListener());
redButton.setActionCommand("R");
JButton orangeButton = new JButton("Orange");
orangeButton.setBackground(Color.ORANGE);
orangeButton.addActionListener(new ButtonListener());
orangeButton.setActionCommand("O");
JButton yellowButton = new JButton("Yellow");
yellowButton.setBackground(Color.YELLOW);
yellowButton.addActionListener(new ButtonListener());
yellowButton.setActionCommand("Y");
buttonPanel.add(redButton);
buttonPanel.add(orangeButton);
buttonPanel.add(yellowButton);
}
private void createBottomPanel()
{
radioButtonPanel = new JPanel();
setLayout(new FlowLayout());
JRadioButton greenRadioButton = new JRadioButton("Green");
greenRadioButton.setBackground(Color.GREEN);
greenRadioButton.addActionListener(new RadioButtonListener());
greenRadioButton.setActionCommand("G");
JButton blueRadioButton = new JButton("Blue");
blueRadioButton.setBackground(Color.BLUE);
blueRadioButton.addActionListener(new RadioButtonListener());
blueRadioButton.setActionCommand("B");
JButton cyanRadioButton = new JButton("Cyan");
cyanRadioButton.setBackground(Color.CYAN);
cyanRadioButton.addActionListener(new RadioButtonListener());
cyanRadioButton.setActionCommand("C");
radioButtonPanel.add(greenRadioButton);
radioButtonPanel.add(blueRadioButton);
radioButtonPanel.add(cyanRadioButton);
}
private class ButtonListener implements ActionListener
{
public void actionPerformed(ActionEvent e)
{
String actionColor = e.getActionCommand();
if(actionColor.equals("R"))
{
buttonPanel.setBackground(Color.RED);
radioButtonPanel.setBackground(Color.RED);
}
if(actionColor.equals("O"))
{
buttonPanel.setBackground(Color.ORANGE);
radioButtonPanel.setBackground(Color.ORANGE);
}
if(actionColor.equals("Y"))
{
buttonPanel.setBackground(Color.YELLOW);
radioButtonPanel.setBackground(Color.YELLOW);
}
}
}
private class RadioButtonListener implements ActionListener
{
public void actionPerformed(ActionEvent e)
{
String actionTextColor = e.getActionCommand();
if(actionTextColor.equals("G"))
{
msgChangeColor.setForeground(Color.GREEN);
}
if(actionTextColor.equals("B"))
{
msgChangeColor.setForeground(Color.BLUE);
}
if(actionTextColor.equals("C"))
{
msgChangeColor.setForeground(Color.CYAN);
}
}
}
public static void main(String[] args)
{
ColorFactory run = new ColorFactory();
run.setVisible(true);
}
}

The problem is you are changing the layout manager for the frame when you create your top and bottom panels...
private void createTopPanel() {
buttonPanel = new JPanel();
setLayout(new FlowLayout()); // <--- This is call setLayout on the frame
This is why it's dangerous to...
Extend from something like JFrame directly...
Dynamically build components
It's all to easy to lose context and start effecting components you didn't actually want to...

Another problem (besides the one posted by MadProgrammer) is that you add your components to the JFrame itself.
You should add content to the content pane of the frame which you can get by calling JFrame.getContentPane().
Example:
JFrame f = new JFrame("Test");
Container c = f.getContentPane();
c.add(new JButton("In Center"), BorderLayout.CENTER);
c.add(new JButton("At the Bottom"), BorderLayout.SOUTH);
c.add(new JButton("At the Top"), BorderLayout.NORTH);
c.add(new JButton("On the Left"), BorderLayout.WEST);
c.add(new JButton("On the Right"), BorderLayout.EAST);
You can set/change the content panel by calling JFrame.setContentPane(). The default content panel already has BorderLayout so you don't even need to change it nor to set a new panel.