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javaswingjbuttonjlabel

Create different jLabels on button click

I wrote my first Java application a grocerylist. My first version worked well. If you fill out the two textfields and choose an item from the dropdown list and pressed the ADD button. The items with the amounts and units were displayed in the 2nd jPanel in a text area. But now instead of displaying it in a text area I want the items displayed in jLabels. So everytime you click the ADD button a new label should appear in the second jPanel. But I can't seem to get it to work. I read a lot of different ways here on stackoverflow and different sites on google and I read the oracle site too. But I must be doing someting wrong. Could you have a look at my code and tell me what I am doing wrong?

CODE

GroceryList2ActionListener.java 

package javaclasses;

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import grocerylist2jframe.GroceryList2JFrame;
import java.awt.Dimension;
import javax.swing.Box;
import javax.swing.JLabel;

public class GroceryList2ActionListener {

    public static class GroceryListActionListenerHandler extends GroceryList2JFrame   {
        protected static String groceryItem, unit, quantity;
        protected static JButton buttonAddGroceryItemToGrocerylist = buttonAddGroceryItem, buttonRemoveGroceryItemFromGrocerylist = buttonRemoveGroceryItem;
        protected static JLabel label;

        public static void getButtonActionAddGroceryItem() {
            buttonAddGroceryItemToGrocerylist.addActionListener(new ActionListener() {

                @Override
                public void actionPerformed(ActionEvent e) {
                    groceryItem = jTextField1GroceryItem.getText();
                    quantity = jTextField2Quantity.getText();
                    unit = jComboBox1Unit.getSelectedItem().toString();
                    label  =  new JLabel(groceryItem + " " + quantity + " " + unit + "\n");
                    label.setOpaque(true);
                    jPanel2.add(label);
                    jPanel2.add(Box.createRigidArea(new Dimension(0,5)));
                    jPanel2.revalidate();
                } 
            });
        }

        public static void main(String args[]) {

        try {
            for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
                if ("Nimbus".equals(info.getName())) {
                    javax.swing.UIManager.setLookAndFeel(info.getClassName());
                    break;
                }
            }
        } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | javax.swing.UnsupportedLookAndFeelException ex) {
            java.util.logging.Logger.getLogger(GroceryList2JFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        }

        /* Create and display the form */
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new GroceryList2JFrame().setVisible(true);
            }
        });
        getButtonActionAddGroceryItem();

        }
    }
}

GroceryList2JFrame.java

package grocerylist2jframe;


public class GroceryList2JFrame extends javax.swing.JFrame {

    public GroceryList2JFrame() {
        initComponents();
    }

    @SuppressWarnings("unchecked")                         
    private void initComponents() {

        jPanel1 = new javax.swing.JPanel();
        jPanel2 = new javax.swing.JPanel();
        jLabel2 = new javax.swing.JLabel();
        jLabel1 = new javax.swing.JLabel();
        jLabel3 = new javax.swing.JLabel();
        jComboBox1Unit = new javax.swing.JComboBox();
        jTextField2Quantity = new javax.swing.JTextField();
        jTextField1GroceryItem = new javax.swing.JTextField();
        jPanel3 = new javax.swing.JPanel();
        jPanel4 = new javax.swing.JPanel();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
        setSize(new java.awt.Dimension(0, 0));

        jPanel1.setBorder(javax.swing.BorderFactory.createTitledBorder(null, "Grocerylist2", javax.swing.border.TitledBorder.DEFAULT_JUSTIFICATION, javax.swing.border.TitledBorder.DEFAULT_POSITION, new java.awt.Font("Georgia", 3, 18))); // NOI18N
        jPanel1.setFont(new java.awt.Font("Georgia", 1, 11)); // NOI18N

        jPanel2.setBorder(javax.swing.BorderFactory.createTitledBorder(null, "Grocerylist Input", javax.swing.border.TitledBorder.DEFAULT_JUSTIFICATION, javax.swing.border.TitledBorder.DEFAULT_POSITION, new java.awt.Font("Georgia", 3, 14))); // NOI18N

        jLabel2.setFont(new java.awt.Font("Georgia", 1, 11)); // NOI18N
        jLabel2.setText("Choose a Quantity");

        jLabel1.setFont(new java.awt.Font("Georgia", 1, 11)); // NOI18N
        jLabel1.setText("Add a Grocery Item");

        jLabel3.setFont(new java.awt.Font("Georgia", 1, 11)); // NOI18N
        jLabel3.setText("Choose A Unit");

        jComboBox1Unit.setFont(new java.awt.Font("Georgia", 1, 11)); // NOI18N
        jComboBox1Unit.setModel(new javax.swing.DefaultComboBoxModel(new String[] { "Kilogram", "Gram", "Liter", "Millilitre", "Piece(s)" }));
        jComboBox1Unit.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jComboBox1UnitActionPerformed(evt);
            }
        });

        jTextField2Quantity.setFont(new java.awt.Font("Georgia", 0, 9)); // NOI18N
        jTextField2Quantity.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jTextField2QuantityActionPerformed(evt);
            }
        });

        jTextField1GroceryItem.setFont(new java.awt.Font("Georgia", 0, 9)); // NOI18N
        jTextField1GroceryItem.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jTextField1GroceryItemActionPerformed(evt);
            }
        });

        buttonAddGroceryItem.setFont(new java.awt.Font("Georgia", 1, 14)); // NOI18N
        buttonAddGroceryItem.setText("Add Grocery Item To Grocerylist");
        buttonAddGroceryItem.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                buttonAddGroceryItemActionPerformed(evt);
            }
        });

        buttonRemoveGroceryItem.setFont(new java.awt.Font("Georgia", 1, 14)); // NOI18N
        buttonRemoveGroceryItem.setText("Remove Grocery Item From Gocerylist");

        javax.swing.GroupLayout jPanel2Layout = new javax.swing.GroupLayout(jPanel2);
        jPanel2.setLayout(jPanel2Layout);
        jPanel2Layout.setHorizontalGroup(
            jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(jPanel2Layout.createSequentialGroup()
                .addGroup(jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING, false)
                    .addComponent(jLabel3, javax.swing.GroupLayout.Alignment.LEADING, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                    .addComponent(jLabel1, javax.swing.GroupLayout.Alignment.LEADING, javax.swing.GroupLayout.DEFAULT_SIZE, 135, Short.MAX_VALUE)
                    .addComponent(jLabel2, javax.swing.GroupLayout.Alignment.LEADING, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                .addGroup(jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addComponent(jTextField1GroceryItem)
                    .addComponent(jTextField2Quantity)
                    .addComponent(jComboBox1Unit, 0, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)))
            .addComponent(buttonAddGroceryItem, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
            .addComponent(buttonRemoveGroceryItem, javax.swing.GroupLayout.DEFAULT_SIZE, 338, Short.MAX_VALUE)
        );
        jPanel2Layout.setVerticalGroup(
            jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(jPanel2Layout.createSequentialGroup()
                .addGroup(jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(jLabel1, javax.swing.GroupLayout.PREFERRED_SIZE, 25, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addComponent(jTextField1GroceryItem, javax.swing.GroupLayout.PREFERRED_SIZE, 25, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addGap(10, 10, 10)
                .addGroup(jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
                    .addComponent(jLabel2, javax.swing.GroupLayout.PREFERRED_SIZE, 25, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addComponent(jTextField2Quantity, javax.swing.GroupLayout.PREFERRED_SIZE, 25, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                .addGroup(jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addComponent(jLabel3, javax.swing.GroupLayout.PREFERRED_SIZE, 25, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addComponent(jComboBox1Unit, javax.swing.GroupLayout.PREFERRED_SIZE, 25, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addGap(86, 86, 86)
                .addComponent(buttonAddGroceryItem)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
                .addComponent(buttonRemoveGroceryItem)
                .addContainerGap(217, Short.MAX_VALUE))
        );

        javax.swing.GroupLayout jPanel3Layout = new javax.swing.GroupLayout(jPanel3);
        jPanel3.setLayout(jPanel3Layout);
        jPanel3Layout.setHorizontalGroup(
            jPanel3Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGap(0, 0, Short.MAX_VALUE)
        );
        jPanel3Layout.setVerticalGroup(
            jPanel3Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGap(0, 0, Short.MAX_VALUE)
        );

        jPanel4.setBorder(javax.swing.BorderFactory.createTitledBorder(null, "Grocerylist2 View", javax.swing.border.TitledBorder.DEFAULT_JUSTIFICATION, javax.swing.border.TitledBorder.DEFAULT_POSITION, new java.awt.Font("Georgia", 1, 14))); // NOI18N

        javax.swing.GroupLayout jPanel4Layout = new javax.swing.GroupLayout(jPanel4);
        jPanel4.setLayout(jPanel4Layout);
        jPanel4Layout.setHorizontalGroup(
            jPanel4Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGap(0, 391, Short.MAX_VALUE)
        );
        jPanel4Layout.setVerticalGroup(
            jPanel4Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGap(0, 455, Short.MAX_VALUE)
        );

        javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1);
        jPanel1.setLayout(jPanel1Layout);
        jPanel1Layout.setHorizontalGroup(
            jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(jPanel1Layout.createSequentialGroup()
                .addContainerGap()
                .addComponent(jPanel2, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                .addComponent(jPanel4, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                .addComponent(jPanel3, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
        );
        jPanel1Layout.setVerticalGroup(
            jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addComponent(jPanel2, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
            .addComponent(jPanel3, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
            .addComponent(jPanel4, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
        );

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                .addComponent(jPanel1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addGap(13, 13, 13)
                .addComponent(jPanel1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                .addContainerGap())
        );

        pack();
    }// </editor-fold>                        

    private void buttonAddGroceryItemActionPerformed(java.awt.event.ActionEvent evt) {                                                     
        // TODO add your handling code here:
    }                                                    

    private void jTextField1GroceryItemActionPerformed(java.awt.event.ActionEvent evt) {                                                       
        // TODO add your handling code here:
    }                                                      

    private void jTextField2QuantityActionPerformed(java.awt.event.ActionEvent evt) {                                                    
        // TODO add your handling code here:
    }                                                   

    private void jComboBox1UnitActionPerformed(java.awt.event.ActionEvent evt) {                                               
        // TODO add your handling code here:
    } 

    // Variables declaration - do not modify                     
    public static final javax.swing.JButton buttonAddGroceryItem = new javax.swing.JButton();
    public static final javax.swing.JButton buttonRemoveGroceryItem = new javax.swing.JButton();
    public static javax.swing.JComboBox jComboBox1Unit;
    private javax.swing.JLabel jLabel1;
    private javax.swing.JLabel jLabel2;
    private javax.swing.JLabel jLabel3;
    private javax.swing.JPanel jPanel1;
    public static javax.swing.JPanel jPanel2;
    private javax.swing.JPanel jPanel3;
    public static javax.swing.JPanel jPanel4;
    public static javax.swing.JTextField jTextField1GroceryItem;
    public static javax.swing.JTextField jTextField2Quantity;
    // End of variables declaration                   
}

I added my JFrame.java. The problem is nothing is happening. There is no jLabel added. I know how to change the text of an exciting jLabel but not how to add multiple labels with the same button.

Solution

  • Your main problems areyou

    • You're trying to add components to 1) the wrong JPanel, to jPanel2 instead of the approprate jPanel4
    • Layouts: Your JPanels are using GroupLayout, a layout that doesn't like having components added in the way that you're doing it
    • Gross overuse and mis-use of statics.
    • Misuse of inheritance: Your GroceryListActionListenerHandler should most definitely not extend GroceryList2JFrame.

    Suggestions:

    • Get rid of all statics other than the main method
    • Give your jPanel4 a better layout manager, such as BoxLayout.
    • Or better still, use a JList

    For example:

    import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.KeyEvent;

import javax.swing.*;

@SuppressWarnings("serial")
public class SimpleGroceryList extends JPanel {
    private static final int JLIST_VISIBLE_ROWS = 25;
    private JTextField itemField = new JTextField(10);
    private JSpinner itemNumberSpinner = new JSpinner(new SpinnerNumberModel(1, 0, 10, 1));
    private JButton addItemButton = new JButton(new AddItemAction(this, "Add Item", KeyEvent.VK_A));
    private JPanel itemPanel = new JPanel();
    private DefaultListModel<String> listModel = new DefaultListModel<>();
    private JList<String> itemJList = new JList<>(listModel);

    public SimpleGroceryList() {
        JPanel addItemPanel = new JPanel();
        addItemPanel.add(new JLabel("Item:"));
        addItemPanel.add(itemField);
        addItemPanel.add(new JLabel("Count:"));
        addItemPanel.add(itemNumberSpinner);
        addItemPanel.add(addItemButton);

        // give jpanel a border and a decent layout that will accept jlabels well
        itemPanel.setBorder(BorderFactory.createTitledBorder("Item Panel"));
        itemPanel.setLayout(new BoxLayout(itemPanel, BoxLayout.PAGE_AXIS));

        // make the JList large
        itemJList.setVisibleRowCount(JLIST_VISIBLE_ROWS);

        setLayout(new GridLayout(1, 0));
        add(addItemPanel);
        add(new JScrollPane(itemPanel));
        add(new JScrollPane(itemJList));
    }

    // public methods that our Action can use
    public String getNewItemText() {
        return itemField.getText();
    }

    public int getNewItemCount() {
        return (int) itemNumberSpinner.getValue();
    }

    public void addNewItem(String newItem) {
        // add to jpanel
        itemPanel.add(new JLabel(newItem));
        itemPanel.revalidate();
        itemPanel.repaint();

        // add to jlist
        listModel.addElement(newItem);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(() -> {
            createAndShowGui();
        });
    }

    private static void createAndShowGui() {
        SimpleGroceryList mainPanel = new SimpleGroceryList();
        JFrame frame = new JFrame("SimpleGroceryList");
        frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
        frame.add(mainPanel);
        frame.pack();
        frame.setLocationByPlatform(true);
        frame.setVisible(true);
    }
}

@SuppressWarnings("serial")
class AddItemAction extends AbstractAction {
    private SimpleGroceryList simpleGroceryList;

    // pass the GUI into this class
    public AddItemAction(SimpleGroceryList simpleGroceryList, String name, int mnemonic) {
        super(name);  // the button's text
        putValue(MNEMONIC_KEY, mnemonic);  // the button's alt-key hot-key
        this.simpleGroceryList = simpleGroceryList; // set a field with the parameter
    }

    @Override
    public void actionPerformed(ActionEvent e) {
        // create our new item string
        String item = simpleGroceryList.getNewItemText();
        int count = simpleGroceryList.getNewItemCount();
        String newItem = item + ": " + count;

        // and pass it into gui
        simpleGroceryList.addNewItem(newItem);
    }
}