I would like to put the information to add in jpanel jscrollpane when you click each tree node

Question

I would like to put the information to add in jpanel jscrollpane when you click each tree node... Please...!!!

1.I want to control that state selected tree node at Tree.

Answer 1

First of all, you really don't need to extend a JTree, you're not adding any new functionality to the class (nor are you actually using it), instead, just create an instance of JTree and pass it an instance a TreeModel which models your data.

This means that you are free to add a TreeListSelection to the JTree, which will tell you when the selection changes. From the resulting TreeSelectionEvent you can get the selected path, which will tell you the components which are selected from the root to the currently selected node. You can then use getLastPathComponent to get the last node in the path (which will be the selected node).

Once you have this information, you can then make decisions about how best you should feed it to the corresponding view. Because you're using DefaultMutableTreeNode, you can associate a userObject with it, which makes it easier to store complex data with each node.

Based on your Viewer class, it would seem that the data is pretty commonailised, in that case I would consider creating POJO which maintains all the associated data and simply apply it to the DefaultMutableTreeNode, this way you can use getUserObject to extract it easily. You then simply pass this object to the Viewer panel (via some kind of setter) and let the viewer update it's own state accordingly

Have a look at How to Use Trees for more details

For example...

import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.text.DateFormat;
import java.time.LocalDate;
import java.time.Month;
import java.util.Date;
import javax.swing.JButton;
import javax.swing.JCheckBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextField;
import javax.swing.JTree;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.event.TreeSelectionEvent;
import javax.swing.event.TreeSelectionListener;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.DefaultTreeModel;
import javax.swing.tree.TreePath;

public class InterviewBrowser {

    public static void main(String[] args) {
        new InterviewBrowser();
    }

    public InterviewBrowser() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                    ex.printStackTrace();
                }

                DefaultMutableTreeNode root = new DefaultMutableTreeNode("Management");
                DefaultMutableTreeNode bigLeaf1 = new DefaultMutableTreeNode("Generl Affair");
                DefaultMutableTreeNode bigLeaf2 = new DefaultMutableTreeNode("Personal Affair");
                DefaultMutableTreeNode leaf2 = new DefaultMutableTreeNode(new InterviewHistory(
                                "Bob",
                                new Date(LocalDate.of(1972, Month.MARCH, 8).toEpochDay()),
                                Sex.MALE,
                                new Date(LocalDate.of(2015, Month.AUGUST, 10).toEpochDay()),
                                false,
                                "123456789"));
                DefaultMutableTreeNode leaf3 = new DefaultMutableTreeNode(new InterviewHistory(
                                "Jane",
                                new Date(LocalDate.of(1973, Month.JANUARY, 1).toEpochDay()),
                                Sex.FEMALE,
                                new Date(LocalDate.of(2015, Month.AUGUST, 10).toEpochDay()),
                                true,
                                "87654321"));

                bigLeaf1.add(leaf2);
                bigLeaf2.add(leaf3);
                root.add(bigLeaf1);
                root.add(bigLeaf2);
                DefaultTreeModel model = new DefaultTreeModel(root);

                JTree tree = new JTree(model);

                Viewer viewer = new Viewer();

                tree.addTreeSelectionListener(new TreeSelectionListener() {
                    @Override
                    public void valueChanged(TreeSelectionEvent e) {
                        TreePath path = e.getPath();
                        Object lastPathComponent = path.getLastPathComponent();
                        if (lastPathComponent instanceof DefaultMutableTreeNode) {
                            DefaultMutableTreeNode node = (DefaultMutableTreeNode) lastPathComponent;
                            Object userObject = node.getUserObject();
                            if (userObject instanceof InterviewHistory) {
                                InterviewHistory history = (InterviewHistory) userObject;
                                viewer.setHistory(history);
                            } else {
                                viewer.setHistory(null);
                            }
                        } else {
                            viewer.setHistory(null);
                        }
                    }
                });

                JFrame frame = new JFrame("Testing");
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.add(new JScrollPane(tree), BorderLayout.WEST);
                frame.add(viewer);
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

    public enum Sex {

        MALE,
        FEMALE
    }

    public class InterviewHistory {

        private String name;
        private Date birthDate;
        private Sex sex;
        private Date interviewDate;
        private boolean passed;
        private String phone;

        public InterviewHistory(String name, Date birthDate, Sex sex, Date interviewDate, boolean passed, String phone) {
            this.name = name;
            this.birthDate = birthDate;
            this.sex = sex;
            this.interviewDate = interviewDate;
            this.passed = passed;
            this.phone = phone;
        }

        public String getName() {
            return name;
        }

        public Date getBirthDate() {
            return birthDate;
        }

        public Sex getSex() {
            return sex;
        }

        public Date getInterviewDate() {
            return interviewDate;
        }

        public boolean didPass() {
            return passed;
        }

        public String getPhone() {
            return phone;
        }

        @Override
        public String toString() {
            return getName();
        }

    }

    public static class Viewer extends JPanel {

        public static final DateFormat DATE_FORMAT = DateFormat.getDateInstance();

        private JTextField name;
        private JTextField dateOfBirth;
        private JLabel sex;
        private JTextField dateOfInterview;
        private JCheckBox passed;
        private JTextField phone;

        public Viewer() {
            setLayout(new GridBagLayout());

            GridBagConstraints gbc = new GridBagConstraints();
            gbc.gridx = 0;
            gbc.gridy = 0;
            gbc.anchor = GridBagConstraints.WEST;

            add(new JLabel("Name: "), gbc);
            gbc.gridy++;
            add(new JLabel("Date of birth: "), gbc);
            gbc.gridy++;
            add(new JLabel("Sex: "), gbc);
            gbc.gridy++;
            add(new JLabel("Date of Interview: "), gbc);
            gbc.gridy++;
            add(new JLabel("Passed interview: "), gbc);
            gbc.gridy++;
            add(new JLabel("Phone: "), gbc);

            name = new JTextField(25);
            dateOfBirth = new JTextField(10);
            sex = new JLabel("?");
            dateOfInterview = new JTextField(10);
            passed = new JCheckBox();
            phone = new JTextField(9);

            gbc.gridx++;
            gbc.gridy = 0;

            add(name, gbc);
            gbc.gridy++;
            add(dateOfBirth, gbc);
            gbc.gridy++;
            add(sex, gbc);
            gbc.gridy++;
            add(dateOfInterview, gbc);
            gbc.gridy++;
            add(passed, gbc);
            gbc.gridy++;
            add(phone, gbc);

        }

        public void setHistory(InterviewHistory history) {
            name.setText(history == null ? null : history.getName());
            dateOfBirth.setText(history == null ? null : DATE_FORMAT.format(history.getBirthDate()));
            sex.setText(history == null ? "?" : history.getSex().name());
            dateOfInterview.setText(history == null ? null : DATE_FORMAT.format(history.getInterviewDate()));
            passed.setSelected(history == null ? false : history.didPass());
            phone.setText(history == null ? "?" : history.getPhone());
        }

    }
}

DO NOT rely on the state of static variables, it is WAY to easy for that state not to reflect reality, instead, rely on actual known values you can ascertain from the state of the view/model.

The purpose of any model is to provide a mechanism for you to display your data, you should use it to wrap your data directly, rather the trying to guess at the state of the UI or model and then look up the data separately (IMHO)