JTree Simple Practice Application in Java

Summary

JTree is a control that displays a set of hierarchical data as an outline.

We will use it as a menu to navigate through various small applications we made previously. The tree will basically contain each program as a node when selected using mouse, that particular program is displayed onto the JFrame.

Programs used in this code are already being posted before for practice, I will name the Class & the link to find the class

Reference Code

1. Simple Calculator in Java
2. Factorial Program in Java
3. Calculate Celsius to Fahrenheit Temperature in Java
4. Calculate Fahrenheit to Celsius Temperature in Java

Screenshot

Code

package com.rohansakhale.treedemo;

import java.awt.BorderLayout;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.JFrame;
import javax.swing.JTree;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.TreePath;

/**
 *
 * @author RohanSakhale
 */
public class TreeDemo {

    static String lastComponent = "";

    public static void main(String[] args) {
        final JFrame jf = new JFrame("Practice Applications");

        DefaultMutableTreeNode pracApps = new DefaultMutableTreeNode("Practice Apps", true);
        DefaultMutableTreeNode calc = new DefaultMutableTreeNode("Calculator");
        DefaultMutableTreeNode fact = new DefaultMutableTreeNode("Factorial");
        DefaultMutableTreeNode temperature = new DefaultMutableTreeNode("Temperature", true);
        DefaultMutableTreeNode c2f = new DefaultMutableTreeNode("C to F");
        DefaultMutableTreeNode f2c = new DefaultMutableTreeNode("F to C");
        temperature.add(c2f);
        temperature.add(f2c);
        pracApps.add(calc);
        pracApps.add(fact);
        pracApps.add(temperature);
        final JTree tree = new JTree(pracApps);

        // JTree here can act as a menu for Practice Applications
        // We add it on the west side of the JFrame

        jf.add(BorderLayout.WEST, tree);

        /*
         * Classes created here within the same package can also be found online
         * Calc = http://rohansakhale.com/codes/39/simple-calculator-in-java
         * Factorial = http://rohansakhale.com/codes/40/factorial-program-in-java
         * C2F = http://rohansakhale.com/codes/41/calculate-celsius-to-fahrenheit-temperature-in-java
         * F2C = http://rohansakhale.com/codes/42/calculate-fahrenheit-to-celsius-temperature-in-java
         * 
         */
        final Calc calculatorPanel = new Calc();
        final Factorial factorialPanel = new Factorial();
        final C2F c2fObj = new C2F();
        final F2C f2cObj = new F2C();

        // Lets change the panel on center of JFrame
        // by checking the mouse click
        tree.addMouseListener(new MouseAdapter() {

            @Override
            public void mouseClicked(MouseEvent me) {
                TreePath path = tree.getPathForLocation(me.getX(), me.getY());
                if (path != null) {
                    // Check the last added component and remove it
                    if (!lastComponent.equals("")) {
                        if (lastComponent.equals("Factorial")) {
                            jf.remove(factorialPanel);
                        } else if (lastComponent.equals("C to F")) {
                            jf.remove(c2fObj);
                        } else if (lastComponent.equals("Calculator")) {
                            jf.remove(calculatorPanel);
                        } else if (lastComponent.equals("F to C")) {
                            jf.remove(f2cObj);
                        }
                    }

                    // Add the new component on the frame
                    // Depending on the Selected Tree Node
                    if (path.toString().contains("Calculator")) {
                        jf.add(calculatorPanel);
                        lastComponent = "Calculator";
                    } else if (path.toString().contains("Factorial")) {
                        jf.add(factorialPanel);
                        lastComponent = "Factorial";
                    } else if (path.toString().contains("C to F")) {
                        jf.add(c2fObj);
                        lastComponent = "C to F";
                    } else if (path.toString().contains("F to C")) {
                        jf.add(f2cObj);
                        lastComponent = "F to C";
                    }
                    jf.repaint();
                }
            }
        });
        jf.setSize(600, 400);
        jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        jf.setVisible(true);
    }
}