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Swing Tutorial V

Swing Tutorial V, Learning Swing

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jinnyishere
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27 Sep, 2009 - 05:43 PM

Post #1

Remember click here for a list of the Methods and Constructor explanation

Using a Spinner

A spinner is a text field that has two little arrows next to it. A user can click one of these arrows to increase or decrease the value in the text field. Usually, the value in the text field contains a number.

Creating a Spinner

JSpinner jspin = new JSpinner();

Getting value from a spinner we use the getValue method

int value = jspin.getValue();

Creating a spinner with a specify min and max number

JSpinner hours = new JSpinner(new SpinnerNumberModel(1, 1, 12, 1));

Lets see a example on it.

CODE

/*
    The example demonstrate a simple spinner
    It allows the user to choose the time
    In addition, user can choose the am/pm

*
*/

import javax.swing.*;
import java.awt.event.*;

public class Spinner extends JFrame
{
    private JPanel panel;
    private JButton ok;
    private JSpinner spinner;

    public Spinner()
    {
        // Sets the title of the window

        setTitle("JSpinner Window");

        // Sets the size of the window

        setSize(300, 200);

        // Sets the start location of the window

        setLocationRelativeTo(null);

        // Sets the action when a window is close

        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        // Creates a spinner with initial, min, and max value

        spinner = new JSpinner(new SpinnerNumberModel(1, 1, 12, 1));

        // Creates a OK button

        ok = new JButton("OK");

        // Creates an action listener for the button

        ok.addActionListener(new okButtonListener());

        // Creates a panel

        panel = new JPanel();

        // Adds the components to the panel

        panel.add(spinner);
        panel.add(ok);

        // Adds the panel to the content pane

        add(panel);

        // Sets the visibility of the window

        setVisible(true);

    }

    private class okButtonListener implements ActionListener
    {
        public void actionPerformed(ActionEvent e)
        {
            if(e.getSource()==ok)
            {
                Object value = spinner.getValue();

                JOptionPane.showMessageDialog(null, "You have selected " + value);

            }
        }
    }

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

    }
}

Using a Tree

A tree is a more fancy swing component that displays hierarchical data in outline form. The type of tree that we most see/familiar with is the directory structure of the disk drive. Before we start to learn how to create a tree, lets learn a few terms that describe the elements in the tree.

* Node: Each element in the tree is called a node. The nodes in a tree must be created from a class that implements the TreeNode interface.

* Root node: Root node is the starting node of a tree. Every tree components must only have one root node. When we create a tree component, we pass the

root node to the JTree Constructor.

* Parent node: The node that is immediately above a given node. Every node except the root node must have only one parent node.

* Child node: The node that appear immediately below a given node. A node can have more than one child nodes.

* Leaf node: A node that doesn't have any children. It represent the end of a branch.

* Sibling nodes: Nodes that are children of the same parent.

* Path: A node and all of its ancestors such as, its parent, its parent's parent and so on all the way up to the root node.

* Collapsed node: A node whose children are hidden.

* Expanded node: A node whose children are visible.

Building a Tree

The easiest way to build a tree is to use the DefaultMutableTreeNode class, It can be found inside the link below "Swing Method & Constructor Table." Since the DefaultMutableTreeNode class implements the TreeNode interface, we can use the DefaultMutableTreenode objects for any of the methods listed in the table called for TreeNode objects.

CODE

/*
    This is a JTree program

*
*/

import javax.swing.*;
import java.awt.event.*;
import javax.swing.tree.*;
import javax.swing.event.*;

public class JTreeWindow extends JFrame
{
    private JTree tree;
    private DefaultTreeModel model;
    private JLabel name;
    private JPanel panel;

    public JTreeWindow()
    {
        // Sets the title of the window

        setTitle("JTree Window");

        // Sets the size of the window

        setSize(300, 400);

        // Sets the start location of the window

        setLocationRelativeTo(null);

        // Sets the action when the window close

        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        // Creates a panel

        panel = new JPanel();

        // Create a empty tree node

        DefaultMutableTreeNode root, Program_Files, Windows, System_32;

        // Creates the root directory

        root = new DefaultMutableTreeNode("C");

        // Adds program files, windows, and system 32 to the root directory

        Program_Files = create("Program Files", root);
        Windows = create("Program Files", root);
        System_32 = create("System 32", root);

        // Add files to the program file folder

        create("Winamp", Program_Files);
        create("JGrasp", Program_Files);
        create("Dev++", Program_Files);

        // Add files to the windows folder

        create("Window Media", Windows);
        create(".dll", Windows);
        create(".temp", Windows);

        // Add files to System 32

        create(".source", System_32);
        create("cookies", System_32);
        create("bugs", System_32);

        // Creates a tree that displays the tree that starts at the root node

        tree = new JTree(root);

        // Gets the model of the tree

        tree.getSelectionModel().setSelectionMode(TreeSelectionModel.SINGLE_TREE_SELECTION);

        // Sets the number of rows visible in the display

        tree.setVisibleRowCount(11);

        // Create an even listener for the tree

        tree.addTreeSelectionListener(new TreeListener());

        // Add a scroll pane to the tree

        JScrollPane sp = new JScrollPane(tree);

        // Create a label

        name = new JLabel();

        // Add the scroll pane and label into the panel

        panel.add(name);
        panel.add(sp);

        // Add the panel to the content pane

        add(panel);

        // Sets the visibility of the window

        setVisible(true);

    }

    private DefaultMutableTreeNode create(String title, DefaultMutableTreeNode parent)
    {
        // Creates a tree node with a specified user object

        DefaultMutableTreeNode creating = new DefaultMutableTreeNode(title);

        // Adds it to the tree

        parent.add(creating);

        return creating;

    }

    private class TreeListener implements TreeSelectionListener
    {
        public void valueChanged(TreeSelectionEvent e)
        {
            // Gets the currently selected node

            Object getSelect = tree.getLastSelectedPathComponent();

            DefaultMutableTreeNode creating = (DefaultMutableTreeNode) getSelect;

            String title = (String)creating.getUserObject();

            name.setText(title);

        }
    }

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

    }
}

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jinnyishere
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4 Oct, 2009 - 12:03 PM

Post #2

Please!! Do leave some feedbacks so i know what to improve...

is it confusing, not clear enough, needs more examples and so on..

open for any suggestions...