GUI Basics: Introduction

Creating GUI Objects// Create a button with text OK JButton jbtOK = new JButton("OK");  // Create a label with text "Enter your name: "JLabel jlblName = new JLabel("Enter your name: ");  

// Create a text field with text "Type Name Here"JTextField jtfName = new JTextField("Type Name Here");  // Create a check box with text boldJCheckBox jchkBold = new JCheckBox("Bold");  // Create a radio button with text redJRadioButton jrbRed = new JRadioButton("Red");  // Create a combo box with choices red, green, and blueJComboBox jcboColor = new JComboBox(new String[]{"Red", "Green", "Blue"});

Button

Label Text field

Check Box

Radio Button

Combo Box

Swing vs. AWTThe biggest difference between the AWT components and Swing components are:

Swing components are implemented with absolutely no native code. Native code is methods implemented in another programming language such as C .

Swing features are present on every platform. Swing can have more functionality than AWT

components. Swing can be shipped as an add-on to JDK 1.1, in addition

to being part of the Java 2 Platform.

Swing vs. AWTSwing components have capabilities far beyond what the AWT components offer:

Swing buttons and labels can display images instead of, or in addition to, text.

You can easily add or change the borders drawn around most Swing components. For example, it's easy to put a box around the outside of a container or label.

You can easily change the behavior or appearance of a Swing component by either invoking methods on it or creating a subclass of it.

Swing components don't have to be rectangular. Buttons, for example, can be round.

GUI Class Hierarchy (Swing)

Dimension

Font

FontMetrics

Component

Graphics

Object Color

Container

Panel Applet

Frame

Dialog

Window

JComponent

JApplet

JFrame

JDialog

Swing Components in the javax.swing package

Lightweight

Heavyweight

Classes in the java.awt package

1

LayoutManager

*

Container Classes

Dimension

Font

FontMetrics

Component

Graphics

Object Color

Container

Panel Applet

Frame

Dialog

Window

JComponent

JApplet

JFrame

JDialog

Swing Components in the javax.swing package

Lightweight

Heavyweight

Classes in the java.awt package

1

LayoutManager

*

JPanel Container classes can contain other GUI components.

Dimension

Font

FontMetrics

Component

Graphics

Object Color

Container

Panel Applet

Frame

Dialog

Window

JComponent

JApplet

JFrame

JDialog

Swing Components in the javax.swing package

Lightweight

Heavyweight

Classes in the java.awt package

1

LayoutManager

*

JPanel The helper classes are not subclasses of Component. They are used to describe the properties of GUI components such as graphics context, colors, fonts, and dimension.

GUI Helper Classes

Swing GUI Components

JMenuItem

JCheckBoxMenuItem

AbstractButton

JComponent

JMenu

JRadioButtonMenuItem

JToggleButton JCheckBox

JRadioButton

JComboBox

JInternalFrame

JLayeredPane

JList

JMenuBar

JOptionPane

JPopupMenu

JProgressBar

JFileChooser

JScrollBar

JScrollPane JSeparator JSplitPane

JSlider

JTabbedPane

JTable JTableHeader

JTextField JTextComponent

JTextArea

JToolBar JToolTip

JTree

JRootPane

JPanel

JPasswordField

JColorChooser

JLabel

JEditorPane

JSpinner

JButton

Components Covered in the Core Version

JMenuItem

JCheckBoxMenuItem

AbstractButton

JComponent

JMenu

JRadioButtonMenuItem

JToggleButton JCheckBox

JRadioButton

JComboBox

JInternalFrame

JLayeredPane

JList

JMenuBar

JOptionPane

JPopupMenu

JProgressBar

JFileChooser

JScrollBar

JScrollPane JSeparator JSplitPane

JSlider

JTabbedPane

JTable JTableHeader

JTextField JTextComponent

JTextArea

JToolBar JToolTip

JTree

JRootPane

JPanel

JPasswordField

JColorChooser

JLabel

JEditorPane

JSpinner

JButton

Components Covered in the Comprehensive Version

JMenuItem

JCheckBoxMenuItem

AbstractButton

JComponent

JMenu

JRadioButtonMenuItem

JToggleButton JCheckBox

JRadioButton

JComboBox

JInternalFrame

JLayeredPane

JList

JMenuBar

JOptionPane

JPopupMenu

JProgressBar

JFileChooser

JScrollBar

JScrollPane JSeparator JSplitPane

JSlider

JTabbedPane

JTable JTableHeader

JTextField JTextComponent

JTextArea

JToolBar JToolTip

JTree

JRootPane

JPanel

JPasswordField

JColorChooser

JLabel

JEditorPane

JSpinner

JButton

AWT (Optional)AWTEvent

Font

FontMetrics

Component

Graphics

Object Color

Canvas

Button

TextComponent

Label

List

CheckBoxGroup

CheckBox

Choice

Container Panel Applet

Frame

Dialog FileDialog

Window

TextField

TextArea

MenuComponent MenuItem

MenuBar

Menu

Scrollbar

LayoutManager

Frames

Frame is a window that is not contained inside another window. Frame is the basis to contain other user interface components in Java GUI applications.

The JFrame class can be used to create windows.

For Swing GUI programs, use JFrame class to create widows.

Creating Framesimport javax.swing.*;public class MyFrame { public static void main(String[] args) { JFrame frame = new JFrame("Test Frame"); frame.setSize(400, 300); frame.setVisible(true); frame.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE); }

}

Adding Components into a Frame

// Add a button into the frameframe.getContentPane().add( new JButton("OK"));

Title bar

Content pane

import javax.swing.*; public class MyFrameWithComponents { public static void main(String[] args) {

JFrame frame = new JFrame("MyFrameWithComponents"); // Add a button into the frame JButton jbtOK = new JButton("OK"); frame.add(jbtOK); frame.setSize(400, 300); frame.setVisible(true); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.setLocationRelativeTo(null); // New since JDK 1.4 }

}

Content Pane Delegation in JDK 1.5

// Add a button into the frameframe.getContentPane().add( new JButton("OK"));

Title bar

Content pane// Add a button into the frameframe.add( new JButton("OK"));

JFrame Class

javax.swing.JFrame

+JFrame()

+JFrame(title: String)

+getSize(width: int, height: int): void

+setLocation(x: int, y: int): void

+setVisible(visible: boolean): void

+setDefaultCloseOperation(mode: int): void

+setLocationRelativeTo (c: Component): void

Creates a default frame with no title.

Creates a frame with the specified title.

Specifies the size of the frame.

Specifies the upper-left corner location of the frame.

Sets true to display the frame.

Specifies the operation when the frame is closed.

Sets the location of the frame relative to the specified component. If the component is null, the frame is centered on the screen.

Layout Managers Java’s layout managers provide a level of abstraction to

automatically map your user interface on all window systems.

The UI components are placed in containers. Each container has a layout manager to arrange the UI components within the container.

Layout managers are set in containers using the setLayout(LayoutManager) method in a container.

Kinds of Layout Managers

FlowLayout

GridLayout

BorderLayout