Java Swing: JToolBar, JViewport & JFrame

Java JToolBar

JToolBar container allows us to group other components, usually buttons with icons in a row or column. JToolBar provides a component which is useful for displaying commonly used actions or controls.

Nested Classes

Modifier and Type	Class	Description
protected class	JToolBar.AccessibleJToolBar	This class implements accessibility support for the JToolBar class.
static class	JToolBar.Separator	A toolbar-specific separator.

Constructors

Constructor	Description
JToolBar()	It creates a new tool bar; orientation defaults to HORIZONTAL.
JToolBar(int orientation)	It creates a new tool bar with the specified orientation.
JToolBar(String name)	It creates a new tool bar with the specified name.
JToolBar(String name, int orientation)	It creates a new tool bar with a specified name and orientation.

Useful Methods

Modifier and Type	Method	Description
JButton	add(Action a)	It adds a new JButton which dispatches the action.
protected void	addImpl(Component comp, Object constraints, int index)	If a JButton is being added, it is initially set to be disabled.
void	addSeparator()	It appends a separator of default size to the end of the tool bar.
protected PropertyChangeListener	createActionChangeListener(JButton b)	It returns a properly configured PropertyChangeListener which updates the control as changes to the Action occur, or null if the default property change listener for the control is desired.
protected JButton	createActionComponent(Action a)	Factory method which creates the JButton for Actions added to the JToolBar.
ToolBarUI	getUI()	It returns the tool bar's current UI.
void	setUI(ToolBarUI ui)	It sets the L&F object that renders this component.
void	setOrientation(int o)	It sets the orientation of the tool bar.

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Java JToolBar Example

1. import java.awt.BorderLayout;  
2. import java.awt.Container;  
3. import javax.swing.JButton;  
4. import javax.swing.JComboBox;  
5. import javax.swing.JFrame;  
6. import javax.swing.JScrollPane;  
7. import javax.swing.JTextArea;  
8. import javax.swing.JToolBar;  
9.   
10. public class JToolBarExample {  
11.     public static void main(final String args[]) {  
12.         JFrame myframe = new JFrame("JToolBar Example");  
13.         myframe.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);  
14.         JToolBar toolbar = new JToolBar();  
15.         toolbar.setRollover(true);  
16.         JButton button = new JButton("File");  
17.         toolbar.add(button);  
18.         toolbar.addSeparator();  
19.         toolbar.add(new JButton("Edit"));  
20.         toolbar.add(new JComboBox(new String[] { "Opt-1", "Opt-2", "Opt-3", "Opt-4" }));  
21.         Container contentPane = myframe.getContentPane();  
22.         contentPane.add(toolbar, BorderLayout.NORTH);  
23.         JTextArea textArea = new JTextArea();  
24.         JScrollPane mypane = new JScrollPane(textArea);  
25.         contentPane.add(mypane, BorderLayout.EAST);  
26.         myframe.setSize(450, 250);  
27.         myframe.setVisible(true);  
28.     }  
29. }  

Java JViewport

The JViewport class is used to implement scrolling. JViewport is designed to support both logical scrolling and pixel-based scrolling. The viewport's child, called the view, is scrolled by calling the JViewport.setViewPosition() method.

Nested Classes

Modifier and Type	Class	Description
protected class	JViewport.AccessibleJViewport	This class implements accessibility support for the Jviewport class.
protected class	JViewport.ViewListener	A listener for the view.

Fields

Modifier and Type	Field	Description
static int	BACKINGSTORE_SCROLL_MODE	It draws viewport contents into an offscreen image.
protected Image	backingStoreImage	The view image used for a backing store.
static int	BLIT_SCROLL_MODE	It uses graphics.copyArea to implement scrolling.
protected boolean	isViewSizeSet	True when the viewport dimensions have been determined.
protected Point	lastPaintPosition	The last viewPosition that we've painted, so we know how much of the backing store image is valid.
protected boolean	scrollUnderway	The scrollUnderway flag is used for components like JList.
static int	SIMPLE_SCROLL_MODE	This mode uses the very simple method of redrawing the entire contents of the scrollpane each time it is scrolled.

Constructor

Constructor	Description
JViewport()	Creates a JViewport.

Methods

Modifier and Type	Method	Description
void	addChangeListener(ChangeListener l)	It adds a ChangeListener to the list that is notified each time the view's size, position, or the viewport's extent size has changed.
protected LayoutManager	createLayoutManager()	Subclassers can override this to install a different layout manager (or null) in the constructor.
protected Jviewport.ViewListener	createViewListener()	It creates a listener for the view.
int	getScrollMode()	It returns the current scrolling mode.
Component	getView()	It returns the JViewport's one child or null.
Point	getViewPosition()	It returns the view coordinates that appear in the upper left hand corner of the viewport, or 0,0 if there's no view.
Dimension	getViewSize()	If the view's size hasn't been explicitly set, return the preferred size, otherwise return the view's current size.
void	setExtentSize(Dimension newExtent)	It sets the size of the visible part of the view using view coordinates.
void	setScrollMode(int mode)	It used to control the method of scrolling the viewport contents.
void	setViewSize(Dimension newSize)	It sets the size of the view.

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JViewport Example

1. import java.awt.BorderLayout;  
2. import java.awt.Color;  
3. import java.awt.Dimension;  
4. import javax.swing.JButton;  
5. import javax.swing.JFrame;  
6. import javax.swing.JLabel;  
7. import javax.swing.JScrollPane;  
8. import javax.swing.border.LineBorder;  
9. public class ViewPortClass2 {  
10.     public static void main(String[] args) {  
11.         JFrame frame = new JFrame("Tabbed Pane Sample");  
12.         frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);  
13.   
14.         JLabel label = new JLabel("Label");  
15.         label.setPreferredSize(new Dimension(1000, 1000));  
16.         JScrollPane jScrollPane = new JScrollPane(label);  
17.   
18.         JButton jButton1 = new JButton();  
19.         jScrollPane.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);  
20.         jScrollPane.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);  
21.         jScrollPane.setViewportBorder(new LineBorder(Color.RED));  
22.         jScrollPane.getViewport().add(jButton1, null);  
23.   
24.         frame.add(jScrollPane, BorderLayout.CENTER);  
25.         frame.setSize(400, 150);  
26.         frame.setVisible(true);  
27.     }  
28. }  

Output:

Java JFrame

The javax.swing.JFrame class is a type of container which inherits the java.awt.Frame class. JFrame works like the main window where components like labels, buttons, textfields are added to create a GUI.

Unlike Frame, JFrame has the option to hide or close the window with the help of setDefaultCloseOperation(int) method.

Nested Class

Modifier and Type	Class	Description
protected class	JFrame.AccessibleJFrame	This class implements accessibility support for the JFrame class.

Fields

Modifier and Type	Field	Description
protected AccessibleContext	accessibleContext	The accessible context property.
static int	EXIT_ON_CLOSE	The exit application default window close operation.
protected JRootPane	rootPane	The JRootPane instance that manages the contentPane and optional menuBar for this frame, as well as the glassPane.
protected boolean	rootPaneCheckingEnabled	If true then calls to add and setLayout will be forwarded to the contentPane.

Constructors

Constructor	Description
JFrame()	It constructs a new frame that is initially invisible.
JFrame(GraphicsConfiguration gc)	It creates a Frame in the specified GraphicsConfiguration of a screen device and a blank title.
JFrame(String title)	It creates a new, initially invisible Frame with the specified title.
JFrame(String title, GraphicsConfiguration gc)	It creates a JFrame with the specified title and the specified GraphicsConfiguration of a screen device.

Useful Methods

Modifier and Type	Method	Description
protected void	addImpl(Component comp, Object constraints, int index)	Adds the specified child Component.
protected JRootPane	createRootPane()	Called by the constructor methods to create the default rootPane.
protected void	frameInit()	Called by the constructors to init the JFrame properly.
void	setContentPane(Containe contentPane)	It sets the contentPane property
static void	setDefaultLookAndFeelDecorated(boolean defaultLookAndFeelDecorated)	Provides a hint as to whether or not newly created JFrames should have their Window decorations (such as borders, widgets to close the window, title...) provided by the current look and feel.
void	setIconImage(Image image)	It sets the image to be displayed as the icon for this window.
void	setJMenuBar(JMenuBar menubar)	It sets the menubar for this frame.
void	setLayeredPane(JLayeredPane layeredPane)	It sets the layeredPane property.
JRootPane	getRootPane()	It returns the rootPane object for this frame.
TransferHandler	getTransferHandler()	It gets the transferHandler property.

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JFrame Example

1. import java.awt.FlowLayout;  
2. import javax.swing.JButton;  
3. import javax.swing.JFrame;  
4. import javax.swing.JLabel;  
5. import javax.swing.Jpanel;  
6. public class JFrameExample {  
7.     public static void main(String s[]) {  
8.         JFrame frame = new JFrame("JFrame Example");  
9.         JPanel panel = new JPanel();  
10.         panel.setLayout(new FlowLayout());  
11.         JLabel label = new JLabel("JFrame By Example");  
12.         JButton button = new JButton();  
13.         button.setText("Button");  
14.         panel.add(label);  
15.         panel.add(button);  
16.         frame.add(panel);  
17.         frame.setSize(200, 300);  
18.         frame.setLocationRelativeTo(null);  
19.         frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);  
20.         frame.setVisible(true);  
21.     }  
22. }  

Output

Anurag Rana Educator CSE/IT