Java Tutorial/Swing/JFrame Window
Содержание
- 1 Centering a Window
- 2 Close a JFrame under condition
- 3 Constants for JFrame window close action
- 4 Creating a Borderless Window
- 5 Creating a Titleless and Borderless JFrame
- 6 Creating a Window
- 7 Creating Frames with a background image
- 8 Disabling the Close Button on a JFrame
- 9 Display a JFrame instance
- 10 Drag and move a frame from its content area
- 11 Exiting an Application When a JFrame Is Closed
- 12 Extending JFrame: Closing Frames by Default
- 13 Getting All Created Frames in an Application
- 14 Getting the Child Components of a Container
- 15 Get Top Frame
- 16 Handling JFrame Events
- 17 JFrame with Label and Window Listener to Handle Closing the Frame
- 18 Make a JFrame always visible
- 19 Make a JInternalFrame a tool window
- 20 Making a Frame Non-Resizable: use setResizable(false) to freeze a frame"s size.
- 21 Maximize a JFrame
- 22 Move JInternalFrame To Front
- 23 Preventing a Window from Gaining the Focus
- 24 Removing the Title Bar of a Frame
- 25 Resizing and positioning a JFrame
- 26 Set Default window close operation
- 27 SetIconImages for JFrame
- 28 Setting the Icon for a Frame
- 29 Sizing Windows with Toolkit
- 30 Specifying Window Decorations
- 31 Use Component listener to ensure frame visibilities
Centering a Window
<source lang="java">
import java.awt.GraphicsEnvironment; import java.awt.Point; import javax.swing.JFrame; public class CenteringaWindow {
public static void main(String[] args) {
JFrame aWindow = new JFrame("This is the Window Title");
Point center = GraphicsEnvironment.getLocalGraphicsEnvironment().getCenterPoint();
int windowWidth = 400;
int windowHeight = 150;
// set position and size
aWindow.setBounds(center.x - windowWidth / 2, center.y - windowHeight / 2, windowWidth,
windowHeight);
aWindow.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
aWindow.setVisible(true); // Display the window
}
}</source>
Close a JFrame under condition
<source lang="java">
import java.awt.event.WindowAdapter; import java.awt.event.WindowEvent; import javax.swing.JFrame; import javax.swing.JOptionPane; public class Main extends JFrame {
public Main() {
setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);
addWindowListener(new WindowAdapter() {
public void windowOpened(WindowEvent e) {
}
public void windowClosing(WindowEvent e) {
if (JOptionPane.showConfirmDialog(null, "Are you sure ?") == JOptionPane.YES_OPTION) {
setVisible(false);
dispose();
}
}
});
pack();
setVisible(true);
}
public static void main(String args[]) {
new Main();
}
}</source>
Constants for JFrame window close action
- JFrame has the setDefaultCloseOperation method to control what the JFrame"s close button does.
- The setDefaultCloseOperation method can take one of these static finals defined in the JFrame class:
- WindowConstants.DO_NOTHING_ON_CLOSE. Don"t do anything.
- WindowConstants.HIDE_ON_CLOSE (the default). Hides the frame after invoking any registered WindowListener objects.
- WindowConstants.DISPOSE_ON_CLOSE. Hides and disposes the frame after invoking any registered WindowListener objects.
- JFrame.EXIT_ON_CLOSE. Exits the application using the System.exit method.
<source lang="java">
import javax.swing.JFrame; import javax.swing.UIManager; public class SimplestFrame {
public static void main(String[] args) {
JFrame aWindow = new JFrame("This is the Window Title");
aWindow.setBounds(50, 100, 300, 300);
aWindow.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
aWindow.setVisible(true);
}
}</source>
Creating a Borderless Window
<source lang="java">
import java.awt.BorderLayout; import javax.swing.JButton; import javax.swing.JWindow; public class Main {
public static void main(String[] argv) throws Exception {
JWindow window = new JWindow();
JButton component = new JButton("asdf");
// Add component to the window
window.getContentPane().add(component, BorderLayout.CENTER);
// Set initial size
window.setSize(300, 300);
// Show the window
window.setVisible(true);
}
}</source>
Creating a Titleless and Borderless JFrame
<source lang="java">
import javax.swing.JFrame; import javax.swing.JLabel; public class Main {
public static void main(String[] args) {
JFrame frame = new JFrame("TitleLessJFrame");
frame.getContentPane().add(new JLabel(" HEY!!!"));
frame.setUndecorated(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(400, 200);
frame.setVisible(true);
}
}</source>
Creating a Window
<source lang="java">
import javax.swing.JFrame; public class CreatingAWindow {
public static void main(String[] args) {
JFrame aWindow = new JFrame("This is the Window Title");
int windowWidth = 400; // Window width in pixels
int windowHeight = 150; // Window height in pixels
aWindow.setBounds(50, 100, // Set position
windowWidth, windowHeight); // and size
aWindow.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
aWindow.setVisible(true); // Display the window
}
}</source>
Creating Frames with a background image
<source lang="java">
import java.awt.Graphics; import java.awt.Image; import java.awt.MediaTracker; import java.awt.Toolkit; import javax.swing.JFrame; import javax.swing.JPanel; public class Main extends JFrame {
Main() {
add(new ContentPanel());
setSize(500, 300);
}
public static void main(String[] args) {
Main jrframe = new Main();
jrframe.setVisible(true);
}
} class ContentPanel extends JPanel {
Image bgimage = null;
ContentPanel() {
MediaTracker mt = new MediaTracker(this);
bgimage = Toolkit.getDefaultToolkit().getImage("a.jpg");
mt.addImage(bgimage, 0);
try {
mt.waitForAll();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
protected void paintComponent(Graphics g) {
super.paintComponent(g);
int imwidth = bgimage.getWidth(null);
int imheight = bgimage.getHeight(null);
g.drawImage(bgimage, 1, 1, null);
}
}</source>
Disabling the Close Button on a JFrame
<source lang="java">
import javax.swing.JFrame; public class Main {
public static void main(String[] argv) throws Exception {
// Create a frame
JFrame frame = new JFrame();
// Get default close operation
int op = frame.getDefaultCloseOperation(); // HIDE_ON_CLOSE
// Set to ignore the button
frame.setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);
}
}</source>
Display a JFrame instance
The JFrame class has two methods that you call to display a JFrame instance, pack and setVisible.
<source lang="java">
public void pack () public void setVisible (boolean visible)</source>
Drag and move a frame from its content area
<source lang="java">
import java.awt.Color; import java.awt.Container; import java.awt.Dimension; import java.awt.Graphics; import java.awt.Point; import java.awt.event.MouseEvent; import java.awt.event.MouseListener; import java.awt.event.MouseMotionListener; import javax.swing.JComponent; import javax.swing.JFrame; import javax.swing.JPanel; public class Main extends JPanel {
public void paintComponent(Graphics g) {
g.setColor(Color.black);
g.fillRect(0, 0, getWidth(), getHeight());
}
public static void main(String[] args) {
JFrame frame = new JFrame();
frame.setPreferredSize(new Dimension(300, 280));
Main ch = new Main();
frame.getContentPane().add(ch);
frame.setUndecorated(true);
MoveMouseListener mml = new MoveMouseListener(ch);
ch.addMouseListener(mml);
ch.addMouseMotionListener(mml);
frame.pack();
frame.setVisible(true);
}
} class MoveMouseListener implements MouseListener, MouseMotionListener {
JComponent target;
Point start_drag;
Point start_loc;
public MoveMouseListener(JComponent target) {
this.target = target;
}
public static JFrame getFrame(Container target) {
if (target instanceof JFrame) {
return (JFrame) target;
}
return getFrame(target.getParent());
}
Point getScreenLocation(MouseEvent e) {
Point cursor = e.getPoint();
Point target_location = this.target.getLocationOnScreen();
return new Point((int) (target_location.getX() + cursor.getX()),
(int) (target_location.getY() + cursor.getY()));
}
public void mouseClicked(MouseEvent e) {
}
public void mouseEntered(MouseEvent e) {
}
public void mouseExited(MouseEvent e) {
}
public void mousePressed(MouseEvent e) {
this.start_drag = this.getScreenLocation(e);
this.start_loc = this.getFrame(this.target).getLocation();
}
public void mouseReleased(MouseEvent e) {
}
public void mouseDragged(MouseEvent e) {
Point current = this.getScreenLocation(e);
Point offset = new Point((int) current.getX() - (int) start_drag.getX(),
(int) current.getY() - (int) start_drag.getY());
JFrame frame = this.getFrame(target);
Point new_location = new Point(
(int) (this.start_loc.getX() + offset.getX()), (int) (this.start_loc
.getY() + offset.getY()));
frame.setLocation(new_location);
}
public void mouseMoved(MouseEvent e) {
}
}</source>
Exiting an Application When a JFrame Is Closed
<source lang="java">
import javax.swing.JFrame; public class Main {
public static void main(String[] argv) throws Exception {
// Create a frame
JFrame frame = new JFrame();
// Get default close operation
int op = frame.getDefaultCloseOperation(); // HIDE_ON_CLOSE
// Set to exit on close
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
}</source>
Extending JFrame: Closing Frames by Default
When extending JFrame, this class has two important protected methods:
<source lang="java">
protected void frameInit() protected JRootPane createRootPane()</source>
If you do override the frameInit() method of JFrame, remember to call super.frameInit() first, to initialize the default behaviors.
Getting All Created Frames in an Application
<source lang="java">
import java.awt.Frame; public class Main {
public static void main() {
Frame[] frames = Frame.getFrames();
for (int i = 0; i < frames.length; i++) {
String title = frames[i].getTitle();
System.out.println(title);
boolean isVisible = frames[i].isVisible();
System.out.println(isVisible);
}
}
}</source>
Getting the Child Components of a Container
<source lang="java">
import java.awt.ruponent; import java.awt.Rectangle; import javax.swing.JFrame; public class Main {
public static void main() {
JFrame container = new JFrame();
Component[] components = container.getComponents();
for (int i = 0; i < components.length; i++) {
Rectangle bounds = components[i].getBounds();
}
}
}</source>
Get Top Frame
<source lang="java">
/*
GNU LESSER GENERAL PUBLIC LICENSE Copyright (C) 2006 The Lobo Project This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this library; if not, write to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA Contact info: lobochief@users.sourceforge.net
- /
import java.awt.*; public class GUITasks {
public static Frame getTopFrame() {
Frame[] frames = Frame.getFrames();
for(int i = 0; i < frames.length; i++) {
if(frames[i].getFocusOwner() != null) {
return frames[i];
}
}
if(frames.length > 0) {
return frames[0];
}
return null;
}
public static void drawDashed(Graphics g, int x1, int y1, int x2, int y2, int dashSize, int gapSize) {
if(x2 < x1) {
int temp = x1;
x1 = x2;
x2 = temp;
}
if(y2 < y1) {
int temp = y1;
y1 = y2;
y2 = temp;
}
int totalDash = dashSize + gapSize;
if(y1 == y2) {
int virtualStartX = (x1 / totalDash) * totalDash;
for(int x = virtualStartX; x < x2; x += totalDash) {
int topX = x + dashSize;
if(topX > x2) {
topX = x2;
}
int firstX = x;
if(firstX < x1) {
firstX = x1;
}
if(firstX < topX) {
g.drawLine(firstX, y1, topX, y1);
}
}
}
else if(x1 == x2) {
int virtualStartY = (y1 / totalDash) * totalDash;
for(int y = virtualStartY; y < y2; y += totalDash) {
int topY = y + dashSize;
if(topY > y2) {
topY = y2;
}
int firstY = y;
if(firstY < y1) {
firstY = y1;
}
if(firstY < topY) {
g.drawLine(x1, firstY, x1, topY);
}
}
}
else {
// Not supported
g.drawLine(x1, y1, x2, y2);
}
}
}</source>
Handling JFrame Events
The JFrame class supports the registration of eleven different listeners:
- ComponentListener: To find out when the frame moves or is resized.
- ContainerListener: Normally not added to a JFrame because you add components to the content pane of its JRootPane.
- FocusListener: To find out when the frame gets or loses input focus.
- HierarchyBoundsListener: To find out when the frame moves or is resized.
- HierarchyListener: To find out when the frame is shown or hidden.
- InputMethodListener: To work with input methods for internationalization.
- MouseListener and MouseMotionListener: To listen for mouse and mouse motion events.
- PropertyChangeListener: To listen for changes to bound properties.
- WindowListener: To find out when a window is iconified, deiconified, closing, closed and so on.
- KeyListener: Normally not added to a JFrame. Instead, you register a keyboard action for its content pane, like this:
<source lang="java">
JPanel content = (JPanel)frame.getContentPane();
KeyStroke stroke = KeyStroke.getKeyStroke(KeyEvent.VK_ESCAPE, 0);
content.registerKeyboardAction(actionListener, stroke, JComponent.WHEN_IN_FOCUSED_WINDOW);</source>
JFrame with Label and Window Listener to Handle Closing the Frame
<source lang="java">
import java.awt.event.WindowAdapter; import java.awt.event.WindowEvent; import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.WindowConstants; class WindowEventHandler extends WindowAdapter {
public void windowClosing(WindowEvent evt) {
System.exit(0);
}
} public class TJFrame {
public static void main(String[] args) {
JFrame frame = new JFrame("Swing Frame");
JLabel label = new JLabel("This is a Swing frame", JLabel.CENTER);
frame.add(label);
frame.addWindowListener(new WindowEventHandler());
frame.setDefaultCloseOperation(WindowConstants.DISPOSE_ON_CLOSE);
frame.setSize(350, 200); // width=350, height=200
frame.setVisible(true); // Display the frame
}
}</source>
Make a JFrame always visible
<source lang="java">
import javax.swing.JFrame; import javax.swing.JLabel; public class Main{
public static void main(String[] args) {
JFrame frame = new JFrame("Hello!!");
frame.setAlwaysOnTop(true);
frame.setLocationByPlatform(true);
frame.add(new JLabel(" Always visible"));
frame.pack();
frame.setVisible(true);
}
}</source>
Make a JInternalFrame a tool window
<source lang="java">
/*
* Copyright (C) 2001-2004 Colin Bell * colbell@users.sourceforge.net * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
import java.awt.ruponent; import java.awt.Container; import java.awt.Dimension; import java.awt.FontMetrics; import java.awt.Frame; import java.awt.GraphicsConfiguration; import java.awt.GraphicsDevice; import java.awt.GraphicsEnvironment; import java.awt.Insets; import java.awt.Point; import java.awt.Rectangle; import java.awt.Toolkit; import java.awt.Window; import java.awt.geom.Rectangle2D; import java.beans.PropertyVetoException; import java.util.ArrayList; import java.util.Iterator; import java.util.List; import javax.swing.JButton; import javax.swing.JFrame; import javax.swing.JInternalFrame; import javax.swing.SwingUtilities; /**
* Common GUI utilities accessed via static methods. * * @author */
public class GUIUtils {
/**
* Return true if frame is a tool window. I.E. is the
* JInternalFrame.isPalette set to Boolean.TRUE?
*
* @param frame
* The JInternalFrame to be checked.
*
* @throws IllegalArgumentException
* If frame is null.
*/
public static boolean isToolWindow(JInternalFrame frame) {
if (frame == null) {
throw new IllegalArgumentException("null JInternalFrame passed");
}
final Object obj = frame.getClientProperty("JInternalFrame.isPalette");
return obj != null && obj == Boolean.TRUE;
}
/**
* Make the passed internal frame a Tool Window.
*/
public static void makeToolWindow(JInternalFrame frame, boolean isToolWindow) {
if (frame == null) {
throw new IllegalArgumentException("null JInternalFrame passed");
}
frame
.putClientProperty("JInternalFrame.isPalette", isToolWindow ? Boolean.TRUE : Boolean.FALSE);
}
}</source>
Making a Frame Non-Resizable: use setResizable(false) to freeze a frame"s size.
<source lang="java">
import java.awt.Frame; public class Main {
public static void main() {
Frame frame = new Frame();
frame.setResizable(false);
boolean resizable = frame.isResizable();
}
}</source>
Maximize a JFrame
<source lang="java">
import java.awt.GraphicsEnvironment; import javax.swing.JFrame; public class Main extends JFrame {
public Main() {
GraphicsEnvironment env = GraphicsEnvironment.getLocalGraphicsEnvironment();
this.setExtendedState(this.getExtendedState() | this.MAXIMIZED_BOTH);
}
public static void main(String[] args) {
JFrame.setDefaultLookAndFeelDecorated(true);
Main t = new Main();
t.setVisible(true);
}
}</source>
Move JInternalFrame To Front
<source lang="java">
/*
* Copyright (C) 2001-2004 Colin Bell * colbell@users.sourceforge.net * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
import java.awt.ruponent; import java.awt.Container; import java.awt.Dimension; import java.awt.FontMetrics; import java.awt.Frame; import java.awt.GraphicsConfiguration; import java.awt.GraphicsDevice; import java.awt.GraphicsEnvironment; import java.awt.Insets; import java.awt.Point; import java.awt.Rectangle; import java.awt.Toolkit; import java.awt.Window; import java.awt.geom.Rectangle2D; import java.beans.PropertyVetoException; import java.util.ArrayList; import java.util.Iterator; import java.util.List; import javax.swing.JButton; import javax.swing.JFrame; import javax.swing.JInternalFrame; import javax.swing.SwingUtilities; /**
* Common GUI utilities accessed via static methods. * * @author */
public class GUIUtils {
public static void moveToFront(final JInternalFrame fr) {
if (fr != null) {
processOnSwingEventThread(new Runnable() {
public void run() {
fr.moveToFront();
fr.setVisible(true);
try {
fr.setSelected(true);
if (fr.isIcon()) {
fr.setIcon(false);
}
fr.setSelected(true);
} catch (PropertyVetoException ex) {
}
fr.requestFocus();
}
});
}
}
public static void processOnSwingEventThread(Runnable todo) {
processOnSwingEventThread(todo, false);
}
public static void processOnSwingEventThread(Runnable todo, boolean wait) {
if (todo == null) {
throw new IllegalArgumentException("Runnable == null");
}
if (wait) {
if (SwingUtilities.isEventDispatchThread()) {
todo.run();
} else {
try {
SwingUtilities.invokeAndWait(todo);
} catch (Exception ex) {
throw new RuntimeException(ex);
}
}
} else {
if (SwingUtilities.isEventDispatchThread()) {
todo.run();
} else {
SwingUtilities.invokeLater(todo);
}
}
}
}</source>
Preventing a Window from Gaining the Focus
<source lang="java">
import javax.swing.JFrame; public class Main {
public static void main(String[] argv) throws Exception {
JFrame frame = new JFrame();
frame.setFocusableWindowState(false);
}
}</source>
Removing the Title Bar of a Frame
<source lang="java">
import java.awt.Frame; public class Main {
public static void main() {
Frame frame = new Frame();
frame.setUndecorated(true);
// Get the current decorated state
boolean undecorated = frame.isUndecorated();
}
}</source>
Resizing and positioning a JFrame
The pack method resizes a JFrame to a default width and height. To resize a JFrame, call the setSize method
<source lang="java">
public void setSize (int width, int height) public void setSize (java.awt.Dimension d)</source>
Set Default window close operation
<source lang="java">
import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import javax.swing.JButton; import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.JOptionPane; import javax.swing.JPanel; import javax.swing.JTextField; public class MainClass extends JFrame {
private JButton buttonOK = new JButton("OK");
private JTextField textName = new JTextField(15);
public static void main(String[] args) {
new MainClass();
}
public MainClass() {
this.setSize(325, 100);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
ButtonListener bl = new ButtonListener();
JPanel panel1 = new JPanel();
panel1.add(new JLabel("Enter your name: "));
panel1.add(textName);
buttonOK.addActionListener(bl);
panel1.add(buttonOK);
this.add(panel1);
this.setVisible(true);
}
private class ButtonListener implements ActionListener {
public void actionPerformed(ActionEvent e) {
if (e.getSource() == buttonOK) {
String name = textName.getText();
if (name.length() == 0) {
JOptionPane.showMessageDialog(MainClass.this, "=0", "", JOptionPane.INFORMATION_MESSAGE);
} else {
JOptionPane.showMessageDialog(MainClass.this, "Good morning " + name, "Salutations",
JOptionPane.INFORMATION_MESSAGE);
}
textName.requestFocus();
}
}
}
}</source>
SetIconImages for JFrame
<source lang="java">
import java.awt.Color; import java.awt.Graphics; import java.awt.image.BufferedImage; import java.util.ArrayList; import javax.swing.JDialog; import javax.swing.JFrame; public class WindowIcons extends JFrame {
final static int BIG_ICON_RENDER_WIDTH = 20;
final static int SMALL_ICON_WIDTH = 16;
final static int SMALL_ICON_HEIGHT = 16;
final static int SMALL_ICON_RENDER_WIDTH = 10;
public WindowIcons() {
setDefaultCloseOperation(EXIT_ON_CLOSE);
ArrayList<BufferedImage> images = new ArrayList<BufferedImage>();
BufferedImage bi = new BufferedImage(SMALL_ICON_WIDTH, SMALL_ICON_HEIGHT,
BufferedImage.TYPE_INT_ARGB);
Graphics g = bi.getGraphics();
g.setColor(Color.black);
g.fillRect(0, 0, SMALL_ICON_RENDER_WIDTH, SMALL_ICON_HEIGHT);
g.dispose();
images.add(bi);
setIconImages(images);
setSize(250, 100);
setVisible(true);
new JDialog(this, "Arbitrary Dialog") {
{
setSize(200, 100);
setVisible(true);
}
};
}
public static void main(String[] args) {
new WindowIcons();
}
}</source>
Setting the Icon for a Frame
<source lang="java">
import java.awt.Image; import java.awt.Toolkit; import javax.swing.JFrame; public class Main {
public static void main() {
JFrame frame = new JFrame();
Image icon = Toolkit.getDefaultToolkit().getImage("icon.gif");
frame.setIconImage(icon);
}
}</source>
Sizing Windows with Toolkit
<source lang="java">
import java.awt.Dimension; import java.awt.Toolkit; import javax.swing.JFrame; public class SizingWindowswithToolkit {
public static void main(String[] args) {
JFrame aWindow = new JFrame("This is the Window Title");
Toolkit theKit = aWindow.getToolkit();
Dimension wndSize = theKit.getScreenSize();
aWindow.setBounds(wndSize.width / 4, wndSize.height / 4, // Position
wndSize.width / 2, wndSize.height / 2); // Size
aWindow.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
aWindow.setVisible(true);
}
}</source>
Specifying Window Decorations
<source lang="java">
/*
*
* Copyright (c) 1998 Sun Microsystems, Inc. All Rights Reserved.
*
* Sun grants you ("Licensee") a non-exclusive, royalty free, license to use,
* modify and redistribute this software in source and binary code form,
* provided that i) this copyright notice and license appear on all copies of
* the software; and ii) Licensee does not utilize the software in a manner
* which is disparaging to Sun.
*
* This software is provided "AS IS," without a warranty of any kind. ALL
* EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES, INCLUDING ANY
* IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE OR
* NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN AND ITS LICENSORS SHALL NOT BE
* LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING
* OR DISTRIBUTING THE SOFTWARE OR ITS DERIVATIVES. IN NO EVENT WILL SUN OR ITS
* LICENSORS BE LIABLE FOR ANY LOST REVENUE, PROFIT OR DATA, OR FOR DIRECT,
* INDIRECT, SPECIAL, CONSEQUENTIAL, INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER
* CAUSED AND REGARDLESS OF THE THEORY OF LIABILITY, ARISING OUT OF THE USE OF
* OR INABILITY TO USE SOFTWARE, EVEN IF SUN HAS BEEN ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGES.
*
* This software is not designed or intended for use in on-line control of
* aircraft, air traffic, aircraft navigation or aircraft communications; or in
* the design, construction, operation or maintenance of any nuclear
* facility. Licensee represents and warrants that it will not use or
* redistribute the Software for such purposes.
*/
import java.awt.BorderLayout; import java.awt.Color; import java.awt.ruponent; import java.awt.Container; import java.awt.Dimension; import java.awt.Graphics; import java.awt.Image; import java.awt.Point; import java.awt.Toolkit; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.awt.event.WindowAdapter; import java.awt.image.BufferedImage; import javax.swing.BorderFactory; import javax.swing.Box; import javax.swing.BoxLayout; import javax.swing.ButtonGroup; import javax.swing.ImageIcon; import javax.swing.JButton; import javax.swing.JComponent; import javax.swing.JDialog; import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.JPanel; import javax.swing.JRadioButton; import javax.swing.UIManager; public class FrameDemo2 extends WindowAdapter implements ActionListener {
private Point lastLocation = null;
private int maxX = 500;
private int maxY = 500;
// the main frame"s default button
private static JButton defaultButton = null;
// constants for action commands
protected final static String NO_DECORATIONS = "no_dec";
protected final static String LF_DECORATIONS = "laf_dec";
protected final static String WS_DECORATIONS = "ws_dec";
protected final static String CREATE_WINDOW = "new_win";
protected final static String DEFAULT_ICON = "def_icon";
protected final static String FILE_ICON = "file_icon";
protected final static String PAINT_ICON = "paint_icon";
// true if the next frame created should have no window decorations
protected boolean noDecorations = false;
// true if the next frame created should have setIconImage called
protected boolean specifyIcon = false;
// true if the next frame created should have a custom painted icon
protected boolean createIcon = false;
// Perform some initialization.
public FrameDemo2() {
Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
maxX = screenSize.width - 50;
maxY = screenSize.height - 50;
}
// Create a new MyFrame object and show it.
public void showNewWindow() {
JFrame frame = new MyFrame();
// Take care of the no window decorations case.
// NOTE: Unless you really need the functionality
// provided by JFrame, you would usually use a
// Window or JWindow instead of an undecorated JFrame.
if (noDecorations) {
frame.setUndecorated(true);
}
// Set window location.
if (lastLocation != null) {
// Move the window over and down 40 pixels.
lastLocation.translate(40, 40);
if ((lastLocation.x > maxX) || (lastLocation.y > maxY)) {
lastLocation.setLocation(0, 0);
}
frame.setLocation(lastLocation);
} else {
lastLocation = frame.getLocation();
}
// Calling setIconImage sets the icon displayed when the window
// is minimized. Most window systems (or look and feels, if
// decorations are provided by the look and feel) also use this
// icon in the window decorations.
if (specifyIcon) {
if (createIcon) {
frame.setIconImage(createFDImage()); // create an icon from scratch
} else {
frame.setIconImage(getFDImage()); // get the icon from a file
}
}
// Show window.
frame.setSize(new Dimension(170, 100));
frame.setVisible(true);
}
// Create the window-creation controls that go in the main window.
protected JComponent createOptionControls() {
JLabel label1 = new JLabel("Decoration options for subsequently created frames:");
ButtonGroup bg1 = new ButtonGroup();
JLabel label2 = new JLabel("Icon options:");
ButtonGroup bg2 = new ButtonGroup();
// Create the buttons
JRadioButton rb1 = new JRadioButton();
rb1.setText("Look and feel decorated");
rb1.setActionCommand(LF_DECORATIONS);
rb1.addActionListener(this);
rb1.setSelected(true);
bg1.add(rb1);
//
JRadioButton rb2 = new JRadioButton();
rb2.setText("Window system decorated");
rb2.setActionCommand(WS_DECORATIONS);
rb2.addActionListener(this);
bg1.add(rb2);
//
JRadioButton rb3 = new JRadioButton();
rb3.setText("No decorations");
rb3.setActionCommand(NO_DECORATIONS);
rb3.addActionListener(this);
bg1.add(rb3);
//
//
JRadioButton rb4 = new JRadioButton();
rb4.setText("Default icon");
rb4.setActionCommand(DEFAULT_ICON);
rb4.addActionListener(this);
rb4.setSelected(true);
bg2.add(rb4);
//
JRadioButton rb5 = new JRadioButton();
rb5.setText("Icon from a JPEG file");
rb5.setActionCommand(FILE_ICON);
rb5.addActionListener(this);
bg2.add(rb5);
//
JRadioButton rb6 = new JRadioButton();
rb6.setText("Painted icon");
rb6.setActionCommand(PAINT_ICON);
rb6.addActionListener(this);
bg2.add(rb6);
// Add everything to a container.
Box box = Box.createVerticalBox();
box.add(label1);
box.add(Box.createVerticalStrut(5)); // spacer
box.add(rb1);
box.add(rb2);
box.add(rb3);
//
box.add(Box.createVerticalStrut(15)); // spacer
box.add(label2);
box.add(Box.createVerticalStrut(5)); // spacer
box.add(rb4);
box.add(rb5);
box.add(rb6);
// Add some breathing room.
box.setBorder(BorderFactory.createEmptyBorder(10, 10, 10, 10));
return box;
}
// Create the button that goes in the main window.
protected JComponent createButtonPane() {
JButton button = new JButton("New window");
button.setActionCommand(CREATE_WINDOW);
button.addActionListener(this);
defaultButton = button; // Used later to make this the frame"s default
// button.
// Center the button in a panel with some space around it.
JPanel pane = new JPanel(); // use default FlowLayout
pane.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
pane.add(button);
return pane;
}
// Handle action events from all the buttons.
public void actionPerformed(ActionEvent e) {
String command = e.getActionCommand();
// Handle the New window button.
if (CREATE_WINDOW.equals(command)) {
showNewWindow();
// Handle the first group of radio buttons.
} else if (NO_DECORATIONS.equals(command)) {
noDecorations = true;
JFrame.setDefaultLookAndFeelDecorated(false);
} else if (WS_DECORATIONS.equals(command)) {
noDecorations = false;
JFrame.setDefaultLookAndFeelDecorated(false);
} else if (LF_DECORATIONS.equals(command)) {
noDecorations = false;
JFrame.setDefaultLookAndFeelDecorated(true);
// Handle the second group of radio buttons.
} else if (DEFAULT_ICON.equals(command)) {
specifyIcon = false;
} else if (FILE_ICON.equals(command)) {
specifyIcon = true;
createIcon = false;
} else if (PAINT_ICON.equals(command)) {
specifyIcon = true;
createIcon = true;
}
}
// Creates an icon-worthy Image from scratch.
protected static Image createFDImage() {
// Create a 16x16 pixel image.
BufferedImage bi = new BufferedImage(16, 16, BufferedImage.TYPE_INT_RGB);
// Draw into it.
Graphics g = bi.getGraphics();
g.setColor(Color.BLACK);
g.fillRect(0, 0, 15, 15);
g.setColor(Color.RED);
g.fillOval(5, 3, 6, 6);
// Clean up.
g.dispose();
// Return it.
return bi;
}
// Returns an Image or null.
protected static Image getFDImage() {
java.net.URL imgURL = FrameDemo2.class.getResource("images/FD.jpg");
if (imgURL != null) {
return new ImageIcon(imgURL).getImage();
} else {
return null;
}
}
/**
* Create the GUI and show it. For thread safety, this method should be
* invoked from the event-dispatching thread.
*/
private static void createAndShowGUI() {
// Use the Java look and feel.
try {
UIManager.setLookAndFeel(UIManager.getCrossPlatformLookAndFeelClassName());
} catch (Exception e) {
}
// Make sure we have nice window decorations.
JFrame.setDefaultLookAndFeelDecorated(true);
JDialog.setDefaultLookAndFeelDecorated(true);
// Instantiate the controlling class.
JFrame frame = new JFrame("FrameDemo2");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
// Create and set up the content pane.
FrameDemo2 demo = new FrameDemo2();
// Add components to it.
Container contentPane = frame.getContentPane();
contentPane.add(demo.createOptionControls(), BorderLayout.CENTER);
contentPane.add(demo.createButtonPane(), BorderLayout.PAGE_END);
frame.getRootPane().setDefaultButton(defaultButton);
// Display the window.
frame.pack();
frame.setLocationRelativeTo(null); // center it
frame.setVisible(true);
}
// Start the demo.
public static void main(String[] args) {
// Schedule a job for the event-dispatching thread:
// creating and showing this application"s GUI.
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGUI();
}
});
}
class MyFrame extends JFrame implements ActionListener {
// Create a frame with a button.
public MyFrame() {
super("A window");
setDefaultCloseOperation(DISPOSE_ON_CLOSE);
// This button lets you close even an undecorated window.
JButton button = new JButton("Close window");
button.addActionListener(this);
// Place the button near the bottom of the window.
Container contentPane = getContentPane();
contentPane.setLayout(new BoxLayout(contentPane, BoxLayout.PAGE_AXIS));
contentPane.add(Box.createVerticalGlue()); // takes all extra space
contentPane.add(button);
button.setAlignmentX(Component.CENTER_ALIGNMENT); // horizontally centered
contentPane.add(Box.createVerticalStrut(5)); // spacer
}
// Make the button do the same thing as the default close operation
// (DISPOSE_ON_CLOSE).
public void actionPerformed(ActionEvent e) {
setVisible(false);
dispose();
}
}
}</source>
Use Component listener to ensure frame visibilities
<source lang="java">
import java.awt.Dimension; import java.awt.Toolkit; import java.awt.event.ruponentAdapter; import java.awt.event.ruponentEvent; import javax.swing.JFrame; public class Main extends ComponentAdapter {
public void componentMoved(ComponentEvent evt) {
Dimension size = Toolkit.getDefaultToolkit().getScreenSize();
int x = evt.getComponent().getX();
int y = evt.getComponent().getY();
if (y < 0 ) {
y = 0;
}
if (x < 0 ) {
x = 0;
}
if (x > size.getWidth() - evt.getComponent().getWidth() ) {
x = (int) size.getWidth() - evt.getComponent().getWidth();
}
if (y > size.getHeight() - evt.getComponent().getHeight() ) {
y = (int) size.getHeight() - evt.getComponent().getHeight();
}
evt.getComponent().setLocation(x, y);
}
public static void main(String[] args) {
JFrame frame = new JFrame("Window cannot be moved to hide part of it");
frame.setSize(300,300);
frame.addComponentListener(new Main());
frame.setVisible(true);
}
}</source>
