This question already has answers here:
Sizing a JScrollPane in a JTabbedPane in a JFrame
(2 answers)
Closed 8 years ago.
I am starting this new question because this question has been voted to close since it didnt have an MVCE.
I have included the question with an SSCCE now.
Please take a look at the below code
import javax.swing.*;
import java.awt.*;
public class ScrollPaneTest {
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
JFrame frame=new JFrame();
frame.setDefaultCloseOperation(WindowConstants.DISPOSE_ON_CLOSE);
JTabbedPane tabbedPane=new JTabbedPane();
tabbedPane.addTab("Tab 1", new JScrollPane(getPanel()));
tabbedPane.addTab("Tab 2", new JScrollPane(getPanel()));
frame.setContentPane(tabbedPane);
frame.pack();
frame.setVisible(true);
}
private JPanel getPanel() {
JPanel panel=new JPanel();
Box box = Box.createVerticalBox();
for (int i = 1; i <= 100; i++) {
box.add(new JLabel("This is Label #" + i));
}
panel.add(box);
return panel;
}
});
}
}
When I run this code I get a frame shown as below
In the same code if I add a
frame.setExtendedState(JFrame.MAXIMIZED_BOTH);
Then the frame comes above the task bar. I would like my JFrame to stop just above the taskbar of windows.
This is basically a little hacky.
What this does is uses the screen bounds minus it's insets to calculate not only the height of the window, but also the position to encourage the window to appear within the available desktop space.
The main reason for this, is I have my taskbar pinned to the top of my screen...
import java.awt.GraphicsConfiguration;
import java.awt.GraphicsDevice;
import java.awt.GraphicsEnvironment;
import java.awt.Insets;
import java.awt.Rectangle;
import java.awt.Toolkit;
import javax.swing.Box;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTabbedPane;
import javax.swing.SwingUtilities;
import javax.swing.WindowConstants;
public class ScrollPaneTest {
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(WindowConstants.DISPOSE_ON_CLOSE);
JTabbedPane tabbedPane = new JTabbedPane();
tabbedPane.addTab("Tab 1", new JScrollPane(getPanel()));
tabbedPane.addTab("Tab 2", new JScrollPane(getPanel()));
frame.setContentPane(tabbedPane);
frame.pack();
Rectangle viewBounds = getScreenViewableBounds();
frame.setSize(frame.getWidth(), viewBounds.height);
frame.setLocation(viewBounds.x, viewBounds.y);
frame.setVisible(true);
}
private JPanel getPanel() {
JPanel panel = new JPanel();
Box box = Box.createVerticalBox();
for (int i = 1; i <= 100; i++) {
box.add(new JLabel("This is Label #" + i));
}
panel.add(box);
return panel;
}
});
}
public static Rectangle getScreenViewableBounds() {
GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment();
GraphicsDevice gd = ge.getDefaultScreenDevice();
Rectangle bounds = new Rectangle(0, 0, 0, 0);
if (gd != null) {
GraphicsConfiguration gc = gd.getDefaultConfiguration();
bounds = gc.getBounds();
Insets insets = Toolkit.getDefaultToolkit().getScreenInsets(gc);
bounds.x += insets.left;
bounds.y += insets.top;
bounds.width -= (insets.left + insets.right);
bounds.height -= (insets.top + insets.bottom);
}
return bounds;
}
}
You may also wish to consider using the Scrollable interface to restrict the viewable area, for example...
import java.awt.Dimension;
import java.awt.GraphicsConfiguration;
import java.awt.GraphicsDevice;
import java.awt.GraphicsEnvironment;
import java.awt.Insets;
import java.awt.Rectangle;
import java.awt.Toolkit;
import javax.swing.Box;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTabbedPane;
import javax.swing.Scrollable;
import javax.swing.SwingUtilities;
import javax.swing.WindowConstants;
public class ScrollPaneTest {
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(WindowConstants.DISPOSE_ON_CLOSE);
JTabbedPane tabbedPane = new JTabbedPane();
tabbedPane.addTab("Tab 1", new JScrollPane(getPanel()));
tabbedPane.addTab("Tab 2", new JScrollPane(getPanel()));
frame.setContentPane(tabbedPane);
frame.pack();
frame.setVisible(true);
}
private JPanel getPanel() {
JPanel panel = new ScrollablePane();
Box box = Box.createVerticalBox();
for (int i = 1; i <= 100; i++) {
box.add(new JLabel("This is Label #" + i));
}
panel.add(box);
return panel;
}
});
}
public static class ScrollablePane extends JPanel implements Scrollable {
#Override
public Dimension getPreferredScrollableViewportSize() {
return new Dimension(200, 400);
}
#Override
public int getScrollableUnitIncrement(Rectangle visibleRect, int orientation, int direction) {
return 32;
}
#Override
public int getScrollableBlockIncrement(Rectangle visibleRect, int orientation, int direction) {
return 32;
}
#Override
public boolean getScrollableTracksViewportWidth() {
return false;
}
#Override
public boolean getScrollableTracksViewportHeight() {
return false;
}
}
}
Related
I need to calculate window decorations somehow. So I override JDialog's constructor. But when I call get_decoration_size() it sometimes returns wrong values. And my thought was: window creates later than get_decoration_size() executes(strange, because both in same thread and in same constructor). So I decided to sleep for a second, and it worked, and now decorations always valid.
My question is: is there a way to "join" to the creating process(wait until window is shown by setVisible(true))? If so, it must be something to replace unsafe_sleep(1000).
package swing.window;
import db.db;
import javax.swing.*;
import java.awt.*;
import static swing.util.*;
import static util.util.unsafe_sleep;
public class calc_decor extends JDialog {
{
//some initializations
setLayout(null);
setResizable(false);
JLabel label = new JLabel("Loading...");
add(label);
setxy(label, 3, 3);
fit(label);
setsize(this, label.getWidth() + 100, label.getHeight() + 100);
window_to_center(this);
setVisible(true);//trying to draw
unsafe_sleep(1000);//without that it looks like get_decoratoin_size()
//is called before setVisible(true)
db.sysdecor = get_decoration_size();//trying to get decorations
dispose();
}
private Dimension get_decoration_size() {
Rectangle window = getBounds();
Rectangle content = getContentPane().getBounds();
int width = window.width - content.width;
int height = window.height - content.height;
return new Dimension(width, height);
}
}
I had to assume a lot to create a runnable example.
Here's the result of your getDecorationSize method. The line didn't print until I closed the JDialog.
java.awt.Dimension[width=16,height=39]
And here's the code I used.
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.Rectangle;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JDialog;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class JDialogTest implements Runnable {
public static void main(String[] args) {
SwingUtilities.invokeLater(new JDialogTest());
}
private JFrame frame;
#Override
public void run() {
frame = new JFrame("JDialog Test");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(createMainPanel());
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
private JPanel createMainPanel() {
JPanel panel = new JPanel(new BorderLayout());
panel.setBorder(BorderFactory.createEmptyBorder(
150, 100, 150, 100));
panel.setPreferredSize(new Dimension(400, 400));
JButton button = new JButton("Open JDialog");
button.addActionListener(new ButtonListener());
panel.add(button);
return panel;
}
public class ButtonListener implements ActionListener {
#Override
public void actionPerformed(ActionEvent e) {
new CalculateDecor(frame, "Spash Screen");
}
}
public class CalculateDecor extends JDialog {
private static final long serialVersionUID = 1L;
public CalculateDecor(JFrame frame, String title) {
super(frame, true);
setDefaultCloseOperation(DISPOSE_ON_CLOSE);
setTitle(title);
JPanel panel = new JPanel(new BorderLayout());
panel.setPreferredSize(new Dimension(200, 200));
JLabel label = new JLabel("Loading...");
label.setHorizontalAlignment(JLabel.CENTER);
panel.add(label);
add(panel);
pack();
setLocationRelativeTo(frame);
setVisible(true);
System.out.println(getDecorationSize());
}
private Dimension getDecorationSize() {
Rectangle window = getBounds();
Rectangle content = getContentPane().getBounds();
int width = window.width - content.width;
int height = window.height - content.height;
return new Dimension(width, height);
}
}
}
The intention of my code is to create a rectangle when the button is clicked. The button works fine but the rectangle itself is not showing up on the screen, and there are no errors. Thank you for helping btw.
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Rectangle;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Random;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class Tester {
static JButton button;
static JFrame frame;
static JPanel panel;
static Rectangle rec;
static void init(){
button = new JButton();
frame = new JFrame();
panel = new JPanel();
rec = new Rectangle(30,30,30,30);
button.setVisible(true);
panel.add(button);
frame.add(panel);
frame.setVisible(true);
panel.setVisible(true);
frame.setSize(200, 200);
button.setBackground(Color.GREEN);
button.setBounds(30, 30, 20, 20);
}
public static void main(String[] args) {
init();
ActionListener listener = new RectangleMover();
button.addActionListener(listener);
}
static class RectangleMover implements ActionListener{
#Override
public void actionPerformed(ActionEvent arg0) {
RectanglePainter r = new RectanglePainter();
r.add(rec);
}
}
static class RectanglePainter extends JPanel{
void add(Rectangle r){
rec = r;
repaint();
}
protected void paintComponent(Graphics g){
Graphics2D g2 = (Graphics2D) g;
Random r = new Random();
int i =r.nextInt(2);
if (i==1)
g2.setColor(Color.BLUE);
else
g2.setColor(Color.RED);
g2.fill(rec);
g2.draw(rec);
}
}
}
Your generally approach is slightly skewed, rather than using another JComponent to "act" as the shape, you should be using it to paint all the shapes through it's paintComponent method
From my "red rectangle" period...
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Rectangle;
import java.awt.Shape;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.ArrayList;
import java.util.List;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class Tester {
public static void main(String[] args) {
new Tester();
}
public Tester() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
ex.printStackTrace();
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class TestPane extends JPanel {
private JPanel panel;
private JButton button;
private JLabel label;
private ShapePane shapePane;
public TestPane() {
setLayout(new BorderLayout());
button = new JButton("Rectangle");
panel = new JPanel();
label = new JLabel();
button.setVisible(true);
panel.add(button);
panel.add(label);
shapePane = new ShapePane();
add(shapePane);
add(panel, BorderLayout.SOUTH);
class ClickListener implements ActionListener {
private int X = 20;
private int Y = 20;
#Override
public void actionPerformed(ActionEvent arg0) {
int width = shapePane.getWidth();
int height = shapePane.getHeight();
int x = (int)(Math.random() * (width - 20)) + 10;
int y = (int)(Math.random() * (height - 20)) + 10;
int w = (int)(Math.random() * (width - x));
int h = (int)(Math.random() * (height - y));
shapePane.add(new Rectangle(x, y, w, h));
}
}
ActionListener listener = new ClickListener();
button.addActionListener(listener);
}
}
public class ShapePane extends JPanel {
private List<Shape> shapes;
public ShapePane() {
shapes = new ArrayList<>(25);
}
#Override
public Dimension getPreferredSize() {
return new Dimension(200, 200);
}
public void add(Rectangle rectangle) {
shapes.add(rectangle);
repaint();
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2 = (Graphics2D) g;
g2.setColor(Color.RED);
for (Shape shape : shapes) {
g2.draw(shape);
}
}
}
}
As to answer your basic question, you could have tried calling revalidate and repaint, but because of the BorderLayout I doubt it would have worked as you would have basically been trying to replace the panel with your ShapeChanger component, and there are better ways to do that
I've been hunting through past StackOverflow posts and trying to figure out why my image won't display.
I know that the ImageIO is fine since I can run getWidth() on my BufferedImage and it returns the correct width.
Here is my Graphic class, followed by my main class.
(I'm sorry for trashy code, I'm new to this.)
Code in Graphic class:
package blackjack;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
public class Graphic extends JPanel implements ActionListener {
/**
*
*/
private static final long serialVersionUID = 1L;
public JFrame frame = new JFrame("Game Window");
public JPanel layout = new JPanel(new BorderLayout());
public JPanel menu = new JPanel();
public JPanel playing = new JPanel(new BorderLayout());
public JPanel game = new JPanel();
public BufferedImage cardArray[] = new BufferedImage[52];
public void begin() {
//starting menu
}
public void playersTurn() {
menu.add(playing);
Font font = new Font("",Font.PLAIN, 24);
JPanel btnHolder = new JPanel();
JLabel play = new JLabel("Playing:");
JLabel or = new JLabel(" or ");
JLabel question = new JLabel(" ? ");
question.setFont(font);
or.setFont(font);
play.setFont(font);
JButton hit = new JButton("Hit");
JButton stand = new JButton("Stand");
hit.addActionListener(this);
stand.addActionListener(this);
playing.add(play, BorderLayout.WEST);
playing.add(btnHolder, BorderLayout.CENTER);
btnHolder.add(hit);
btnHolder.add(or);
btnHolder.add(stand);
btnHolder.add(question);
}
public void gui() {
//main gui
Dimension imageD = new Dimension(71,96);
Dimension menuD = new Dimension(900,120);
menu.setBorder(BorderFactory.createLineBorder(Color.black));
menu.setPreferredSize(menuD);
JPanel titlePanel = new JPanel();
JLabel title = new JLabel("BlackJack");
title.setFont(new Font("", Font.PLAIN, 14));
titlePanel.add(title);
Graphic gr = new Graphic();
gr.setPreferredSize(imageD);
//adding
frame.add(layout);
layout.add(menu, BorderLayout.SOUTH);
layout.add(titlePanel, BorderLayout.NORTH);
layout.add(gr, BorderLayout.CENTER);
//frame settings
frame.setSize(900, 650);
frame.setResizable(false);
frame.setVisible(true);
}
public void buildPathArray() {
for(int i = 1; i<=52; i++){
BufferedImage im = null;
try {
im = ImageIO.read(new File(Blackjack.getInstallDir() + Blackjack.s + "src" + Blackjack.s + "cardpngs"+ Blackjack.s + (100+i)+".png"));
} catch (IOException e) {
e.printStackTrace();
}
cardArray[i-1]= im;
//System.out.println(Blackjack.getInstallDir() + "\\src\\cardpngs\\" + (100+i)+".png");
}
}
#Override
public void actionPerformed(ActionEvent e) {
if(e.getActionCommand().equals("Hit")) {
} else if(e.getActionCommand().equals("Stand")) {
}
}
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
//g.setColor(Color.GREEN);
//g.fillOval(20, 20, 20, 20);
g.drawImage(cardArray[0], 0, 0, this);
}
}
Code in my main class:
package blackjack;
import java.nio.file.Path;
import java.nio.file.Paths;
public class Blackjack {
public static String installDir = "";
public static String s = "";
public static void main(String[] args) {
Path currentRelativePath = Paths.get("");
installDir = currentRelativePath.toAbsolutePath().toString();
s = System.getProperty("file.separator");
Graphic gr = new Graphic();
gr.buildPathArray();
gr.gui();
//System.out.println(installDir);
//g.playersTurn();
}
public static String getInstallDir() {
return installDir;
}
}
The output is this:
You're creating one instance of Graphic in your Blackjack class...
public class Blackjack {
public static String installDir = "";
public static String s = "";
public static void main(String[] args) {
//...
Graphic gr = new Graphic();
gr.buildPathArray();
gr.gui();
}
And another in your Graphic class
public void gui() {
//...
Graphic gr = new Graphic();
gr.setPreferredSize(imageD);
//adding
//...
layout.add(gr, BorderLayout.CENTER);
//...
}
But you only initialise the images, using buildPathArray of the instance in you BlackBelt class, which is not what is actually displayed on the screen...
As a general rule of thumb, you shouldn't be creating an instance of JFrame from within another component with the express purpose of display that component. Your Graphic component is also trying to do too much. Instead, I would have a Game class, maybe, which pulled the title, menu and Graphic components together and then put that onto an instance of JFrame
The main reason for this is, is your Graphic class is trying to do too much. It should be solely responsible for display the cards and managing them. The Game class should manage the other UI elements and be responsible for ensuring that the UI meets the current state of the game "model", taking in user input (and listening to events from the other UI elements) and updating the model and responding to events that the model creates, a little more like...
BlackJack...
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Font;
import javax.swing.BorderFactory;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class BlackJack {
public static void main(String[] args) {
new BlackJack();
}
public BlackJack() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
ex.printStackTrace();
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new Game());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class Game extends JPanel {
private JPanel menu;
private Graphic graphic;
public Game() {
menu = new JPanel() {
#Override
public Dimension getPreferredSize() {
return new Dimension(900, 120);
}
};
menu.setBorder(BorderFactory.createLineBorder(Color.black));
JPanel titlePanel = new JPanel();
JLabel title = new JLabel("BlackJack");
title.setFont(new Font("", Font.PLAIN, 14));
titlePanel.add(title);
Graphic gr = new Graphic();
gr.buildPathArray();
setLayout(new BorderLayout());
add(menu, BorderLayout.SOUTH);
add(titlePanel, BorderLayout.NORTH);
add(gr, BorderLayout.CENTER);
}
}
}
Graphic...
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
public class Graphic extends JPanel {
private static final long serialVersionUID = 1L;
public BufferedImage cardArray[] = new BufferedImage[52];
public void begin() {
//starting menu
}
public void playersTurn() {
// All of this belongs in Game
}
#Override
public Dimension getPreferredSize() {
return new Dimension(71,96);
}
public void buildPathArray() {
for (int i = 1; i <= 52; i++) {
BufferedImage im = null;
try {
im = ImageIO.read(new File(Blackjack.getInstallDir() + Blackjack.s + "src" + Blackjack.s + "cardpngs" + Blackjack.s + (100 + i) + ".png"));
} catch (IOException e) {
e.printStackTrace();
}
cardArray[i - 1] = im;
//System.out.println(Blackjack.getInstallDir() + "\\src\\cardpngs\\" + (100+i)+".png");
}
}
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
//g.setColor(Color.GREEN);
//g.fillOval(20, 20, 20, 20);
g.drawImage(cardArray[0], 0, 0, this);
}
}
You might also want to have a look at Model-View-Controller.
JTabbedPane - tab border is being shown even after using BasicTabbedPaneUI. Please let me know how can I change such that no border is shown between the tabs? Is there any method to remove the border completely ?
Please Send me the code snippet. Thanks in advance.
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import javax.swing.BorderFactory;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTabbedPane;
import javax.swing.SwingUtilities;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;
import javax.swing.plaf.basic.BasicTabbedPaneUI;
public class TabbedPaneTest implements Runnable {
#Override
public void run() {
final JTabbedPane pane = new JTabbedPane();
pane.addTab("A", createTab(Color.RED));
pane.addTab("B", createTab(Color.YELLOW));
pane.addTab("C", createTab(Color.BLUE));
pane.setUI(new BasicTabbedPaneUI() {
#Override
protected void paintContentBorder(Graphics g, int tabPlacement, int selectedIndex) {
}
});
pane.setBackground(Color.WHITE);
pane.addChangeListener(new ChangeListener() {
#Override
public void stateChanged(ChangeEvent arg0) {
pane.setForegroundAt(pane.getSelectedIndex(), Color.GREEN);
}
});
final JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(pane);
frame.pack();
//frame.setSize(500, 200);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
private JPanel createTab(Color color) {
JPanel p = new JPanel(new BorderLayout()) {
private static final long serialVersionUID = 1L;
#Override
public Dimension getPreferredSize() {
return new Dimension(400, 300);
}
};
p.setBorder(BorderFactory.createLineBorder(color, 2));
p.setBackground(Color.WHITE);
return p;
}
public static void main(String[] args) throws Exception {
SwingUtilities.invokeLater(new TabbedPaneTest());
}
}
// Remove the white line under a tab button
Insets insets = UIManager.getInsets("TabbedPane.contentBorderInsets");
insets.top = -1;
UIManager.put("TabbedPane.contentBorderInsets", insets);
In a linux text editor, Kate, there is this nice functionality that when I click and drag the scroll bar it shows the current line numbers that are currently in view in the text component.
My question is how can I add this function in Java to my scroll pane containing a JTextArea. Which component can I use to show this notification?
Apparently you can do this with a JPopupMenu:
I tried with this class because I knew it had the method show(Component, x, y). But it might be possible with other classes, or trying to implement whatever that method does yourself.
I put a couple of mouse listeners to the scrollBar and toyed a little with the values x, y in the show() call until I was satisfied with the position where it was being drawn at.
Full code:
import java.awt.Dimension;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionAdapter;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPopupMenu;
import javax.swing.JScrollBar;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.SwingUtilities;
public class ScrollbarTest
{
private JScrollPane scrollPane;
private JScrollBar scrollBar;
private JPopupMenu popupMenu;
private JLabel popupLabel;
public static void main(String[] args)
{
SwingUtilities.invokeLater(new Runnable() {
public void run()
{
new ScrollbarTest();
}
});
}
public ScrollbarTest()
{
JFrame frame = new JFrame("Test");
popupMenu = new JPopupMenu();
popupLabel = new JLabel();
popupMenu.add(popupLabel);
scrollPane = new JScrollPane(buildTestTextArea());
scrollBar = scrollPane.getVerticalScrollBar();
scrollBar.addMouseMotionListener(new PopUpMouseMotionListener());
scrollBar.addMouseListener(new PopUpMouseListener());
frame.add(scrollPane);
frame.setSize(new Dimension(400, 400));
frame.setLocationRelativeTo(null);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
public JTextArea buildTestTextArea()
{
JTextArea textArea = new JTextArea();
StringBuilder builder = new StringBuilder();
for (int i = 0; i < 10000; ++i)
{
builder.append("X");
}
textArea.setText(builder.toString());
textArea.setLineWrap(true);
return textArea;
}
private class PopUpMouseMotionListener extends MouseMotionAdapter
{
#Override
public void mouseDragged(MouseEvent e)
{
double value = scrollBar.getValue();
double max = scrollBar.getMaximum() - scrollBar.getVisibleAmount();
double h = scrollBar.getHeight();
popupLabel.setText("" + (int) (100*value/max) + "%");
popupMenu.show(scrollPane, scrollBar.getX() - popupMenu.getWidth() - 2, (int) ((h - popupMenu.getHeight())*value/max));
}
}
private class PopUpMouseListener extends MouseAdapter
{
#Override
public void mouseReleased(MouseEvent e)
{
popupMenu.setVisible(false);
}
}
}