I have JScrollPane that contains some images in a horizontal row. If the row of images is too long for the view port, the JScrollPane shows a scroll bar, reducing the height of the view port. I'd like to resize the images to fit the view port. How can I detect that the view port changed its size? Unfortunately, registering change event handlers doesn't seem to work.
Using change listener on the ViewPort seems to work for me. Here is a small demo of that:
import java.awt.BorderLayout;
import java.io.UnsupportedEncodingException;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.SwingWorker;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;
public class Main {
public static void main(String[] args) throws UnsupportedEncodingException {
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel panel = new JPanel(new BorderLayout());
final JPanel buttons = new JPanel();
final JScrollPane pane = new JScrollPane(buttons);
pane.getViewport().addChangeListener(new ChangeListener() {
#Override
public void stateChanged(ChangeEvent e) {
System.err.println("Change in " + e.getSource());
System.err.println("Vertical visible? " + pane.getVerticalScrollBar().isVisible());
System.err.println("Horizontal visible? " + pane.getHorizontalScrollBar().isVisible());
}
});
panel.add(pane);
frame.setContentPane(panel);
frame.setSize(300, 200);
frame.setVisible(true);
SwingWorker<Void, Void> worker = new SwingWorker<Void, Void>() {
#Override
protected Void doInBackground() throws Exception {
for (int i = 0; i < 10; i++) {
Thread.sleep(800);
buttons.add(new JButton("Hello " + i));
buttons.revalidate();
}
return null;
}
};
worker.execute();
}
}
I used the HierarchyBoundsListener to detect changes in the JScrollPane's size:
onAncestorResized(scroll, evt -> resizeYourImages());
Here's a convenience method for attaching the listener:
static void onAncestorResized(JComponent component, Consumer<HierarchyEvent> callback) {
component.addHierarchyBoundsListener(new HierarchyBoundsAdapter() {
#Override
public void ancestorResized(HierarchyEvent e) {
callback.accept(e);
}
});
}
Related
i want to iconify my internal frame to an adjacent panel of the main frame than the default left bottom corner of the main frame.
i am using a jdesktopframe and inside it internal frames.
i want to iconify the connection detail which is an interal frame the iconified icon should be present where the minimize button is and should not be at the left bottom of the main frame.
this is a sample code:
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.GridLayout;
import java.awt.HeadlessException;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.beans.PropertyVetoException;
import javax.swing.JButton;
import javax.swing.JDesktopPane;
import javax.swing.JFrame;
import javax.swing.JInternalFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.plaf.basic.BasicInternalFrameTitlePane;
import javax.swing.plaf.basic.BasicInternalFrameUI;
public class MinPanel {
public MinPanel() throws HeadlessException, PropertyVetoException {
createAndShowGUI();
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
try {
new MinPanel();
} catch (HeadlessException ex) {
} catch (PropertyVetoException ex) {
}
}
});
}
private void createAndShowGUI() throws HeadlessException, PropertyVetoException {
JFrame frame = new JFrame();
frame.setResizable(true);
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
final JDesktopPane jdp = new JDesktopPane() {
#Override
public Dimension getPreferredSize() {
return new Dimension(400, 200);
}
};
frame.setContentPane(jdp);
frame.pack();
createAndAddInternalFrame(jdp, 0, 0);
createAndAddfixedpanel(jdp,200,0);
frame.setVisible(true);
}
private void createAndAddInternalFrame(final JDesktopPane jdp, int x, int y) throws PropertyVetoException {
final JInternalFrame jInternalFrame = new JInternalFrame("Test1", false, false, false, false);
jInternalFrame.setLocation(x, y);
jInternalFrame.setLayout(new GridLayout(2, 2));
jInternalFrame.setSize(200, 200);//testing
JButton jb = new JButton("min");
jInternalFrame.add(jb);
jb.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent ae) {
try {
jInternalFrame.setIcon(true);
} catch (PropertyVetoException ex) {
}
}
});
BasicInternalFrameTitlePane titlePane = (BasicInternalFrameTitlePane) ((BasicInternalFrameUI) jInternalFrame.getUI()).getNorthPane();
jInternalFrame.remove(titlePane);
jInternalFrame.setVisible(true);
jdp.add(jInternalFrame);
}
private void createAndAddfixedpanel(final JDesktopPane jdp, int x, int y)
{ JPanel panel = new JPanel();
panel.setLocation(x, y);
panel.setLayout(new FlowLayout());
panel.setSize(200, 200);
JLabel label = new JLabel("JFrame By Example");
JButton button = new JButton();
button.setText("Button");
panel.add(label);
panel.add(button);
panel.setVisible(true);
jdp.add(panel);
}
}
I would also like to resize the main frame when the internal frame is minimizes and maximized
The trick is that you don't do the setLocation() or setBounds() stuff on the JInternalFrame object. This would move the pane, which is not be visible anymore when you "iconified" the internal frame. But instead you change the Icon which is now visible when you "iconified" the internal frame. To get the icon you use the getDesktopIcon() method on the JInternalFrame class. After that it's a simple call to the setLocation() call on the received JInternalFrame.JDesktopIcon object. You can use it like this:
frame.addInternalFrameListener(new InternalFrameAdapter() {
#Override
public void internalFrameIconified(InternalFrameEvent e) {
frame.getDesktopIcon().setLocation(frame.getLocation().x, frame.getLocation().y);
}
});
Obviously you have to calculate the correct position for yourself, where you want to have the icon positioned. This example only shows how to move the icon to the correct position, so it doesn't get opened in the bottom left corner.
You might want to add a similar event handler for the opposite internalFrameDeiconified event to open the original JInternalFrame panel where the icon is, not where the panel was before it was "iconified".
basically I'm trying to understand Threads in Java.So I thought I'd create a main JFrame class containing two JPanels from external classes and then do something in one and control it with messages from the second panel.So far I have only created the first external panel and there the probleme starts! It does not show correctly although it appears to be "loaded".(see system.out lines)
So here is the Main Class
package com.maybee.gui;
import java.awt.*;
import javax.swing.*;
import javax.swing.border.LineBorder;
public class Maybee extends JFrame implements Runnable
{
public JFrame maynFrame = null;
public JPanel contentPanel = null;
public SimPanel simPanel = null;
public int screenWidth = 0;
public int screenHeight = 0;
public Maybee()
{
}
private void init()
{
System.out.println("In Inint");
maynFrame = new JFrame("Maybee");
maynFrame.setDefaultCloseOperation(DISPOSE_ON_CLOSE);
GraphicsDevice gd = GraphicsEnvironment.getLocalGraphicsEnvironment().getDefaultScreenDevice();
screenWidth = gd.getDisplayMode().getWidth();
screenHeight = gd.getDisplayMode().getHeight();
maynFrame.setPreferredSize(new Dimension(screenWidth,screenHeight - 100));
maynFrame.setContentPane(getContentPanel());
maynFrame.setVisible(true);
maynFrame.pack();
}
public JPanel getContentPanel()
{
if (contentPanel == null)
{
contentPanel = new JPanel();
contentPanel.setPreferredSize(new Dimension(screenWidth,screenHeight - 100));
contentPanel.setBorder(new LineBorder(Color.BLUE));
contentPanel.setBackground(Color.RED);
contentPanel.setLayout(new BorderLayout());
contentPanel.add(getSimPanel(),BorderLayout.CENTER);
}
return contentPanel;
}
public SimPanel getSimPanel()
{
if(simPanel == null)
{
simPanel = new SimPanel(this);
}
return simPanel;
}
public static void main(String[] args)
{
EventQueue.invokeLater(new Runnable()
{
public void run()
{
System.out.println("Start");
Maybee maybee = new Maybee();
maybee.run();
}
});
}
public void run()
{
init();
}
}
and now the first external JPanel class
package com.maybee.gui;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JPanel;
public class SimPanel extends JPanel
{
public Maybee localMaybee = null;
public JPanel simPanel = null;
private JButton btn;
public SimPanel(Maybee interMaybee)
{
localMaybee = interMaybee;
init();
}
public void init()
{
simPanel = new JPanel();
simPanel.setLayout(new BorderLayout());
simPanel.setPreferredSize(new Dimension(localMaybee.screenWidth/4,localMaybee.screenHeight - 100));
simPanel.setBackground(Color.GREEN);
simPanel.add(getBtn(),BorderLayout.CENTER);
simPanel.setVisible(true);
System.out.println("IN SIM" + localMaybee.screenWidth);
}
public JButton getBtn()
{
if(btn == null)
{
btn = new JButton("ENDE");
btn.setSize(70, 20);
btn.setForeground(Color.YELLOW);
btn.addActionListener(new ActionListener()
{
#Override
public void actionPerformed(ActionEvent e)
{
}
});
}
return btn;
}
}
So what am I missing?
Many thanks!
The immediate issue is the second instance of JPanel created in SimPanel.init(). SimPanel is already a JPanel, there is no need to maintain public JPanel simPanel member.
The same problem is in the Maybee class which extends JFrame, but maintains public JFrame maynFrame member.
Also, as already mentioned in comments above (thanks #Frakcool!) :
Make sure to call pack() before setVisible();
Don't call setPreferredSize(), do override getPreferredSize() intead;
No need to extend JFrame;
No need to call setVisible on JPanel;
Don't call btn.setSize(), it is a job for a layout manager;
No need for setContentPane(), JFrame by default has a JPanel as content pane with BorderLayout. Calling add() is enough in this case.
Here is a slightly modified version of the original code (simplified for clarity):
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class Maybee2 {
static class SimPanel extends JPanel {
public SimPanel() {
setLayout(new BorderLayout());
JButton btn = new JButton("ENDE");
btn.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
//TODO
}
});
add(btn, BorderLayout.CENTER);
}
#Override
public Dimension getPreferredSize() {
return new Dimension(300, 200);
}
}
private static void createAndShowGUI() {
final JFrame frame = new JFrame("Maybee");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
SimPanel simPanel = new SimPanel();
frame.add(simPanel);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGUI();
}
});
}
}
EDIT:
The application may consist of many panels. The high level container such as JFrame is not aware of all the underlying layout complexities and cannot enforce a certain size. The panel itself knows its internal layout and its content. So the panel reports its preferred size to the layout manager which eventually packs the content. See Laying Out Components Within a Container for more information.
setBackground has its effect although the button occupies the center of the BorderLayout which takes all the space of the panel. Change the layout of the panel and see the effect. Or move the button into another area, ie - add(btn, BorderLayout.NORTH); Read more in A Visual Guide to Layout Managers.
I have written a custom glasspane component and set that to my JFrame and JDialog classes.
I don't intercept mouse events in the custom glasspane, as I don't need to and also because there are a number of components on the GUI e.g. trees, popups etc which makes it complicated trying to intercept and forward mouse events.
Everything works fine as is - except that whenever I call getMousePosition() on any of the other components (e.g. JPanel) in the frame/dialog it returns null.
On my JFrame and JDialog classes, I have set the glasspane to disabled (but visible) and it works for the most part. What do I need to do so the getMousePosition() method returns the correct value without having to add mouse event listeners to the glasspane component.
Sample code that demonstrates the problem.
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionListener;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
public class GlassPaneExample
{
private JPanel panel;
private JButton btn;
private JLabel response;
private int counter = 0;
GlassPaneExample()
{
buildUI();
}
private void buildUI()
{
JFrame frame = new JFrame("GlassPane Example");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(getPanel());
frame.setGlassPane(new MyGlassPane());
frame.getGlassPane().setVisible(true);
frame.getGlassPane().setEnabled(false);
frame.setPreferredSize(new Dimension(200, 220));
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
JPanel getPanel()
{
panel = new JPanel(new BorderLayout());
panel.addMouseMotionListener(new MouseMotionListener() {
#Override
public void mouseDragged(MouseEvent e)
{
}
#Override
public void mouseMoved(MouseEvent e)
{
System.out.println("mousePosition : " + panel.getMousePosition());
System.out.println("mousePosition(true) : " + panel.getMousePosition(true));
}
});
btn = new JButton("Click here...");
btn.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e)
{
response.setText("Button click number " + getButtonClickCount());
}
});
response = new JLabel();
response.setToolTipText("Response label");
panel.add(btn, BorderLayout.NORTH);
panel.add(response, BorderLayout.SOUTH);
return panel;
}
private int getButtonClickCount()
{
return counter++;
}
public static void main(String[] arg)
{
new GlassPaneExample();
}
class MyGlassPane extends JComponent
{
protected void paintComponent(Graphics g)
{
super.paintComponent(g);
g.setColor(Color.GREEN);
g.fillRect(10,40,120,120);
}
}
}
If you comment out the 3 lines to do with adding the glasspane to the Frame, then the mouse position point is printed out correctly.
This is a simple example to illustrate the problem, and I've said above, I dont want to add mouse listeners to the custom glasspane component as it introduces other complications.
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);
}
}
}
I am trying to extend the StyledEditorKit in Swing to be able to include a JLabel inside the editor. I was able to do that and this is what I got so far. In the image below, the highlighted text button is of type JLabel whereas the rest of the text is normal text.
As you can see the label renders a little below than the normal text. How do I align its top with top of the remaining text?
Here is the code for the view that is used to create this label element:
class ComponentView(Element elem) {
#Override
protected Component createComponent() {
JLabel lbl = new JLabel("");
lbl.setOpaque(true);
lbl.setBackground(Color.red);
try {
int start = getElement().getStartOffset();
int end = getElement().getEndOffset();
String text = getElement().getDocument().getText(start, end - start);
lbl.setText(text);
} catch (BadLocationException e) {}
return lbl;
}
}
Try adjusting Component.getAlignmentY that controls the positioning of component relative to the text baseline as suggested in ComponentView.
You could also try using JTextPane that provides easier support for embedded components. Components can be added using insertComponent() method. Here is an example, it also demos setAlignmentY:
import java.awt.BorderLayout;
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.JPanel;
import javax.swing.JTextPane;
import javax.swing.SwingUtilities;
public class TextPaneDemo {
private static void createAndShowGUI() {
final JTextPane pane = new JTextPane();
pane.setText("Some text");
JButton buttonButton = new JButton("Insert label");
buttonButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent event) {
JLabel label = new JLabel("label");
label.setAlignmentY(0.85f);
pane.insertComponent(label);
}
});
JPanel panel = new JPanel(new BorderLayout());
panel.add(buttonButton, BorderLayout.SOUTH);
panel.add(pane, BorderLayout.CENTER);
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(panel);
frame.setSize(400, 200);
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGUI();
}
});
}
}