Update a JPopupMenu menu items while it is open

Update a JPopupMenu menu items while it is open - java

In my UI i have a JPopMenu with values as ,
for e.g A,B,C
The scenario is,
I opened the JPopupMenu and kept it open.
At back end with a timer running , it updates the content B to some other alphabet at frequent interval.
3.I want the JPopupMenu to get updated while it is kept open.
In current behavior if i close and open JPopupMenu the updated value shows up.
I tried repaint()but it doesn't do anything.
What is the best way to do this?? Am new to swings please help.

Menu items can change their content at run time just fine. Without seeing your code it's hard to tell what you're doing wrong, but here's a working example:
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JMenuItem;
import javax.swing.JPopupMenu;
import javax.swing.SwingUtilities;
import javax.swing.Timer;
import javax.swing.event.PopupMenuEvent;
import javax.swing.event.PopupMenuListener;
public class PopupTest {
private static final String[] messages = {
"You are today's 1000th user!",
"You have won an internet!",
"Claim your prize!"
};
private PopupTest() {
JFrame frame = new JFrame("You have won");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JLabel lbl = new JLabel("Check your prize!");
frame.setLocationByPlatform(true);
frame.add(lbl);
frame.pack();
final JPopupMenu menu = new JPopupMenu();
final JMenuItem item = new JMenuItem(messages[0]);
menu.add(item);
menu.add(new JMenuItem("Another item that does not work"));
final Timer timer = new Timer(1000, new ActionListener() {
int count;
#Override
public void actionPerformed(ActionEvent e) {
count++;
count %= messages.length;
item.setText(messages[count]);
}
});
menu.addPopupMenuListener(new PopupMenuListener() {
#Override
public void popupMenuWillBecomeVisible(PopupMenuEvent e) {
}
#Override
public void popupMenuWillBecomeInvisible(PopupMenuEvent e) {
timer.stop();
}
#Override
public void popupMenuCanceled(PopupMenuEvent e) {
timer.stop();
}
});
lbl.addMouseListener(new MouseAdapter() {
#Override
public void mousePressed(MouseEvent e) {
maybeShowPopup(e);
}
#Override
public void mouseReleased(MouseEvent e) {
maybeShowPopup(e);
}
private void maybeShowPopup(MouseEvent e) {
if (e.isPopupTrigger()) {
menu.show(e.getComponent(), e.getX(), e.getY());
timer.start();
}
}
});
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
new PopupTest();
}
});
}
}

Try to use .revalidate() with .repaint() it might help.
The docs suggest that the revalidate method is called every time something like size changes and manually calling it with repaint seems to solve problems like these.

Related

JComboBox setPopupVisible not called on clicking arrow

When clicking the arrow to open the popup on a JComboBox the overridden setPopupVisible is not called, see minimal example below. Am i just missing something here or doing something wrong? Any hints appreciated :)
The goal here is that i want to control its visibility behaviour, especially only hiding it under certain conditions, for example input checking (mind that the combobox is editable).
Using Java 8.
Building a Frame with a custom JComboBox:
import java.awt.Frame;
import javax.swing.BoxLayout;
public class Test {
public static void main(String[] args) {
Frame frame = new Frame();
frame.setLayout(new BoxLayout(frame, BoxLayout.Y_AXIS));
MyComboBox combo = new MyComboBox();
combo.setEditable(true);
combo.addItem("bli");
combo.addItem("bla");
combo.addItem("blu");
combo.addItem("ble");
frame.add(combo);
frame.pack();
frame.setVisible(true);
}
}
The custom JComboBox:
import javax.swing.JComboBox;
public class MyComboBox extends JComboBox {
#Override
public void setPopupVisible(boolean v) {
if(!v) {
System.out.println("HIDING COMBOBOX");
super.setPopupVisible(v);
} else {
System.out.println("SHOWING COMBOBOX");
super.setPopupVisible(v);
}
}
}

In JComboBox setPopupVisible(boolean) API is NOT there to notify when the popup is opened/closed. It is there to programmatically show the popup or hide the popup.
If you want to be notified when the popup is opened/closed, you can use addPopupMenuListener() like in below code:
import javax.swing.BoxLayout;
import javax.swing.JComboBox;
import javax.swing.event.PopupMenuEvent;
import javax.swing.event.PopupMenuListener;
import java.awt.Frame;
public class Test {
public static void main(String[] args) {
Frame frame = new Frame();
frame.setLayout(new BoxLayout(frame, BoxLayout.Y_AXIS));
MyComboBox combo = new MyComboBox();
combo.setEditable(true);
combo.addItem("bli");
combo.addItem("bla");
combo.addItem("blu");
combo.addItem("ble");
combo.addPopupMenuListener(new PopupMenuListener()
{
#Override
public void popupMenuWillBecomeVisible(PopupMenuEvent e)
{
System.out.println("Popup Menu Will Become Visible");
}
#Override
public void popupMenuWillBecomeInvisible(PopupMenuEvent e)
{
System.out.println("Popup Menu Will Become Invisible");
}
#Override
public void popupMenuCanceled(PopupMenuEvent e)
{
System.out.println("Popup Menu Canceled");
}
});
frame.add(combo);
frame.pack();
frame.setVisible(true);
}
}
class MyComboBox extends JComboBox
{
#Override
public void setPopupVisible(boolean v) {
if(!v) {
System.out.println("HIDING COMBOBOX");
super.setPopupVisible(v);
} else {
System.out.println("SHOWING COMBOBOX");
super.setPopupVisible(v);
}
}
}

Clear JTextField Contents on Click

So I've built a very basic Web browser - I'm trying desperately to remove the contents of the address bar when a user clicks on it (JTextField) this appears with some text in as default. Any advice is appreciated.
Have a great day!
MY CODE
import java.awt.*;
import java.awt.event.*;
import java.io.IOException;
import javax.swing.*;
import javax.swing.event.*;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
public class Web_Browser extends JFrame {
private final JTextField addressBar;
private final JEditorPane display;
// Constructor
public Web_Browser() {
super("Web Browser");
addressBar = new JTextField("Click & Type Web Address e.g. http://www.google.com");
addressBar.addActionListener(
new ActionListener() {
#Override
public void actionPerformed(ActionEvent event) {
loadGo(event.getActionCommand());
}
}
);
add(addressBar, BorderLayout.NORTH);
display = new JEditorPane();
display.setEditable(false);
display.addHyperlinkListener(
new HyperlinkListener(){
#Override
public void hyperlinkUpdate(HyperlinkEvent event){
if(event.getEventType()==HyperlinkEvent.EventType.ACTIVATED){
loadGo(event.getURL().toString());
}
}
}
);
add(new JScrollPane(display), BorderLayout.CENTER);
setSize(500,300);
setVisible(true);
}
// loadGo to sisplay on the screen
private void loadGo(String userText) {
try{
display.setPage(userText);
addressBar.setText(userText);
}catch(IOException e){
System.out.println("Invalid URL, try again");
}
}
}

Use a FocusListener. On focusGained, select all.
addressBar.addFocusListener(new FocusAdapter() {
#Override
public void focusGained(FocusEvent e) {
JTextComponent textComponent = (JTextComponent) e.getSource();
textComponent.selectAll();
}
});
For example:
import java.awt.event.FocusAdapter;
import java.awt.event.FocusEvent;
import javax.swing.*;
import javax.swing.text.JTextComponent;
#SuppressWarnings("serial")
public class FocusExample extends JPanel {
private static final int TF_COUNT = 5;
private JTextField[] textFields = new JTextField[TF_COUNT];
public FocusExample() {
for (int i = 0; i < textFields.length; i++) {
textFields[i] = new JTextField("Foo " + (i + 1), 10);
textFields[i].addFocusListener(new FocusAdapter() {
#Override
public void focusGained(FocusEvent e) {
JTextComponent textComponent = (JTextComponent) e.getSource();
textComponent.selectAll();
}
});
add(textFields[i]);
}
}
private static void createAndShowGui() {
FocusExample mainPanel = new FocusExample();
JFrame frame = new JFrame("FocusExample");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
This gives the user the option of leaving the previous text in place, of adding to the previous text, or of simply over-writing it by typing.

new JTextField("Click & Type Web Address e.g. http://www.google.com");
Maybe you want the Text Prompt, which doesn't actually store any text in the text field. It just gives the user a hint what the text field is for.
This is beneficial so that you don't generate DocumentEvents etc., since you are not actually changing the Document.

Add a mouseListener instead of your actionListener method.
addressBar.addMouseListener(new MouseAdapter(){
#Override
public void mouseClicked(MouseEvent e){
addressBar.setText("");
}

Why does viewport changelistener get called multiple times

I've got a viewport, and I've attached a change listener to it. Whenever I scroll through my viewport, my change listener gets called about four times. I'm not sure how to avoid this; I only want the call to happen once?

There's no way around this, JViewport will fire several stateChanged events because it's providing notification about changes to a number of properties...
From the JavaDocs...
Adds a ChangeListener to the list that is notified each
time the view's size, position, or the viewport's extent size has
changed.
At this point, it's kind of hard to know what to suggest as we don't know what it is you are trying to achieve, however, if you have to use a ChangeListener, you could set up a coalescing mechanism. That is, rather then responding to each event, you basically wait until a long enough delay has occurred between events before responding to it...
For example...
public class DelayedChangeHandler implements ChangeListener {
private Timer timer;
private ChangeEvent last;
public DelayedChangeHandler() {
timer = new Timer(250, new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
stableStateChanged();
}
});
timer.setRepeats(false);
}
#Override
public void stateChanged(ChangeEvent e) {
last = e;
timer.restart();
}
protected void stableStateChanged() {
System.out.println("Finally...");
}
}
Basically, this is a ChangeListener implementation that uses a non-repeating javax.swing.Timer with a short delay. Each time stateChanged is called, the timer is restart. Finally, when the timer is allowed to "tick", it calls stableStateChanged indicating that enough time has passed since the last event was raised.
This assumes that you don't so much care about what caused the event, only that the event occured...
A runnable example...
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.Timer;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;
public class TestViewport {
public static void main(String[] args) {
new TestViewport();
}
public TestViewport() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
}
JPanel pane = new JPanel() {
#Override
public Dimension getPreferredSize() {
return new Dimension(1000, 1000);
}
};
JScrollPane sp = new JScrollPane(pane);
sp.getViewport().addChangeListener(new DelayedChangeHandler());
sp.getViewport().addPropertyChangeListener(new PropertyChangeListener() {
#Override
public void propertyChange(PropertyChangeEvent evt) {
System.out.println(evt.getPropertyName());
}
});
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(sp);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class DelayedChangeHandler implements ChangeListener {
private Timer timer;
private ChangeEvent last;
public DelayedChangeHandler() {
timer = new Timer(250, new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
stableStateChanged();
}
});
timer.setRepeats(false);
}
#Override
public void stateChanged(ChangeEvent e) {
last = e;
timer.restart();
}
protected void stableStateChanged() {
System.out.println("Finally...");
}
}
}

You can try to use AdjustmentListener for gettign scroll event once, try next:
import java.awt.event.AdjustmentEvent;
import java.awt.event.AdjustmentListener;
import java.io.UnsupportedEncodingException;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
public class Example {
public static void main(String[] args) throws UnsupportedEncodingException {
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
final JScrollPane pane = new JScrollPane(new JTextArea());
pane.getVerticalScrollBar().addAdjustmentListener(new AdjustmentListener() {
#Override
public void adjustmentValueChanged(AdjustmentEvent e) {
if(e.getValueIsAdjusting()){
return;
}
System.out.println("vertical scrolled");
System.out.println("bar value = " + e.getValue());
}
});
frame.setContentPane(pane);
frame.setSize(300, 200);
frame.setVisible(true);
}
}
Here is another example.

JPopupMenu not showing on the screen?

So for my school project I am creating a Class Diagram maker. I am 95% done with it and all I need is to make the Jpopup menu appear. In the core I have 3 files. The ApplicationModel which extends the JFrame, ClassDiagram which extends the JPanel and ClassModel which makes the Rectangles (in the picture) appear. The core of the rendering is on Rectangle objects and the text inside the middle and bottom rectangles are surrounded by another invisible rectangle, which is right-clickable.
This is what the program looks like (Minus the paint editting)
Now for the file that handles the clicking is DiagramMouseListener, here is the code for it.
package edu.mville.cs.classdiagram;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.JMenuItem;
import javax.swing.JPopupMenu;
import javax.swing.SwingUtilities;
public class DiagramMouseListener extends MouseAdapter
{
ClassDiagram diagram;
Field field;
Method method;
int x;
int y;
ClassModel elementBeingDragged;
JPopupMenu fieldPopupMenu = new JPopupMenu();
JPopupMenu methodPopupMenu = new JPopupMenu();
JMenuItem editFieldNameItem;
JMenuItem createFieldItem;
JMenuItem deleteFieldItem;
JMenuItem editMethodNameItem;
JMenuItem createMethodItem;
JMenuItem deleteMethodItem;
public DiagramMouseListener(ClassDiagram diagram) { this.diagram = diagram; }
public void addPopupMenu()
{
editFieldNameItem = new JMenuItem("Edit Field Name");
createFieldItem = new JMenuItem("New Field");
deleteFieldItem = new JMenuItem("Delete Field");
editMethodNameItem = new JMenuItem("Edit Method Name");
createMethodItem = new JMenuItem("New Method");
deleteMethodItem = new JMenuItem("Delete Method");
methodPopupMenu.add(editMethodNameItem);
methodPopupMenu.add(createMethodItem);
methodPopupMenu.add(deleteMethodItem);
fieldPopupMenu.add(editFieldNameItem);
fieldPopupMenu.add(createFieldItem);
fieldPopupMenu.add(deleteFieldItem);
editFieldNameItem.addActionListener(new ActionListener()
{
#Override
public void actionPerformed(ActionEvent ae)
{
}
});
/*
createFieldItem.addActionListener(this);
deleteFieldItem.addActionListener(this);
editMethodNameItem.addActionListener(this);
createMethodItem.addActionListener(this);
deleteMethodItem.addActionListener(this);
*/
}
#Override
public void mouseClicked(MouseEvent me)
{
if(SwingUtilities.isLeftMouseButton(me) && me.getClickCount() == 2)
{
diagram.doubleClick(me.getPoint());
}
}
#Override
public void mousePressed(MouseEvent e)
{
x = e.getX();
y = e.getY();
DiagramElement elt = diagram.containsPoint(e.getPoint());
if (elt instanceof ClassModel)
{
elementBeingDragged = (ClassModel) elt;
}
}
#Override
public void mouseDragged(MouseEvent e)
{
int dx = e.getX() - x;
int dy = e.getY() - y;
if (elementBeingDragged != null)
{
elementBeingDragged.move(dx, dy);
diagram.repaint();
}
x += dx;
y += dy;
}
#Override
public void mouseReleased(MouseEvent me)
{
elementBeingDragged = null;
DiagramElement de = diagram.containsPoint(me.getPoint());
if (SwingUtilities.isRightMouseButton(me) && me.getClickCount() == 1 && de instanceof Field)
{
if (me.isPopupTrigger())
{
System.out.println("it is");
fieldPopupMenu.show(me.getComponent(), me.getX(), me.getY());
}
}
else if (SwingUtilities.isRightMouseButton(me) && me.getClickCount() == 1 && de instanceof Method)
{
if (me.isPopupTrigger())
{
System.out.println("it is");
methodPopupMenu.show(me.getComponent(), me.getX(), me.getY());
}
}
}
}
At line 118 where it says System.out.println("it is"); It successfully displays the text on console, which tells me the code successfully reached that part, but the popup menu is never displayed when I right click the text (which is inside invisible Rectangles separated by 5 pixels of space).
I tried multiple solutions to this problem. I even looked at the oracle tutorials and other user's examples to see what was wrong with my code. But after countless hours of searching, I failed to fix the problem. Any help would be appreciated. Also if you need more information, I will be glad to provide! Thanks.

Several things;
First off, the popup coordinates should be relative to the component you are triggering the popup on, not the screen coordinates. What is happening is, the API is calculating the screen location of the component and adding the x/y values you pass, which is possibly pushing the popup off the screen
fieldPopupMenu.show(me.getComponent(), me.getX(), me.getY());
Secondly, popups can be triggered on different systems by different events. You should be checking for isPopupTrigger in mousePressed, mouseReleased and even mouseClicked.
Lastly, popups can be triggered by different mouse buttons (and even possibly other conditions), so should only need to check isPopupTrigger
Additionally, you could just use JComponent#setComponentPopupMenu
Updated with setComponentPopupMenu example
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.JFrame;
import javax.swing.JMenuItem;
import javax.swing.JPanel;
import javax.swing.JPopupMenu;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class PopupMenuTest {
public static void main(String[] args) {
new PopupMenuTest();
}
public PopupMenuTest() {
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 JPopupMenu popupMenu;
public TestPane() {
popupMenu = new JPopupMenu();
popupMenu.add(new JMenuItem("Open..."));
popupMenu.add(new JMenuItem("Save..."));
popupMenu.add(new JMenuItem("Close..."));
popupMenu.add(new JMenuItem("Give Blood..."));
popupMenu.add(new JMenuItem("Give Money..."));
setComponentPopupMenu(popupMenu);
}
#Override
public Dimension getPreferredSize() {
return new Dimension(200, 200);
}
}
}
Updated with MouseListener example
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.JFrame;
import javax.swing.JMenuItem;
import javax.swing.JPanel;
import javax.swing.JPopupMenu;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class PopupMenuTest {
public static void main(String[] args) {
new PopupMenuTest();
}
public PopupMenuTest() {
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 JPopupMenu popupMenu;
public TestPane() {
popupMenu = new JPopupMenu();
popupMenu.add(new JMenuItem("Open..."));
popupMenu.add(new JMenuItem("Save..."));
popupMenu.add(new JMenuItem("Close..."));
popupMenu.add(new JMenuItem("Give Blood..."));
popupMenu.add(new JMenuItem("Give Money..."));
addMouseListener(new MouseAdapter() {
protected void doPopup(MouseEvent evt) {
if (evt.isPopupTrigger()) {
popupMenu.show(evt.getComponent(), evt.getX(), evt.getY());
}
}
#Override
public void mouseClicked(MouseEvent e) {
doPopup(e);
}
#Override
public void mousePressed(MouseEvent e) {
doPopup(e);
}
#Override
public void mouseReleased(MouseEvent e) {
doPopup(e);
}
});
}
#Override
public Dimension getPreferredSize() {
return new Dimension(200, 200);
}
}
}

Changing value of boolean when mouse cursor hovers over a JButton

I have a button that will change from black to gray when you hover over, I do this with setRolloverIcon(ImageIcon);. Is there any easy way to make a boolean equals to true while the mouse cursor hovers over the JButton or would I have to use a MouseMotionListener to check the position of the mouse cursor?

Is there any easy way to make a boolean equals to true while the mouse
cursor hovers over the JButton
you can to add ChangeListener to ButtonModel, e.g.
JButton.getModel().addChangeListener(new ChangeListener() {
#Override
public void stateChanged(ChangeEvent e) {
ButtonModel model = (ButtonModel) e.getSource();
if (model.isRollover()) {
//do something with Boolean variable
} else {
}
}
});

This is an example of using the ButtonModel:
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.SwingUtilities;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;
public class TestButtons {
protected void createAndShowGUI() {
JFrame frame = new JFrame("Test button");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
final JButton button = new JButton("Hello");
button.getModel().addChangeListener(new ChangeListener() {
#Override
public void stateChanged(ChangeEvent e) {
if (button.getModel().isRollover()) {
button.setText("World");
} else {
button.setText("Hello");
}
}
});
frame.add(button);
frame.pack();
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
new TestButtons().createAndShowGUI();
}
});
}
}

Try this:
button.addMouseListener(new MouseListener() {
public void mouseEntered(MouseEvent e) {
yourBoolean = true;
}
}
good luck

Develop Reference

Java is a programming language and computing platform first released by Sun Microsystems in 1995.

Update a JPopupMenu menu items while it is open - java

Try to use .revalidate() with .repaint() it might help. The docs suggest that the revalidate method is called every time something like size changes and manually calling it with repaint seems to solve problems like these.

Related

JComboBox setPopupVisible not called on clicking arrow

Clear JTextField Contents on Click

Why does viewport changelistener get called multiple times

JPopupMenu not showing on the screen?

Changing value of boolean when mouse cursor hovers over a JButton

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