Develop Reference

A JList rolls down when a JButton is clicked ? JAVA

I basically want to make a JList (whatToSearch) roll-down, or simply show its content, for selection, once a JButton (popDownButton) is clicked.
//SEARCH OPTIONS
popDownButton = new JButton(new ImageIcon(new ImageIcon("downArrow.png").getImage().getScaledInstance(20, 20, Image.SCALE_DEFAULT)));
whatToSearch = new JList(elementsToSearch);
whatToSearch.setVisibleRowCount(3);
whatToSearch.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
scroll = new JScrollPane(whatToSearch);
popDownButton.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent event) {
JOptionPane.showMessageDialog(null, scroll.getViewport());
}
});
add(popDownButton);
This bit of code works, but I'm looking for the content of the JList to be shown in the same interface, next to the button, rather than in another pop-up interface.

You can try this code, it's really easy:
popDownButton.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent event) {
JScrollBar vertical = scroll.getVerticalScrollBar();
vertical.setValue(vertical.getMaximum());
}
});
More ways: Scroll JScrollPane to bottom

Hope this helps:
popDownButton.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent event) {
whatToSearch.setSelectedIndex(elementsToSearch.getSize() - 1);
whatToSearch.ensureIndexIsVisible(elementsToSearch.getSize() - 1);
}
});

How to modify the value of JTextField after automatic item selection from popup menu by mouse click of editable JCombobox

I have an editable JCombobox . I have already done whats required for loading data from database.
After loading the data, I add some extra data like .next. or - for a specific reason. .next. or - which only work when they are highlighted in the popup menu.I have designed their working already.
However I don't want to view/selected .next. or - in JTextField of JComboBox.
For this purpose, I override JCombobox,
searchCBX.addItemListener(new ItemListener() {
#Override
public void itemStateChanged(ItemEvent e) {
if (e.getStateChange() == ItemEvent.SELECTED
&& (".next.".equals(e.getItem()) || "-".equals(e.getItem()))) {
searchTF.setText("");
}
}
});
Here, searchCBX is my required combobox and searchTF is my textfield of searchCBX. It works fine when I try to select .next. or - by scrolling the JPopupmenu from keyboard, searchTF automatically goes to empty.
Now the problem arises when I try to select .next. or - by mouse click from visible popup menu. It gets selected automatically.
I am trying to override mouseListener but it's not working.
searchCBX.addMouseListener(new MouseAdapter() {
#Override
public void mouseClicked(MouseEvent me) {
if ((".next.".equals(searchTF.getText()) || "-".equals(searchTF.getText()))) {
searchTF.setText("");
}
}
});
So how can I remove the selected data from searchTF after mouse click of a jComboBox popup menu where value is .next. or - . Any help would be really appreciated.

To my understand you need to remove the text of the searchTF once you select the .next. or - from the dropdown of the searchCBX. If its the case , you dont need to worry about a MouseListener here. Just the ItemStageChage event can do the work.
Here is a required part of the code :
public class Example extends JFrame {
private JComboBox searchCBX;
private JTextField searchTF;
/**
* Creates new form Example
*/
public Example() {
initComponents();
}
private void initComponents() {
searchCBX = new JComboBox();
searchTF = new JTextField();
searchCBX.addItemListener(new ItemListener() {
public void itemStateChanged(ItemEvent evt) {
searchCBXItemStateChanged(evt);
}
});
}
private void searchCBXItemStateChanged(ItemEvent evt) {
if (evt.getStateChange() == ItemEvent.SELECTED
&& (".next.".equals(evt.getItem()) || "-".equals(evt.getItem()))) {
searchTF.setText("");
} else {
searchTF.setText(searchCBX.getSelectedItem().toString());
}
}
}

Java how to assign id to button and retrieve them?

I'm getting stuck while building a forum like application which has a vote button.
I have vote up and vote down button for each content which are automatically generated. I want this button to only display the up and down arrow but not any text or label.. how can i find out which button is pressed?
Automated content..
ImageIcon upvote = new ImageIcon(getClass().getResource("vote_up.png"));
ImageIcon downvote = new ImageIcon(getClass().getResource("vote_down.png"));
JButton vote_up = new JButton(upvote);
JButton vote_down = new JButton(downvote);
vote_up.addActionListener(voting);
vote_down.addActionListener(voting);
Action voting = new AbstractAction(){
#Override
public void actionPerformed(ActionEvent e){
//What to do here to find out which button is pressed?
}
};
any help is appreciated.
public void a(){
int crt_cnt = 0;
for(ClassA temp : listofClassA)
{
b(crt_cnt);
crt_cnt++;
}
}
public void b(crt_cnt){
//draw button
}
As from above, I have multiple vote_up and vote_down button created by the b function, how can i differentiate which crt_cnt is the button from?

There are multiple ways you might achieve this
You could...
Simply use the source of the ActionEvent
Action voting = new AbstractAction(){
#Override
public void actionPerformed(ActionEvent e){
if (e.getSource() == vote_up) {
//...
} else if (...) {
//...
}
}
};
This might be okay if you have a reference to the original buttons
You could...
Assign a actionCommand to each button
JButton vote_up = new JButton(upvote);
vote_up.setActionCommand("vote.up");
JButton vote_down = new JButton(downvote);
vote_down .setActionCommand("vote.down");
//...
Action voting = new AbstractAction(){
#Override
public void actionPerformed(ActionEvent e){
if ("vote.up".equals(e.getActionCommand())) {
//...
} else if (...) {
//...
}
}
};
You could...
Take full advantage of the Action API and make indiviual, self contained actions for each button...
public class VoteUpAction extends AbstractAction {
public VoteUpAction() {
putValue(SMALL_ICON, new ImageIcon(getClass().getResource("vote_up.png")));
}
#Override
public void actionPerformed(ActionEvent e) {
// Specific action for up vote
}
}
Then you could simply use
JButton vote_up = new JButton(new VoteUpAction());
//...
Which will configure the button according to the properties of the Action and will trigger it's actionPerformed method when the button is triggered. This way, you know 100% what you should/need to do when the actionPerformed method is called, without any doubts.
Have a closer look at How to Use Actions for more details

You can detect by using the method getSource() of your EventAction
Action voting = new AbstractAction(){
#Override
public void actionPerformed(ActionEvent e){
if (e.getSource() == vote_up ) {
// vote up clicked
} else if (e.getSource() == vote_down){
// vote down clicked
}
}
};

hey thanks for all the help and assistance! I've finally got it! I solved it by
assigning a text on the button, +/- for vote up or down, followed by the content id which i required, then change the font size to 0
vote.setText("+"+thistopic.content.get(crt_cnt).get_id());
vote.setFont(heading.getFont().deriveFont(0.0f));
after that i could easily trace which button is pressed by comparing to the
actionEvent.getActionCommand()
which return the text on the button!

I would wrap the JButton similar to this:
JButton createMyButton(final JPanel panel, final String text,
final boolean upOrDown, final int gridx, final int gridy) {
final JButton button = new JButton();
button.setPreferredSize(new Dimension(80, 50));
final GridBagConstraints gbc = Factories.createGridBagConstraints(gridx,
gridy);
panel.add(button, gbc);
button.addActionListener(new ActionListener() {
#Override
public void actionPerformed(final ActionEvent e) {
myActionPerformed(text, upOrDown);
}
});
return button;
}
You could use an int instead of the text, if more convenient.

ActionListener in java performs action on the second click

I am programming my first complex application in Java, Swing. When I have added ActionListener to my JButton.
ActionListener changeButton = new ActionListener() {
#Override
public void actionPerformed(ActionEvent e){
if(startButton.getText() == "Spustit") {
startButton.setText("STOP");
} else {
startButton.setText("Spustit");
}
}
}
I am adding ActionListener to the button itself
private void startButtonActionPerformed(java.awt.event.ActionEvent evt) {
startButton.addActionListener(changeButton);
}
Can you tell me where I coded ActionListener badly?
Thanks to all!

You have coded the ActionListener good enough to be working, at least, for the action listener itself. The problem is that you are adding the action listener after an event (your second sample), thus your action listener will get called the second time you will click it.
A solution is very simple:
JButton button = new JButton();
button.addActionListener( new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
//...
}
});
Now the action listener should activate on the first click if you directly add a new ActionListener to the button, not after an action is performed

Why are you adding the actionlistener in actionPerformed? I think you should do something like this:
public static void main(String[] args) {
final JButton startButton = new JButton("Spustit");
ActionListener changeButton = new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
if (startButton.getText() == "Spustit") {
startButton.setText("STOP");
} else {
startButton.setText("Spustit");
}
}
};
startButton.addActionListener(changeButton);
// Add it to your panel where you want int
}

Right click on JButton

I am trying to write a Minesweeper clone in Java for fun. I have a grid of JButtons whose labels I will change to represent the danger count, flags, etc.
My problem is, I don't know how to get a right click on a JButton to depress the button. I've done the following:
button.addMouseListener(new MouseAdapter(){
public void mouseClicked(MouseEvent e){
boolean mine = field.isMine(x, y);
if (e.isPopupTrigger()) {
button.setText("F");
}
else {
if (mine) {
button.setText("X");
}
}
}
});
This doesn't seem to be working at all; the "F" is never shown, only the "X" part. But more importantly, this does nothing for depressing the button.
EDIT: Macs have popup trigger happen on mousePress, not mouseClick.
EDIT: Here's the solution I worked out based off of accepted answer:
button.addMouseListener(new MouseAdapter(){
boolean pressed;
#Override
public void mousePressed(MouseEvent e) {
button.getModel().setArmed(true);
button.getModel().setPressed(true);
pressed = true;
}
#Override
public void mouseReleased(MouseEvent e) {
//if(isRightButtonPressed) {underlyingButton.getModel().setPressed(true));
button.getModel().setArmed(false);
button.getModel().setPressed(false);
if (pressed) {
if (SwingUtilities.isRightMouseButton(e)) {
button.setText("F");
}
else {
button.setText("X");
}
}
pressed = false;
}
#Override
public void mouseExited(MouseEvent e) {
pressed = false;
}
#Override
public void mouseEntered(MouseEvent e) {
pressed = true;
}
});
add(button);
Minesweeper clone http://grab.by/1y9z

Button can't be pressed by right click. Add such a lines to you mouse listener
mousePressed:
if(isRightButtonPressed) {underlyingButton.getModel().setPressed(true));
mouseReleased:
if(needReset) {underlyingButton.getModel().setPressed(false));
or do there whatever want.

I wouldn't use isPopupTrigger but directly check for the right button:
button.addMouseListener(new MouseAdapter(){
public void mouseClicked(MouseEvent e){
boolean mine = field.isMine(x, y);
if (e.getButton() == MouseEvent.BUTTON2) {
button.setText("F");
}
...

Just a small addition: the simplest way to check for the right button is SwingUtilities.isRightMouseButton

As you have mentioned that checking for "mousePressed" solved your issue. And the Javadoc of isPopupTrigger would explain the need for this:
public boolean isPopupTrigger()
...
Note: Popup menus are triggered differently on different systems. Therefore, isPopupTrigger should be checked in both mousePressed and mouseReleased for proper cross-platform functionality.
Also see the section on The Mouse Listener API in the Java Swing tutorial.

MouseEvent has some properties
static int BUTTON1
static int BUTTON2
static int BUTTON3
among others. Check those when your event fires.
EDIT
public int getButton()
Returns which, if any, of the mouse buttons has changed state.

The button being visibly depressed on right click isn't part of the "normal" behavior of buttons. You may be able to fake it using JToggleButtons, or simply changing the button's background color and maybe border while the right mouse button is being held down.

If you are certain that the event is properly being triggered (debug FTW!) and that the button.setText("F") is happening, then perhaps you simply need to repaint.
Repaint the button.
http://java.sun.com/javase/6/docs/api/javax/swing/JComponent.html#repaint(java.awt.Rectangle)

This works for me fine on Mac:
import java.awt.event.*;
import javax.swing.*;
public class ButtonTest extends JFrame {
JButton button;
public ButtonTest() {
button = new JButton("W");
button.addMouseListener(new MouseAdapter() {
public void mouseClicked(MouseEvent e) {
if (e.getButton() == 3) { // if right click
button.setText("F");
button.getModel().setPressed(false);
// button.setEnabled(true);
} else {
button.setText("X");
button.getModel().setPressed(true);
// button.setEnabled(false);
}
}
});
this.add(button);
this.setVisible(true);
}
public static void main(String[] args) {
new ButtonTest();
}
}
You might as well check for e.getButton() == 2 but I don't know when this one is triggered on Macs.