Develop Reference

how to get selected row when click on combobox in table

I have a table and at each row i have a combox of operator from which we can choose any operator and value1 field value 2 field. COMBO BOX DEFAULT OPERATOR IS " EQUAL TO".so my question is when u click on combobox in any row i should get the value of the selected row and get the operator which i am selecting such that i can perform some operation based on selected operator....
Or else if i change the combobox operator from in between to equal to i should get clear the value 2 field....
Help me get out of this..

You should have an event to know item in the combo is clicked.
Like this:
combo.addActionListener (new ActionListener () {
public void actionPerformed(ActionEvent e) {
//doSomething();
}
});
You have three methods to get current item selected:
Will get the index of the item is order number.
int selectedIndex = myComboBox.getSelectedIndex();
-or-
Will get item selected with Object. You can do many method contains in this Object.
Object selectedObject = myComboBox.getSelectedValue();
-or-
Will get real values of item selected with string type.
String selectedValue = myComboBox.getSelectedValue().toString();
You can see full example code at here (from #secario member):
import java.awt.FlowLayout;
import java.awt.event.*;
import javax.swing.*;
public class MyWind extends JFrame{
public MyWind() {
initialize();
}
private void initialize() {
setSize(300, 300);
setLayout(new FlowLayout(FlowLayout.LEFT));
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
final JTextField field = new JTextField();
field.setSize(200, 50);
field.setText(" ");
JComboBox comboBox = new JComboBox();
comboBox.setEditable(true);
comboBox.addItem("item1");
comboBox.addItem("item2");
//
// Create an ActionListener for the JComboBox component.
//
comboBox.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent event) {
//
// Get the source of the component, which is our combo
// box.
//
JComboBox comboBox = (JComboBox) event.getSource();
Object selected = comboBox.getSelectedItem();
if(selected.toString().equals("item1"))
field.setText("30");
else if(selected.toString().equals("item2"))
field.setText("40");
}
});
getContentPane().add(comboBox);
getContentPane().add(field);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
new MyWind().setVisible(true);
}
});
}
}

Items in ComboBox

I am tying to perform and action when an item in combo box are selected, but it performs an action no matter what item is selected.Can someone help me out please.
//number of players combo box
players = new JComboBox();
contentPane.add(players, BorderLayout.SOUTH);
players.addItem("1 Player");
players.addItem("2 Players");
players.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
makeFrame();
}
});
players.addItem("3 Players");
//end of combo box

In order to change behavior based on which item was selected, you will need to retrieve the selected value inside your ActionListener and change the behavior based on the selected value. You could use something like the following:
//number of players combo box
//notice that you have to declare players
//as final. If it is a member of the class,
//you can declare it final in the field
//declaration and initialize it in the
//constructor, or if local, just leave it
//as it is here. Unless using Java 8, then it
//doesn't need to be declared final
final JComboBox players = new JComboBox();
contentPane.add(players, BorderLayout.SOUTH);
players.addItem("1 Player");
//your combo box still needs to be final
final JComboBox players = new JComboBox();
contentPane.add(players, BorderLayout.SOUTH);
players.addItem("1 Player");
players.addItem("2 Players");
players.addItem("3 Players");
players.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
String selectedValue = String.valueOf(players.getSelectedItem());
if (selectedValue != null && (selectedValue.equals("1 Player") || selectedValue.equals("2 Players"))) {
makeFrame();
}
else {
//do something else
}
}
});
//end of combo box
If you happen to know the index ahead of time (i.e., you statically initialize the list of options instead of dynamically generating the list), you could also just refer to .getSelectedIndex() to retrieve the index as follows:
//number of players combo box
//the combo box still needs to be final here
final JComboBox players = new JComboBox();
contentPane.add(players, BorderLayout.SOUTH);
players.addItem("1 Player");
//your combo box still needs to be final
final JComboBox players = new JComboBox();
contentPane.add(players, BorderLayout.SOUTH);
players.addItem("2 Players");
players.addItem("3 Players");
players.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
int myIndex = players.getSelectedIndex();
if (myIndex == 0 || myIndex == 1) {
makeFrame();
}
else {
//do something else
}
}
});
//end of combo box

How can I access an Array List's elements inside an ActionListener from another ActionListener?

I have two Action Listener inner-classes inside one main class. Each one corresponds to its own button. One of the Action Listeners is coded to generate an Array List. The other simply writes that Array List to a Text Field.
My question is how can I refer to/access that data from the other Action Listener? The code below compiles but when I check the contents of the Array List from the second Action Listener, it is empty ([]).
I'm guessing this has something to do with the Array List re-instantiating when the other Action Listener's actionPerformed method is called. How can I work around this? (The code here is just the 2 Action Listeners).
// Create a Button Listener Inner Class for Input Route Button.
class InputRouteButtonHandler implements ActionListener {
List<String> routeStopList = new ArrayList<String>();
public void actionPerformed(ActionEvent event) {
String city1 = (String) cityCombo1.getSelectedItem();
String city2 = (String) cityCombo2.getSelectedItem();
if (city1.equals(city2)) {
JOptionPane.showMessageDialog(null, "Invalid route chosen. Please choose two different cities.");
} else {
routeStopList.add(city1); //Add city1 to start of array.
int dialogResult;
do {
String routeStop = JOptionPane.showInputDialog("Enter a stop between the 2 cities:");
routeStopList.add(routeStop);
dialogResult = JOptionPane.showConfirmDialog(null, "Add another stop?");
} while (dialogResult.equals(JOptionPane.YES_OPTION));
routeStopList.add(city2); //Add city2 to end of array.
System.out.println(routeStopList); //Just checking ArrayList contents
}
}
}
// Create a Button Listener Inner Class for Route Button.
class RouteButtonHandler extends InputRouteButtonHandler implements ActionListener {
public void actionPerformed(ActionEvent event) {
String city1 = (String) cityCombo1.getSelectedItem();
String city2 = (String) cityCombo2.getSelectedItem();
System.out.println(routeStopList); //Just checking ArrayList contents
if (city1.equals(city2)) {
JOptionPane.showMessageDialog(null, "Invalid route chosen. Please choose two different cities.");
} else {
for (int i = 0; i < routeStopList.size(); i++) {
String addedRoute = routeStopList.get(i);
adminPanelTextArea.append(addedRoute + "\n");
}
}
}
}

You are right, your problem is due to your creating two ArrayLists, lists that have absolulely no relationship with each other, other than holding the same type of objects and having the same names. A solution is to create one Model class that is shared by both ActionListener classes, and in this model class, have your ArrayList. Then give your ArrayList classes a setModel(Model model) method or constructor, and pass in a reference to the single Model object into both ActionListeners.
One other consideration is to use a single Control class to handle your listener type code, and then have your Control class hold a Model field.
As an aside, this is dangerous code:
if (city1 == city2) {
Don't compare Strings using ==. Use the equals(...) or the equalsIgnoreCase(...) method instead. Understand that == checks if the two objects are the same which is not what you're interested in. The methods on the other hand check if the two Strings have the same characters in the same order, and that's what matters here.
For example, say you have two buttons that want to manipulate a JList, one wanting to add text, the other wanting to clear it, then you could pass the JList's model into both button handlers. An example program could look like:
import java.awt.BorderLayout;
import java.awt.event.*;
import javax.swing.*;
#SuppressWarnings("serial")
public class ShareList extends JPanel {
private static final String PROTOTYPE_CELL_VALUE = "ABCDEFGHIJKLMNOP";
private static final int VISIBLE_ROW_COUNT = 10;
private JTextField textField = new JTextField(10);
private DefaultListModel<String> listModel = new DefaultListModel<>();
private JList<String> myList = new JList<>(listModel);
public ShareList() {
myList.setPrototypeCellValue(PROTOTYPE_CELL_VALUE);
myList.setVisibleRowCount(VISIBLE_ROW_COUNT);
myList.setFocusable(false);
JPanel buttonPanel = new JPanel();
AddHandler addHandler = new AddHandler(listModel, this);
textField.addActionListener(addHandler);
buttonPanel.add(new JButton(addHandler));
buttonPanel.add(new JButton(new ClearHandler(listModel)));
JPanel rightPanel = new JPanel(new BorderLayout());
rightPanel.add(textField, BorderLayout.NORTH);
rightPanel.add(buttonPanel, BorderLayout.CENTER);
setLayout(new BoxLayout(this, BoxLayout.LINE_AXIS));
add(new JScrollPane(myList));
add(rightPanel);
}
public String getText() {
textField.selectAll();
return textField.getText();
}
private static void createAndShowGui() {
JFrame frame = new JFrame("ShareList");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(new ShareList());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
#SuppressWarnings("serial")
class AddHandler extends AbstractAction {
private DefaultListModel<String> listModel;
private ShareList shareList;
public AddHandler(DefaultListModel<String> listModel, ShareList shareList) {
super("Add");
putValue(MNEMONIC_KEY, KeyEvent.VK_A);
this.listModel = listModel;
this.shareList = shareList;
}
public void actionPerformed(ActionEvent e) {
String text = shareList.getText();
listModel.addElement(text);
};
}
#SuppressWarnings("serial")
class ClearHandler extends AbstractAction {
private DefaultListModel<String> listModel;
public ClearHandler(DefaultListModel<String> listModel) {
super("Clear");
putValue(MNEMONIC_KEY, KeyEvent.VK_C);
this.listModel = listModel;
}
public void actionPerformed(ActionEvent e) {
listModel.clear();
};
}

Clicking a JButton consecutively

Is there a way to know if a JButton was clicked consecutively? Consider my code.
public void actionPerformed(ActionEvent arg0) {
String bucky[] = new String[2];
String firstclick = null, secondclick = null;
clicks++;
if (clicks == 1) {
bucky[0] = firstclick;
} else if(clicks == 2) {
bucky[1] = secondclick;
if (bucky[0] == bucky[1]) {
//This JButton was clicked twice in a row.
}
}
This code checks the entire number of times my JButton was clicked and displays the message "This button was clicked twice in a row". What I want is to compare two clicks from that button and see if they come one after the other rather than counting the number of clicks made. Or is there a built-in function that does this?

Just use a field remembering what the last clicked button was:
private JButton lastButtonClicked;
...
someButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
if (lastButtonClicked == e.getSource()) {
displayError();
}
else {
lastButtonClicked = (JButton) e.getSource();
doSomething();
}
}
});
Of course, you'll have to do the same thing with all the other buttons.

I have a different approach to your problem:
You want to not allow the user to press the same button in some group of buttons twice in a row.
You're solutions so far have tried to check which button was pressed last, and then warn the user if the same button has been pressed in a row.
Perhaps a better solution is to create a construct that simply doesn't allow the user to press the same button twice in a row.
You can create your ButtonGroup like object that selectively disables the last button pressed, and enables all the other buttons.
You would give this class an add(AbstractButton btn) method to allow you to add all the buttons that you wish to behave this way to it. The button would then be added to an ArrayList.
You would give it a single ActionListener that listens to all the buttons. Whenever the actionPerformed method has been pressed, it enables all of the buttons, and then selectively disables the last button pressed.
For instance consider my class below:
public class NoRepeatButtonGroup implements ActionListener {
private List<AbstractButton> btnList = new ArrayList<>();
public void add(AbstractButton btn) {
btnList.add(btn);
btn.addActionListener(this);
}
#Override
public void actionPerformed(ActionEvent evt) {
for (AbstractButton btn : btnList) {
btn.setEnabled(true);
}
((AbstractButton) evt.getSource()).setEnabled(false);
}
public void reset() {
for (AbstractButton btn : btnList) {
btn.setEnabled(true);
}
}
}
If you create a single object of this in your class that creates the buttons, and add each button to the object of this class, your code will automatically disable the last button pressed, and re-enable it once another button has been pressed.
You could use it like so:
JPanel buttonPanel = new JPanel(new GridLayout(1, 0, 5, 0));
NoRepeatButtonGroup noRepeatButtonGroup = new NoRepeatButtonGroup();
JButton yesButton = new JButton(new YesAction());
noRepeatButtonGroup.add(yesButton);
buttonPanel.add(yesButton);
JButton noButton = new JButton(new NoAction());
noRepeatButtonGroup.add(noButton);
buttonPanel.add(noButton);
JButton maybeButton = new JButton(new MaybeAction());
noRepeatButtonGroup.add(maybeButton);
buttonPanel.add(maybeButton);
For example, here is a proof of concept minimal runnable example:
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.ArrayList;
import java.util.List;
import javax.swing.*;
public class NoneInARowBtns {
private static void createAndShowGui() {
JPanel buttonPanel = new JPanel(new GridLayout(1, 0, 5, 0));
NoRepeatButtonGroup noRepeatButtonGroup = new NoRepeatButtonGroup();
int buttonCount = 5;
for (int i = 0; i < buttonCount; i++) {
JButton btn = new JButton(new ButtonAction(i + 1));
noRepeatButtonGroup.add(btn);
buttonPanel.add(btn);
}
JOptionPane.showMessageDialog(null, buttonPanel);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
#SuppressWarnings("serial")
class ButtonAction extends AbstractAction {
public ButtonAction(int i) {
super("Button " + i);
}
#Override
public void actionPerformed(ActionEvent e) {
System.out.println(e.getActionCommand() + " Pressed");
}
}
class NoRepeatButtonGroup implements ActionListener {
private List<AbstractButton> btnList = new ArrayList<>();
public void add(AbstractButton btn) {
btnList.add(btn);
btn.addActionListener(this);
}
#Override
public void actionPerformed(ActionEvent evt) {
for (AbstractButton btn : btnList) {
btn.setEnabled(true);
}
((AbstractButton) evt.getSource()).setEnabled(false);
}
public void reset() {
for (AbstractButton btn : btnList) {
btn.setEnabled(true);
}
}
}
When the above program runs, and when the second button is pressed, you will see that it is disabled:
Then when the 3rd button has been pressed, the 2nd is re-enabled, and the 3rd one is disabled:
And etc for the 4th button....

A global variable arrau of booleans, one for each button, set true on first click, set false or second, sjould do it

Trouble with RadioButtons and booleans connection

Well its weird. I am not good with radiobuttons by the way. But I made a JPanel program in netbeans which includes a RadioButton. You enter all this information with JTextFields(no problem) and then lastly I had a JButton which you click the choice you want. Then I have a JButton that takes all the information and outputs this. For the RadioButton, I first entered the usual:
family = new JRadioButton("Family", true);
friend = new JRadioButton("Friend");
relative = new JRadioButton("Relative");
friendFriend = new JRadioButton("Friend of Friend");
ButtonGroup group = new ButtonGroup();
group.add (friend);
group.add (family);
group.add (relative);
group.add (friendFriend);
(I'm not sure if I needed a listner for the RadioButtons or not but my program still seems to "crash" no matter what).
then I had one action listner for the JButton which included all the textfields and radio buttons. But the RadioButton is the issue.
In the action listner I had:
Object source = event.getSource();
if (source == family)
relation1 = true;
else
if (source == friend)
relation2 = true;
else
if(source == relative)
relation3 = true;
else
if(source == friendFriend)
relation4 = true;
Then I made a relation class:
public class Relation {
private boolean arrayFamily, arrayFriend, arrayRelative, arrayFriendFriend;
public Relation(boolean relation1, boolean relation2, boolean relation3,
boolean relation4)
{
this.arrayFamily = relation1;
this.arrayFriend = relation2;
this.arrayRelative = relation3;
this.arrayFriendFriend = relation4;
}
public String relations ()
{
String relationship = null;
if(arrayFamily && !arrayFriend && !arrayRelative && !arrayFriendFriend == true)
{
relationship = "Family";
}
else
if(arrayFriend && !arrayFamily && !arrayRelative &&
!arrayFriendFriend == true)
{
relationship = "Friend";
}
else
if(arrayRelative && !arrayFamily && !arrayFriend &&
!arrayFriendFriend == true)
{
relationship = "Relative";
}
else
if(arrayFriendFriend && !arrayFamily && !arrayFriend &&
!arrayRelative == true)
{
relationship = "Friend of a Friend";
}
return relationship;
}
}
LASTLY back in the action listner, I implementer this class:
Relation relationship = new Relation(relation1, relation2, relation3
, relation4);
String arrayRelation = relationship.relations();
I lastly included arrayRelation in an array but the array worked fine.
My problem is that the output of the array for my RadioButtons keeps reading "null" (most likey because this code: String relationship = null;). I assume this means that none of my if else statements were satisfied and I really dont know why.
Also important to point out is that if I click submit without clicking any radio button (the button stays on "family"), it reads null. If I click a button once it works perfectly reading the string I intended. But if I click another button afterwards and click submit again, the string goes back to "null".
I know its lengthy but I would really appreciate any help because I am lost.
P.S. some parts of my code are repetitive because I was playing around trying to fix the problem.

I suggest you handle your action events separately, for example:
family.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
familyActionPerformed(evt);
}
});
Then implement familyActionPerformed(evt):
private void familyActionPerformed(java.awt.event.ActionEvent evt) {
// every click on family radio button causes the code here to be executed
relation1 = true;
}
Also write an event handler for the button you click, like this:
submitButtonActionPerformed(java.awt.event.ActionEvent evt) {
// Here test the state of each radio button
relation1 = family.isSelected();
relation2 = friend.isSelected();
relation3 = relative.isSelected();
relation4 = friendFriend.isSelected();
}
MORE EDIT:
Doing what you're doing with NetBeans should be very easy. Here are tutorials that will clear it all up for you:
Tutorial 1
Tutorial 2
I explain the solution again:
Using 'family' button as an example, in your constructor where you have created and initialised your GUI components do this:
JRadioButton family = new JRadioButton();
// do any other thing you want to do to this button and finally..
family.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
familyActionPerformed(evt);
}
});
JButton submit = new JButton("Submit");
submit.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
submitActionPerformed(evt);
}
});
Then somewhere create these methods:
private void familyActionPerformed(java.awt.event.ActionEvent evt){
// each time family is selected, you code processes the lines below:
...
}
private void submiteActionPerformed(java.awt.event.ActionEvent evt){
relation1 = family.isSelected();
relation2 = friend.isSelected();
relation3 = relative.isSelected();
relation4 = friendFriend.isSelected();
}
Do something similar for the rest of the RadioButtons.

I think that you're making things way too complex for yourself. If all you want is the String of the JRadioButton pressed, then use the ButtonGroup to get it for you. It can return the ButtonModel of the selected JRadioButton (if any one was selected), and from that you can extract the actionCommand String, although you'll have to remember to set this when you create your JRadioButton.
For example:
import java.awt.event.ActionEvent;
import javax.swing.*;
#SuppressWarnings("serial")
public class JRadioExample extends JPanel {
private static final String[] RADIO_TITLES = { "Family", "Friend",
"Relative", "Friend or Relative" };
private ButtonGroup btnGrp = new ButtonGroup();
public JRadioExample() {
for (int i = 0; i < RADIO_TITLES.length; i++) {
JRadioButton rBtn = new JRadioButton(RADIO_TITLES[i]);
rBtn.setActionCommand(RADIO_TITLES[i]); // ***** this is what needs to
// be set
btnGrp.add(rBtn);
add(rBtn);
}
add(new JButton(new BtnAction("Get Chosen Selection")));
}
private class BtnAction extends AbstractAction {
public BtnAction(String name) {
super(name);
}
#Override
public void actionPerformed(ActionEvent evt) {
ButtonModel model = btnGrp.getSelection();
if (model != null) {
String actionCommand = model.getActionCommand();
System.out.println("Selected Button: " + actionCommand);
} else {
System.out.println("No Button Selected");
}
}
}
private static void createAndShowGui() {
JRadioExample mainPanel = new JRadioExample();
JFrame frame = new JFrame("JRadioExample");
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();
}
});
}
}