Currently, I have a JList listen to list selection listener.
private void jList1ValueChanged(javax.swing.event.ListSelectionEvent evt) {
// When the user release the mouse button and completes the selection,
// getValueIsAdjusting() becomes false
if (evt.getValueIsAdjusting()) {
/*
In certain situation, I may want to prevent user from selecting other
than current selection. How can I do so?
*/
}
}
In certain situation, I may want to prevent user from selecting other than current selection. How can I do so?
It seems too late when I receive ListSelectionEvent. But, if I want to do it before ListSelectionEvent happen, I do not know that user is trying to select other.
Here is one of the senario.
The JList is contains list of project name.
So, whenever user select new list item, we need to turn the View, from current project, and display new project.
However, current project may be unsaved yet.
Hence, if current project unsaved yet, we will ask for user confirmation, "Save Project?" (Yes, No, Cancel)
When user select cancel, this means he want to cancel his "select to another project" action. He want to stick with current JList selection.
We will pop up the confirmation dialog box in jList1ValueChanged event handle.
But when we try to stick with current JList selection, it is already too late.
I've implemented this as follows for the same workflow use-case. While it works sufficiently for me, I do wish there was a simpler and more elegant approach where the selection event could be vetoed before proceeding. If I have time to investigate and figure that out I'll repost, but it might rank as a case where the return on investment isn't worth it (i.e. customizing Swing classes, handling lower level mouse/keyboard events directly, etc). Anyway what I'm doing currently is saving the last good 'validated' selection, and reverting back to it if the user cancels a future selection. It's admittedly not the prettiest solution, but it works:
// save the last good (i.e. validated) selection:
private ProjectClass lastSelectedProj;
// listing of available projects:
private JList list;
// true if current selected project has been modified without saving:
private boolean dirty;
list.addListSelectionListener(new ListSelectionListener() {
public void valueChanged(ListSelectionEvent evt) {
if (evt.getValueIsAdjusting()) return;
// first validate this selection, and give the user a chance to cancel.
// e.g. if selected project is dirty show save: yes/no/cancel dialog.
if (dirty) {
int choice = JOptionPane.showConfirmDialog(this,
"Save changes?",
"Unsaved changes",
JOptionPane.YES_NO_CANCEL_OPTION,
JOptionPane.WARNING_MESSAGE);
// if the user cancels the selection event revert to previous selection:
if (choice == JOptionPane.CANCEL_OPTION) {
dirty = false; // don't cause yet another prompt when reverting selection
list.setSelectedValue(lastSelectedProj, true);
dirty = true; // restore dirty state. not elegant, but it works.
return;
} else {
// handle YES and NO options
dirty = false;
}
}
// on a validated selection event:
lastSelectedProj = list.getSelectedValue();
// proceed to update views for the newly selected project...
}
}
I think you would need to override the setSelectionInterval(...) method of JList to do nothing under your special situations.
Handling it at the event level is too late as the event has already occured.
I would suggest that you implement a custom ListSelectionModel.
table.setSelectionModel(new DefaultListSelectionModel(){
#Override
public void setSelectionInterval(int index0, int index1) {
if (dragState==0 && index0==index1 && isSelectedIndex(index0)) {
// Deny all clicks that are one row & already selected
return;
} else {
super.setSelectionInterval(index0, index1);
}
}
});
Related
I'm struggling with ZK Framework Combobox UI rendering. I have a combobox with 2 logical lists (1 is a short version of 2, with "Show more" option, and 2 is a list with all entries and no "Show more" option). I've done some list swapping logic tracked by onClick event of "Show more" option. And when I click this option combobox closes and than I need to re-open it to see the full list. So my question is do anyone know a way how to keep combobox opened when I click this specific option (and furthermore, dynamically populate model by another list)? Maybe there are any other best practices of how to do the task more efficiently? Thanks everyone for help
I have a thought about combobox that enables multiple choice — it doesn't close when some option is clicked, but I haven't found any related information. Maybe you could make your suggestions about it
The behavior you want "clicking 'show more' and keep the popup open" is not supported by default.
So you have to override its js widget's doClick_(), please read
https://www.zkoss.org/wiki/ZK_Client-side_Reference/General_Control/Widget_Customization
here is an example.
<zscript><![CDATA[
ListModelList fullModel = new ListModelList(Locale.getAvailableLocales());
ListModelList model1 = new ListModelList(fullModel.subList(0, 2));
model1.add("show more");
]]></zscript>
<combobox id="box" model="${model1}" readonly="true" onSelect="loadAll()"/>
<script src="comboitem-doclick.js"/>
<zscript><![CDATA[
public void loadAll(){
if (model1.getSelection().iterator().next().equals("show more")){
box.setModel(fullModel);
box.setValue("");
}
}
]]></zscript>
/**
* Purpose: when a user selects a specific item, keep the popup open.
* Based on version: 9.6.3
*/
zk.afterLoad('zul.inp', function() {
var exWidget = {};
zk.override(zul.inp.Comboitem.prototype, exWidget, {
doClick_: function doClick_(evt) {
if (!this._disabled) {
var cb = this.parent;
cb._select(this, {
sendOnSelect: true,
sendOnChange: true
});
this._updateHoverImage();
if (this.getLabel() != 'show more'){
cb.close({
sendOnOpen: true,
focus: true
}); // Fixed the onFocus event is triggered too late in IE.
}
cb._shallClose = true;
if (zul.inp.InputCtrl.isPreservedFocus(this)) zk(cb.getInputNode()).focus();
evt.stop();
}
},
});
});
Creating a really basic Memory game using Java Swing. I created my GUI with a list of blank buttons where I set the icon property to none.
My code for some of the buttons is:
private void tbtnCard3ActionPerformed(java.awt.event.ActionEvent evt) {
tbtnCard3.setIcon(new javax.swing.ImageIcon(getClass().getResource("/Card3Logo.png")));
if(tbtnCard5.isSelected()){
score++;
lblScore.setText(""+score);
}
}
private void tbtnCard4ActionPerformed(java.awt.event.ActionEvent evt) {
tbtnCard4.setIcon(new javax.swing.ImageIcon(getClass().getResource("/Card7EWaste.png")));
if(tbtnCard7.isSelected()){
score++;
lblScore.setText(""+score);
}
}
private void tbtnCard5ActionPerformed(java.awt.event.ActionEvent evt) {
tbtnCard5.setIcon(new javax.swing.ImageIcon(getClass().getResource("/Card3Logo.png")));
if(tbtnCard3.isSelected()){
score++;
lblScore.setText(""+score);
}
}
I have about 20 toggle buttons and for example the code above works and the scores go up by 1 when a match is found. So for tbtnCard3, if tbtnCard5 is selected the score goes up by 1. Now my question is how would I make it so that if tbtnCard3 is selected but tbtnCard 5 is not selected, display "Wrong Match". Since im using if Selected I'm not too sure how to display "wrong match" when the case is false. It doesn't make sense to say else ifSelected as no parameters can be put either....
In my opinion, the OPs suggestion is not a good approach. You do not want the listener of one button to be "aware" of some other component unnecessarily. Suppose you have an 8-by-8 grid with toggle buttons. You don't want each toggle button listener to be aware of the other 63 toggle buttons.
I believe there is a much simpler (and cleaner) approach. What you want is for the toggle button listener to register and deregister the toggle when the state of the button changes. Let say, you add the toggle button to or remove from a list (most likely a custom class) where you can trigger some logic when the list size reaches two. Then, depending on the outcome of the comparison, it will count a match (and disable these two toggle buttons in the current state), or will display some message like "Try again" and then toggle the buttons to hide the image.
In pseudocode, this will look something like this:
public class ToggleListener implements ItemListener {
public void actionPerformed (ItemEvent event) {
JToggleButton button = (JToggleButton) event.getSource();
if (event.getStateChange()==ItemEvent.SELECTED) {
// TODO Add the button to your list..
} else {
// remove button
}
}
}
In your Swing application, you can create a single instance of the above listener and add it to every single toggle button. And, as you can see, this listener is only responsible to register and unregister the component associated with the triggered event.
The "List Listener" on the other hand, is responsible to trigger the comparison logic when the size of the list reaches two. So, if you click on the same toggle button over and over again, the only thing the button listener will do is add or remove the button from the list depending on the button's current state. However, once a second button is toggled to reveal its image, the list listener will trigger the comparison logic. I am not 100% sure, but I think you could use JavaFX ObservableList interface or one of its implementing classes to do this. If the ListChangeListener.Change class is not suitable to figure out the size of the list to trigger the logic, you will have to implement this on your own. Regardless, in pseudocode, you need to do something like this:
public void onListChange(Event event) {
if (list.size() == 2 && btn1.getIconName().equals(btn2.getIconName())) {
displayMatchMessage();
btn1.setEnabled(false);
btn2.setEnabled(false);
list.clear(); // you should remove matched items from list manually
} else {
displayMismatchMessage();
btn1.setSelected(false); // flip the card
btn2.setSelected(false); // flip the card
// list.clear(); // you should not need this because the setSelected should trigger the Item Listener which should remove item from list.
}
}
Doing something like this is a much cleaner implementation where the button listener have a single job to do and the "list listener" has another job to do. Neither one encroaches on the other's job.
The problem is that when i click on the surname field when the name field is empty both messages appear because the focus is lost even from surname when the message dialog appears. Is there anything i can do to make the program show the name message and the focus to stay on the name field?
I tried the .requestFocus() but it didn't work.
private void NameFieldFocusLost(java.awt.event.FocusEvent evt) {
if (NameField.getText().equals('smth')) {
JOptionPane.showMessageDialog(null, "Please put a name!","Error!", JOptionPane.INFORMATION_MESSAGE);
}
}
private void SurnameFieldFocusLost(java.awt.event.FocusEvent evt) {
if (SurnameField.getText().equals("smth")) {
JOptionPane.showMessageDialog(null, "Please put a surname!","Error!", JOptionPane.INFORMATION_MESSAGE);
}
}
First off, in the NameFieldFocusLost event: if (NameField.getText().equals('smth')) { doesn't fly. The equals() method requires a String: if (NameField.getText().equals("smth")) { or better yet...since you want to ensure a name is actually provided:
if (NameField.getText().trim().equals("")) {
There must be something we're not being shown. I don't understand why both MessageBoxes would be displaying when focus is taken away from the nameFieldFocusLost event. This shouldn't happen unless you have code somewhere moving focus around especially before your form is actually visible. The requestFocus() method should work as well and should be called directly after you display the MessageBox, for example:
private void nameFieldFocusLost(java.awt.event.FocusEvent evt) {
if (nameField.getText().trim().equals("")) {
JOptionPane.showMessageDialog(this, "Please put a name!","Error!", JOptionPane.INFORMATION_MESSAGE);
nameField.setText(""); // Clear the JTextField in case a white-space was placed there.
nameField.requestFocus(); // Force focus back onto the JTextField.
}
}
If you are moving focus to a JTextField before the parent container is visible (Form / JDialog) then you could possibly experience your particular problem.
EDIT:
Ahhh...I see the problem, thank you for the comment. Here are a few ways you can get around this dilemma:
Add a condition within the focusLost event for the next
JTextField to be in focus which will force an exit of that event
should the validation of the previously focused JTextField fail.
In your case you have a First Name text field and a Last Name text
field. In the focusLost event for the Last Name field you would have
the very first line of code being:
if (nameField.getText().trim().equals("")) { return; }
This way the remaining event code doesn't get run in the Surname
Lost Focus event unless validation for Name field is successful. The
entire Surname event code may look like this:
private void surnameFocusLost(java.awt.event.FocusEvent evt) {
if (nameField.getText().trim().equals("")) { return; }
if (surnameField.getText().trim().equals("")) {
JOptionPane.showMessageDialog(this, "Please put a last name!","Error!", JOptionPane.INFORMATION_MESSAGE);
surnameField.setText(""); // Clear the JTextField in case a white-space was placed there.
surnameField.requestFocus(); // Force focus back onto the JTextField.
}
}
An other way would be to utilize the InputVerifier
Class.
There is good example of its use in this SO
post.
Don't use the JTextField's Focus Events at all. If there is a button
that will be selected to further processing with the inputted data
then check the validation for all your JTextFields there (in the button's actionPerformed event) and force a
focus upon the field that fails (nameField.requestFocus();) for proper input.
Let 'x' be an item in the JList. When I click it for the first time, the event fires, when I click it again, the event does not fire. I have to click some other item and then come back to 'x'.
How can I fire the event repeatedly from 'x' without having to deal with other items.
This is my code:
public void valueChanged(ListSelectionEvent e) {
if (e.getValueIsAdjusting() == false) {
if (list.getSelectedIndex() == -1) {} else {
String clicked = (String)list.getSelectedValue();
//method to fire is here
}
}
updateDisplays();
}
The ListSelectionListener reflects changes to the lists selection, you could use a MouseListener instead...
For example...
MouseListener ml = new MouseAdapter() {
#Override
public void mouseClicked(MouseEvent evt) {
if (SwingUtilities.isLeftMouseButton(evt) && evt.getClickCount() == 1) {
if (list.getSelectedIndex() != -1) {
int index = list.locationToIndex(evt.getPoint());
System.out.println("You clicked item # " + index);
}
}
}
}
list.addMouseListener(ml);
You can add a MouseListener and watch for clicks. Note that a click that changes the selection will fire both the MouseListener and your ListSelectionListener.
Another option is to immediately clear the selection from your ListSelectionListener; that way the next click will reselect and retrigger, although you will lose the ability to navigate through items with the keyboard.
It seems like sort of an unusual UX decision, though, to assign significance to a click on an already selected item in a list.
Adding based on your question comments: If you go the MouseListener route, I recommend looking for double-clicks instead of single-clicks if the click is going to execute an action (especially if the action changes data and is not undoable). Also note that your ListSelectionListener will execute actions as you navigate through the list with the keyboard, which may not be what you intend.
If your commands in your history list are typed, you could also consider using a drop-down combo box for both command entry and the history list, where a selection from history fills in the command text but does not execute. You'd also have an opportunity to add auto-complete from command history.
before I start, I'm a beginner programmer.
How can I enable a text field when a button is clicked.
I have two frames, one that has the JFields and the other for the exception.
When the exception occurs > setEditable(false)
but what statement should I make to enable the JFields once the user click on okay button -that i've made in the exception-?
I've tried to add static boolean to exception frame, and inside the action performed of this class I initialized that boolean to true.
in the other class, I added an if statment, if that boolean is true, then setEditable(true)
-========-
The point of this program, that when the exception occurs the user cannot enter anything in the fields until he closes the exception window.
I wish you'd help me.
With all love, programmers.
The code of action performed for THE EXCEPTION WINDOW FRAME ( having Okay button. )
public void actionPerformed(ActionEvent e){
{
allow=true; //static boolean
Container TheFrame = OKButton.getParent();
do TheFrame = TheFrame.getParent();
while (!(TheFrame instanceof JFrame));
((JFrame) TheFrame).dispose();
}
The code of action performed for THE MAIN PROGRAM (having three fields, an exception will occur once the user enters non digits )
I added some comments to clarify.
public void actionPerformed(ActionEvent event) {
try{
r =Double.parseDouble(RField.getText());
s=Double.parseDouble(SField.getText());
h=Double.parseDouble(HField.getText());
Cone C = new Cone(r,s,h);//class cone
if (event.getSource() instanceof JButton) {
JButton clickedButton = (JButton) event.getSource();
if (clickedButton == VolumeButton) {
Result.append("VOLUME = "+C.volume()+ "\n");
ifV= true;//this's for clearing the fields for new entries.
}
if (clickedButton == AreaButton) {
Result.append("SURFACE AREA = "+C.surfaceArea()+ "\n");
ifA= true;//this's for clearing the fields for new entries.
}
if(ifA&&ifV){ // clearing the fields for new entries.
SField.setText(CLEAR);
HField.setText(CLEAR);
RField.setText(CLEAR);
ifV=false; ifA= false;}
}
SList.addShape(C);
}
catch(NumberFormatException e){
//Object of type "Exception__" already created
Ex.setVisible(true);//class "Exception__" is the one i've made for Exception window
SField.setText(CLEAR);
HField.setText(CLEAR);
RField.setText(CLEAR);
SField.setEditable(false);
HField.setEditable(false);
RField.setEditable(false);
}/*here, if the user clicked on -that okay in Exception window-
and variable allow initialized to "true" those statements should extend. I guess?
- everything worked correctly except for this ?*/
if(Ex.allow){
SField.setEditable(true);
HField.setEditable(true);
RField.setEditable(true); }
}
THANK YOU ALL IT FINALLY WORKED.
I added
Ex.allow(SField,HField,RField);
to the catch.
and added this method in class Exception__:
public void allow(JTextField js,JTextField jh,JTextField jr){
HField =jh;
SField =js;
RField =jr;
}
finally, to the action performed of class Exception__:
SField.setEditable(true);
HField.setEditable(true);
RField.setEditable(true);
WOHOOOO. It feels so awesome lol. Thanks all. should I delete my question or leave it for others who might face the same problem as mine? :P
Your question needs a lot more detail. But if all you want to to show an 'exception window' and allow the user to do anything else only after she dismisses this window, I think all you need is a MessageDialog:
See JOptionPane
If you need more details to be displayed you can create your own modal JDialog.
See How to Make Dialogs
Make the text field hiden by writing:
jTextfield.setVisible(fasle);
in the constructor of your form code. than use the button event " Action -> Action Performed " and write the code:
jTextfield.setVisible(true);
and thus your text field will be visible only after the button will be clicked.