I have a Java Swing application, that has many JTextFields and a datamodel.
When leaving the textfields (focus lost), the text is written to the Model. So far, so good.
There are JMenu-Actions that read data from the model and send it to the server.
The Problem is, that the "focus lost" is not fired when running the Menu Action by it's accelerator. So the Actions reads and transmit the old value from the datamodel. .
There may be many ways to fix this...? Do you have suggestions how to solve this?
What doesn't work for me:
Write to model on every key press (via Document Listener): not usable, should only write on leaving textfield (focus lost). The text is (expensively) evaluated after writing it to the model - can not run after every key press.
Handling the writing to model in every action. There ca. 500 Textfields and ca. 100 actions. Diffucult to match without forgetting anything.
Runnable Demo Code:
package swingmodel;
import java.awt.FlowLayout;
import java.awt.event.*;
import javax.swing.*;
/**
* Simple Demo Problem. Enter a Text in the first Textfield and press ALT-T. The
* focus listener did no run, therefore the old value from model is displayed.
*/
public class TextDemoOnMenu extends JPanel {
private Model model;
public TextDemoOnMenu() {
super(new FlowLayout());
model = new Model();
MyTextField textField = new MyTextField(20, model);
add(textField);
add(new JTextField(5));
}
class MyTextField extends JTextField {
private Model model;
public MyTextField(int arg, Model model) {
super(arg);
this.model = model;
addFocusListener(new FocusAdapter() {
#Override
public void focusLost(FocusEvent e) {
System.out.println("focus lost");
writeToModel();
}
});
}
public void writeToModel() {
this.model.setText(getText());
}
}
class ShowModelTextAction extends AbstractAction {
public ShowModelTextAction(String string) {
super(string);
}
#Override
public void actionPerformed(ActionEvent e) {
String message = "text is: " + model.getText();
JOptionPane.showMessageDialog(TextDemoOnMenu.this, message);
}
}
class Model {
private String text;
void setText(String t) {
text = t;
}
public String getText() {
return text;
}
}
private void createAndShowGUI() {
// Create and set up the window.
JFrame frame = new JFrame("TextDemo");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
// Add contents to the window.
frame.add(this);
Action action = new ShowModelTextAction("show text");
JMenuBar menuBar = new JMenuBar();
JMenu menu = new JMenu("My Menu");
menuBar.add(menu);
JMenuItem menuItem = new JMenuItem("show text");
menuItem.setAction(action);
menuItem.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_T, ActionEvent.ALT_MASK));
menu.add(menuItem);
frame.setJMenuBar(menuBar);
// Display the window.
frame.setSize(400, 200);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
new TextDemoOnMenu().createAndShowGUI();
}
});
}
}
You could modify all your Actions to use the KeyboardFocusManager. You would get the current component that has focus. If it is one of your custom text fields, then you can force an update to the model before processing the Action.
The text is (expensively) evaluated after writing it to the model
Also, it sounds like you should be handling focusGained as well. Then can save the original text and do a comparison on the text on focus lost before automatically updating the model. (ie. what if somebody just tabs through all the text fields?).
Create a dirty flag for each textField. If the save event occurs you can update the model with any textField that is dirty.
If you are worried that you will 'forget' to do this for a particular textField it is your management of the textfields that is the problem. You should have a factory method for them that sets them up correctly and creates dirty flags for them.
My other suggestion is to when that save action occurs you request focus to a hidden component to trigger the focusLost on the textField. When the save is completed you give the focus back to the previous owner.
Related
I'm working on a gui program the allows you to open a JFrame with a txt file and allows you to copy and paste from a JMenu. But for some reason I cannot modify the text area after the txt file is loaded
heres my class with the methods, I have one that generates a JFrame I designed in my MyJFrame class and outputs a string in a scroll pane
the other method where I'm just trying to modify the that text area where the file is. I know this would be a lot easier if it was all in one class but my professor wants me to make this DisplayText method with the copy and paste methods.
public class DisplayText {
public JTextArea text = new JTextArea();
public void displayText(String title, String info)
{
MyJFrame f = new MyJFrame(title);
Container c = f.getContentPane();
c.add(text);
JScrollPane pane = new JScrollPane(text);
c.add(pane);
text.append(info);
f.setVisible(true);
}
public void selectText()
{
text.append("THIS IS A TEST");
}
public void insertText()
{
text.paste();
}
}
heres the code where I put the action listener for the copy menu item, its in the MyJFrame class
item8.addActionListener(new ActionListener() //copy menu item
{
public void actionPerformed(ActionEvent e)
{
dt.selectText();
}
});
the copy button in the menu does not work at all and I'm not sure why, could you guys help me out? Thanks!!
I'm working on a game which consists entirely of menus/screens which you interact with using buttons, essentially a text-based game but without the typing. To do this I have been working with Swing to create a basic UI, following this video series.
In order to have actions performed in one panel affect the state of another, I have followed the tutorial and created a UIListener interface, which extends EventListener. When a button is pressed in one JPanel, the fireUIEvent method of the panel is called, which in turn calls the sole method of the interface, uiEventOccurred, which is implemented in an anonymous class inside the main JFrame class. Then the JFrame can do whatever it wants with the event, and modify other JPanels it contains accordingly.
For example, I have a panel that represents the town. It has a button you click to travel to the dungeon. When this button is clicked, the town panel is replaced by the dungeon panel, which has a button you can click to return to the town.
I'll post the relevant classes:
the main frame class
public class GameMainFrame extends JFrame{
public JPanel rightPanel;
public GameMainFrame(String title) {
super(title);
/* Setting The Overall Layout */
setLayout(new BorderLayout());
/* Creating Individual UI Panels */
UIPanel uip_town = new Town_UI();
UIPanel uip_dung = new Dungeon_UI();
/* Creating A Nested Panel */
rightPanel = new JPanel();
rightPanel.setLayout(new BorderLayout());
rightPanel.add(uip_text, BorderLayout.WEST);
rightPanel.add(uip_town, BorderLayout.NORTH);
/* Creating A Listener To React To Events From The UI Panels */
uip_town.addUIListener(new UIListener() {
public void uiEventOccurred(UIEvent event) {
System.out.println("event text: " + event.getText());
if (event.getText().equals("goto_dungeon")) {
rightPanel.remove(uip_town);
rightPanel.add(uip_dung, BorderLayout.NORTH);
validate();
} else if (event.getText().equals("goto_town")) {
rightPanel.remove(uip_dung);
rightPanel.add(uip_town, BorderLayout.NORTH);
validate();
}
}
});
/* Adding Panels To The Content Pane Of The Frame */
Container c = getContentPane();
c.add(uip_info, BorderLayout.WEST);
c.add(rightPanel, BorderLayout.CENTER);
}
}
UIPanel class
public class UIPanel extends JPanel {
private EventListenerList listenerList;
public UIPanel() {
listenerList = new EventListenerList();
}
public void fireUIEvent(UIEvent event) {
Object[] listeners = listenerList.getListenerList();
for (int i = 0; i < listeners.length; i += 2) {
if (listeners[i] == UIListener.class) {
((UIListener) listeners[i + 1]).uiEventOccurred(event);
}
}
}
public void addUIListener(UIListener listener) {
listenerList.add(UIListener.class, listener);
}
public void removeUIListener(UIListener listener) {
listenerList.remove(UIListener.class, listener);
}
}
Town_UI class
public class Town_UI extends UIPanel {
public Town_UI() {
Dimension size = getPreferredSize();
size.height = 466;
setPreferredSize(size);
setBorder(BorderFactory.createTitledBorder("Town"));
JButton btn_dungeon_enter = new JButton("Enter the dungeon");
add(btn_dungeon_enter);
btn_dungeon_enter.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
fireUIEvent(new UIEvent(this, "goto_dungeon"));
}
});
}
}
Dungeon_UI class
public class Dungeon_UI extends UIPanel {
public Dungeon_UI() {
Dimension size = getPreferredSize();
size.height = 466;
setPreferredSize(size);
setBorder(BorderFactory.createTitledBorder("Dungeon"));
JButton btn_town_return = new JButton("Return to town");
add(btn_town_return);
btn_town_return.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
fireUIEvent(new UIEvent(this, "goto_town"));
}
});
}
}
UIEvent object
public class UIEvent extends EventObject {
private String text;
public UIEvent(Object source, String text) {
super(source);
this.text = text;
}
public String getText() {
return text;
}
}
UIListener interface
public interface UIListener extends EventListener {
public void uiEventOccurred(UIEvent e);
}
I have two problems with this. Number one, it is currently bugged. When I run the application, the Town_UI panel appears with its button "Enter the dungeon", and upon clicking on it the frame correctly updates, replacing the Town_UI panel with the Dungeon_UI panel. However, clicking on the "Return to town" button on the dungeon panel doesn't do anything. When trying to debug this I found that the cause was in the UIPanel method fireUIEvent. When the "Return to town" button is pressed, this method is correctly called, but when it creates the Object array using getListenerList, the array is empty, so it skips the for-loop and no action is performed. Because I am unfamiliar with ActionEvents and EventListeners in Java, though, I am not sure how to fix this.
My other problem is that all of the behaviors that occur when a button is pressed are handled in the anonymous class in the GameMainFrame class. This means that if I want to have a bunch of different buttons all do different things (which I do plan on implementing), I'll need a whole bunch of conditionals in the anonymous class to determine what button is pressed and perform the corresponding behavior. I feel like it would be a lot cleaner if the button behavior could be implemented in the anonymous ActionListener class of each button, but I'm not sure how I should restructure my code so that I can do this but also allow any action on any panel able modify any other panel.
In the tutorial I watched he claimed that this implementation of EventListeners was what you should do in order to avoid making your code a rat's nest, but it seems like that is where my code is heading if I use this implementation for what I am trying to do.
I'm curious how can I use a dialog designer that is built into IntelliJ IDEA since I find it an option with big potential but I don't really know how to use it.
Let's consider a desktop program with two classes created using designer: MainWindow and MainDialog. Let's assume that MainWindow class already has all fields, components etc. required for a simple form to be displayed. Then in the MainWindow class we have:
JLabel label = new JLabel("This is default text");
JButton showDialog = new JButton("Show dialog");
showDialog.addActionListener(new ActionListener()
{
#Override
public void actionPerformed(ActionEvent e)
{
MainDialog dialog = new MainDialog ();
dialog.pack();
dialog.setVisible(true);
}
});
which makes the dialog visible. The MainDialog class designed by default by designer looks like this:
public class MainDialog extends JDialog {
private JPanel contentPane;
private JButton buttonOK;
private JButton buttonCancel;
public MainDialog() {
setContentPane(contentPane);
setModal(true);
getRootPane().setDefaultButton(buttonOK);
buttonOK.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
onOK();
}
});
buttonCancel.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
onCancel();
}
});
// call onCancel() when cross is clicked
setDefaultCloseOperation(DO_NOTHING_ON_CLOSE);
addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
onCancel();
}
});
// call onCancel() on ESCAPE
contentPane.registerKeyboardAction(new ActionListener() {
public void actionPerformed(ActionEvent e) {
onCancel();
}
}, KeyStroke.getKeyStroke(KeyEvent.VK_ESCAPE, 0), JComponent.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT);
}
private void onOK() {
// add your code here
dispose();
}
private void onCancel() {
// add your code here if necessary
dispose();
}
}
Now let's also assume that in the dialog class I have a text field:
JTextField textField = new JTextField();
that I am getting a text to be displayed by label in the MainWindow class from.
Since I have an onOK() function created by default I'd like it to update a label in MainWindow class with text typed in text field in MainDialog class.
The problem is: how can I perform an action on another class's field using this pattern without writing in MainDialog a line MainWindow window = new MainWindow or making label static? Is it possible? I know that this can be done much simpler but this is also an easy example and I'd like to perform much more complex operations using this structure.
Yes, it's possible.
First option: since the dialog is modal, the code opening the modal in the main window will be blocked until the dialog is closed. So you could just do something like this in the modal:
public String getEnteredText() {
return textField.getText();
}
and in the main window:
dialog.setVisible(true);
myLabel.setText(dialog.getEnteredText());
Or (but I would use the first option), you can pass the main window, or any other callback, to the dialog. For example:
MainDialog dialog = new MainDialog(this);
And in the dialog:
private void onOK() {
mainWindow.setLabelText(textField.getText());
dispose();
}
My recommendation is to avoid UI designers. Especially if you're not able yet to write the code that they generate by yourself, and you don't have a deep understanding of how Swing works.
I have two Jframes where frame1 has some text fields and when a button on frame1 is clicked, I open another JFrame which contains a search box and a JTable containing search results.
When I click on a result row on JTable, I want that particular values to be reflected in the frame1 text fields.
I tried passing the JFrame1's object as a parameter but I have no clear idea on how to achieve this.
Any help would be highly appreciated.
Thanks
First of all, your program design seems a bit off, as if you are using a JFrame for one of your windows where you should in fact be using a JDialog since it sounds as if one window should be dependent upon the other.
But regardless, you pass references of GUI objects the same as you would standard non-GUI Java code. If one window opens the other (the second often being the dialog), then the first window usually already holds a reference to the second window and can call methods off of it. The key often is when to have the first window call the second's methods to get its state. If the second is a modal dialog, then the when is easy -- immediately after the dialog returns which will be in the code immediately after you set the second dialog visible. If it is not a modal dialog, then you probably want to use a listener of some sort to know when to extract the information.
Having said this, the details will all depend on your program structure, and you'll need to tell us more about this if you want more specific help.
For a simple example that has one window open another, allows the user to enter text into the dialog windows JTextField, and then places the text in the first window's JTextField, please have a look at this:
import java.awt.Window;
import java.awt.Dialog.ModalityType;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;
public class WindowCommunication {
private static void createAndShowUI() {
JFrame frame = new JFrame("WindowCommunication");
frame.getContentPane().add(new MyFramePanel());
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
// let's be sure to start Swing on the Swing event thread
public static void main(String[] args) {
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
createAndShowUI();
}
});
}
}
class MyFramePanel extends JPanel {
private JTextField field = new JTextField(10);
private JButton openDialogeBtn = new JButton("Open Dialog");
// here my main gui has a reference to the JDialog and to the
// MyDialogPanel which is displayed in the JDialog
private MyDialogPanel dialogPanel = new MyDialogPanel();
private JDialog dialog;
public MyFramePanel() {
openDialogeBtn.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
openTableAction();
}
});
field.setEditable(false);
field.setFocusable(false);
add(field);
add(openDialogeBtn);
}
private void openTableAction() {
// lazy creation of the JDialog
if (dialog == null) {
Window win = SwingUtilities.getWindowAncestor(this);
if (win != null) {
dialog = new JDialog(win, "My Dialog",
ModalityType.APPLICATION_MODAL);
dialog.getContentPane().add(dialogPanel);
dialog.pack();
dialog.setLocationRelativeTo(null);
}
}
dialog.setVisible(true); // here the modal dialog takes over
// this line starts *after* the modal dialog has been disposed
// **** here's the key where I get the String from JTextField in the GUI held
// by the JDialog and put it into this GUI's JTextField.
field.setText(dialogPanel.getFieldText());
}
}
class MyDialogPanel extends JPanel {
private JTextField field = new JTextField(10);
private JButton okButton = new JButton("OK");
public MyDialogPanel() {
okButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
okButtonAction();
}
});
add(field);
add(okButton);
}
// to allow outside classes to get the text held by the JTextField
public String getFieldText() {
return field.getText();
}
// This button's action is simply to dispose of the JDialog.
private void okButtonAction() {
// win is here the JDialog that holds this JPanel, but it could be a JFrame or
// any other top-level container that is holding this JPanel
Window win = SwingUtilities.getWindowAncestor(this);
if (win != null) {
win.dispose();
}
}
}
You'd do a very similar technique to get information out of a JTable.
And again, if this information doesn't help you, then please tell us more about your program including showing us some of your code. The best code to show is a small compilable example, an SSCCE similar to what I've posted above.
In my program I have a main JFrame that holds a button. When this button is clicked a new JFrame appears in which I can change some information. Whenever I finish editing I press a save button on the new JFrame which saves the changes and disposes the JFrame. Now when this is done, I'd like to perform an action in the main JFrame as well, but only if something changed. If I open the new JFrame and just close it again without using the save button, I don't want to do anything in the main frame.
I've tried searching the web for a solution, but just don't seem to be anything useful out there..
An example of the code I've got so far:
Main Frame...
public class MainFrame extends JFrame
{
public MainFrame()
{
super("Main Frame");
JButton details = new JButton("Add Detail");
add(details);
details.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e)
{
new DetailFrame().setVisible(true);
}
});
}
}
Detail Frame...
public class DetailFrame extends JFrame
{
public DetailFrame()
{
super("Detail Frame");
JButton save = new JButton("Save");
add(save);
save.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e)
{
// Save whatever content
dispose();
}
});
}
}
So when I click the "Save" button on the Detail Frame, I want to do something in the Main Frame, whereas when the "x" is clicked on the Detail Frame, I don't want to do anything..
Hope someone is able to help me, and sorry for my english..
You can pass a MainFrame handle to the DetailFrame constructor. Then, on clicking the Save button, the DetailFrame would call a function in MainFrame and pass the changes to it.
Another way is to create a public boolean variable in DetailFrame and set it to true when the Save button is clicked. This way MainFrame will know whether the DetailFrame was closed or Save'd.
EDIT: Some more ideas:
Use JDialog instead of JFrame. JDialog.setVisible is modal, i.e. it will block the calling function until the dialog is closed; this way you can process the results of the dialog in the same "Details" button listener.
To access the dialog after it is called, store the dialog in a separate variable. First construct the dialog, then show it, and then process the result by analyzing its variables.
Store the results of editing in other public variables of DetailFrame (or let's call it DetailDialog). This should happen only when the "Save" button is clicked. This may even allow to go without the boolean variable (depends on the types of values you are editing).
DetailDialog dlg = new DetailDialog();
dlg.setVisible(true);
if(dlg.approvedResult != null) {
// process the result...
}
EDIT: Sorry, JDialog is not modal by default. Need to call a special super constructor to make it modal.
Also, here you will have to pass the reference to MainFrame to the dialog constructor, but you still can declare it as a simple JFrame and avoid unnecessary dependencies.
To get the reference to the enclosing MainFrame from within the anonymous ActionListener, use MainFrame.this.
To be able to change the button text after it was created, you will have to store the button in a member variable.
Main Frame...
public class MainFrame extends JFrame
{
private JButton details = new JButton("Add Detail");
public MainFrame()
{
super("Main Frame");
getContentPane().add(details);
details.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e)
{
DetailDialog dlg = new DetailDialog(MainFrame.this);
dlg.setVisible(true);
if(dlg.approved){
details.setText("Edit Detail");
}
}
});
}
}
Detail Dialog... (not Frame)
public class DetailDialog extends JDialog
{
public boolean approved = false;
public DetailDialog(JFrame parent)
{
super(parent,"Detail Dialog",true); // modal dialog parented to the calling frame
JButton save = new JButton("Save");
getContentPane().add(save);
save.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e)
{
// Save whatever content
approved = true;
dispose();
}
});
}
}
Create the detail frame in the main frame, and add a windowlistener to it, using the windowadapter class. Implement the windowclosing event by checking for changes, handle those, and then dispose the detail frame. This is all done in the mainframe.
The detail frame should have do nothing on close set to prevent the detail frame being disposed before you recorded the changes.
You may wish to implement checking for changes in the detailframe as a method returning a class holding the interesting data. That way your windowlistener can be small an to the point.
Forget the 2nd JFrame. use a modal dialog instead. It will block input until dismissed. Once dismissed, the only thing to do is decide whether to update the original data. JOptionPane has some inbuilt functionality that makes that easy. If the user presses Cancel or the esc key, the showInputDialog() method will return null as the result.
import java.awt.BorderLayout;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.border.EmptyBorder;
class EditInfo {
public static void main(String[] args) {
Runnable r = new Runnable() {
public void run() {
final JFrame f = new JFrame("Uneditable");
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel p = new JPanel(new BorderLayout(10,10));
final JTextField tf = new JTextField("Hello World!", 20);
tf.setEnabled(false);
p.add(tf, BorderLayout.CENTER);
JButton edit = new JButton("Edit");
edit.addActionListener( new ActionListener(){
public void actionPerformed(ActionEvent ae) {
String result = JOptionPane.showInputDialog(
f,
"Edit text",
tf.getText());
if (result!=null) {
tf.setText(result);
}
}
} );
p.add(edit, BorderLayout.EAST);
p.setBorder(new EmptyBorder(10,10,10,10));
f.setContentPane(p);
f.pack();
f.setLocationByPlatform(true);
f.setVisible(true);
}
};
SwingUtilities.invokeLater(r);
}
}
If it is necessary to edit a number of fields all at once in the JOptionPane, use a JPanel to contain them all, and put them in a showMessageDialog() call. Check the integer based return result to determine if the user OK'd the changes.