A typical way to use JFileChooser includes checking whether user clicked OK, like in this code:
private void addModelButtonMouseClicked(java.awt.event.MouseEvent evt) {
JFileChooser modelChooser = new JFileChooser();
if(modelChooser.showOpenDialog(this) == JFileChooser.APPROVE_OPTION ){
File selectedFile = modelChooser.getSelectedFile();
if(verifyModelFile(selectedFile)){
MetModel newModel;
newModel = parser.parse(selectedFile, editedCollection.getDirectory() );
this.editedCollection.addModel(newModel);
this.modelListUpdate();
}
}
}
I tried to mimic this behavior in my own window inheriting JFrame. I thought that this way of handling forms is more convenient than passing collection that is to be edited to the new form. But I have realized that if I want to have a method in my JFrame returning something like exit status of it I need to make it wait for user clicking OK or Cancel without freezing the form/dialog window.
So, how does showOpenDialog() work? When I tried to inspect the implementation, I found only one line methods with note "Compiled code".
I tried to mimic this behavior in my own window inheriting JFrame.
JFrame is not a modal or 'blocking' component. Use a modal JDialog or JOptionPane instead.
E.G.
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.border.*;
/** Typical output:
[JTree, colors, violet]
User cancelled
[JTree, food, bananas]
Press any key to continue . . .
*/
class ConfirmDialog extends JDialog {
public static final int OK_OPTION = 0;
public static final int CANCEL_OPTION = 1;
private int result = -1;
JPanel content;
public ConfirmDialog(Frame parent) {
super(parent,true);
JPanel gui = new JPanel(new BorderLayout(3,3));
gui.setBorder(new EmptyBorder(5,5,5,5));
content = new JPanel(new BorderLayout());
gui.add(content, BorderLayout.CENTER);
JPanel buttons = new JPanel(new FlowLayout(4));
gui.add(buttons, BorderLayout.SOUTH);
JButton ok = new JButton("OK");
buttons.add(ok);
ok.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent ae) {
result = OK_OPTION;
setVisible(false);
}
});
JButton cancel = new JButton("Cancel");
buttons.add(cancel);
cancel.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent ae) {
result = CANCEL_OPTION;
setVisible(false);
}
});
setContentPane(gui);
}
public int showConfirmDialog(JComponent child, String title) {
setTitle(title);
content.removeAll();
content.add(child, BorderLayout.CENTER);
pack();
setLocationRelativeTo(getParent());
setVisible(true);
return result;
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
JFrame f = new JFrame("Test ConfirmDialog");
final ConfirmDialog dialog = new ConfirmDialog(f);
final JTree tree = new JTree();
tree.setVisibleRowCount(5);
final JScrollPane treeScroll = new JScrollPane(tree);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JButton b = new JButton("Choose Tree Item");
b.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent ae) {
int result = dialog.showConfirmDialog(
treeScroll, "Choose an item");
if (result==ConfirmDialog.OK_OPTION) {
System.out.println(tree.getSelectionPath());
} else {
System.out.println("User cancelled");
}
}
});
JPanel p = new JPanel(new BorderLayout());
p.add(b);
p.setBorder(new EmptyBorder(50,50,50,50));
f.setContentPane(p);
f.pack();
f.setLocationByPlatform(true);
f.setVisible(true);
}
});
}
}
I guess you wait for the user to click some button by constantly checking what button is pressed.
"I need to make it wait for user clicking OK or Cancel without freezing the form/dialog window."
May be you should use evens to get notified, when the user clicks on something, not waiting for them to press the button - maybe there is some OnWindowExit event?
Or maybe something like this:
MyPanel panel = new MyPanel(...);
int answer = JOptionPane.showConfirmDialog(
parentComponent, panel, title, JOptionPane.YES_NO_CANCEL,
JOptionPane.PLAIN_MESSAGE );
if (answer == JOptionPane.YES_OPTION)
{
// do stuff with the panel
}
Otherwise you might see how to handle window events, especially windowClosing(WindowEvent) here
Related
Having an issue with some bits of my code.
label1.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent ae) {
label1.setText(-Here i want the button to open up a new "update window, and it will update the label to the text i'll provide in a seperate window);
}
});
Is there any way to do it without without an additional form? Just wanted to add that i have several labels, and i'm not sure on how to start with it.
One approach is to return a result from your update dialog which you can then use to update the text in label1. Here's an example which updates the label text based on the result return from a JOptionPane
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
public class Test {
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
JFrame frame = new JFrame();
frame.setMinimumSize(new Dimension(200, 85));
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new FlowLayout());
JLabel label = new JLabel("Original Text");
frame.add(label);
JButton button = new JButton("Click Me");
frame.add(button);
// to demonstrate, a JOptionPane will be used, but this could be replaced with a custom dialog or other control
button.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
int result = JOptionPane.showConfirmDialog(frame, "Should I update the label?", "Test", JOptionPane.OK_CANCEL_OPTION );
// if the user selected 'Ok' then updated the label text
if(result == JOptionPane.OK_OPTION) {
label.setText("Updated text");
}
}
});
frame.setVisible(true);
}
});
}
}
Another approach would be to use an Observer and Observable which would listen for updates and change the label text accordingly. For more on the Observer, take a look at this question: When should we use Observer and Observable
I already have a pretty basic Java Swing program but realised that I could do with a simple Username/password login screen to restrict access to it to only people with the username and password.
Is there anyway that I can insert some code to the start of the main method which will prevent execution beyond it until the username and password are entered on a screen that appears?
Here is an example of a Login Dialog. Closes entire program with close of Dialog.
Username: stackoverflow Password: stackoverflow
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class TestFrame extends JFrame {
private PassWordDialog passDialog;
public TestFrame() {
passDialog = new PassWordDialog(this, true);
passDialog.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
JFrame frame = new TestFrame();
frame.getContentPane().setBackground(Color.BLACK);
frame.setTitle("Logged In");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLocationRelativeTo(null);
frame.setExtendedState(JFrame.MAXIMIZED_BOTH);
}
});
}
}
class PassWordDialog extends JDialog {
private final JLabel jlblUsername = new JLabel("Username");
private final JLabel jlblPassword = new JLabel("Password");
private final JTextField jtfUsername = new JTextField(15);
private final JPasswordField jpfPassword = new JPasswordField();
private final JButton jbtOk = new JButton("Login");
private final JButton jbtCancel = new JButton("Cancel");
private final JLabel jlblStatus = new JLabel(" ");
public PassWordDialog() {
this(null, true);
}
public PassWordDialog(final JFrame parent, boolean modal) {
super(parent, modal);
JPanel p3 = new JPanel(new GridLayout(2, 1));
p3.add(jlblUsername);
p3.add(jlblPassword);
JPanel p4 = new JPanel(new GridLayout(2, 1));
p4.add(jtfUsername);
p4.add(jpfPassword);
JPanel p1 = new JPanel();
p1.add(p3);
p1.add(p4);
JPanel p2 = new JPanel();
p2.add(jbtOk);
p2.add(jbtCancel);
JPanel p5 = new JPanel(new BorderLayout());
p5.add(p2, BorderLayout.CENTER);
p5.add(jlblStatus, BorderLayout.NORTH);
jlblStatus.setForeground(Color.RED);
jlblStatus.setHorizontalAlignment(SwingConstants.CENTER);
setLayout(new BorderLayout());
add(p1, BorderLayout.CENTER);
add(p5, BorderLayout.SOUTH);
pack();
setLocationRelativeTo(null);
setDefaultCloseOperation(DISPOSE_ON_CLOSE);
addWindowListener(new WindowAdapter() {
#Override
public void windowClosing(WindowEvent e) {
System.exit(0);
}
});
jbtOk.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
if ("stackoverflow".equals(String.valueOf(jpfPassword.getPassword()))
&& "stackoverflow".equals(jtfUsername.getText())) {
parent.setVisible(true);
setVisible(false);
} else {
jlblStatus.setText("Invalid username or password");
}
}
});
jbtCancel.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
setVisible(false);
parent.dispose();
System.exit(0);
}
});
}
}
This is very tricky to do (as you probably realize), to ensure that someone can't sidestep your authentication.
If you don't care too much if someone can get past it, then an easy way to accomplish what you're trying would be to create a variable tracking login process and don't allow your main thread to start the GUI thread of the main application until the authentication is completed. Something like this would work:
public class MyApp {
private static boolean isAuthenticated;
public static void main( String args[] ) {
isAuthenticated = false;
while( !isAuthenicated ) {
authenticateUser();
try{ Thread.sleep( 200 ); } catch( InterruptedException ie ){ }
}
new JFrame();
// finish rest of GUI code.
}
private static void authenticateUser(){
dialog = new MyAuthenticationDialog();
dialog.show();
if( isValid( dialog.getUsername(), dialog.getPassword() )
isAuthenticated = true;
else
isAuthenticated = false;
}
}
If you care whether this can be reverse engineered however (this example would be trivial for me to RE), then you will need to have some encrypted value that uses the correct username and password as a key. Hash these together into a SHA-256 key and encrypt the value. Note that an RE could still bypass this but it will take more effort, especially if you repeatedly check that you can decrypt the value with the user provided credentials in random spots all through your code. Don't use a single function for it otherwise the RE need only patch that one function and his job is easy. At the end of the day you don't have control over the client so no solution will be perfect. These are some ideas. Also run your final code through a Java obfuscator.
You can use a DialogBox with Swing as soon as you execute your main method. Then, based on the code, you can validate. If the values entered are ok with the authentication data (incoming from db, files, etc), then you show your main UI, if not, maybe you can show a dialog with something like "Try again" or close the dialog.
http://java.about.com/od/UsingDialogBoxes/a/How-To-Make-A-Password-Dialog-Box.htm
Hope it helps, best regards.
I have created a frame in Java which has some textfields and buttons in it. Assuming that user wants more textfields (for example to add more data), I want to put a button and when a user clicks the button, then a new textfield should appear. then user can fill data in it and again by clicking that button another textfield should appear.
How can I do this ? What code I need to write for the button to show more and more text fields by clicking button?
Thank you !
It would be wise that instead of adding components to your JFrame directly, you add them to a JPanel. Though related to your problem, have a look at this small example, hopefully might be able to give you some hint, else ask me what is out of bounds.
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class JFrameExample
{
private JFrame frame;
private JButton button;
private JTextField tfield;
private String nameTField;
private int count;
public JFrameExample()
{
nameTField = "tField";
count = 0;
}
private void displayGUI()
{
frame = new JFrame("JFrame Example");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new GridLayout(0, 1, 2, 2));
button = new JButton("Add JTextField");
button.addActionListener(new ActionListener()
{
#Override
public void actionPerformed(ActionEvent ae)
{
tfield = new JTextField();
tfield.setName(nameTField + count);
count++;
frame.add(tfield);
frame.revalidate(); // For JDK 1.7 or above.
//frame.getContentPane().revalidate(); // For JDK 1.6 or below.
frame.repaint();
}
});
frame.add(button);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String... args)
{
SwingUtilities.invokeLater(new Runnable()
{
#Override
public void run()
{
new JFrameExample().displayGUI();
}
});
}
}
Supposing that you have a main container called panel and a button variable button which is already added to panel, you can do:
// handle the button action event
button.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
// create the new text field
JTextField newTextField = new JTextField();
// add it to the container
panel.add(newTextField);
panel.validate();
panel.repaint();
}
});
When adding the new text field, you may need to mention some layout related characteristics, depending on the layout manager you are using (for instance if you use GridBagLayout, you will need to specify the constraints).
I create a Popup using the PopupFactory.getPopup method. According to the documentation, I am required to call the hide() method on the popup when it is no longer needed.
In my application, the popup is the child of a JLabel which may be removed from the current frame in a number of different situations. (Either the JLabel itself or one of its parent containers is removed.) Rather that calling hide() in every single place (and making the Popup object available in all these places) I would prefer to be able to detect the removal of the JLabel or one of its parent containers.
How can I detect the removal? I naively assumed that the removal of a component meant the removal/hiding of its children, but as the code below shows, the popup survives the removal of the JLabel.
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class Xyzzy extends JFrame {
static Xyzzy frame;
static JPanel panel;
static JLabel text1;
static JLabel text2;
public static void main(String[] args) {
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
frame = new Xyzzy();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().setLayout(new BoxLayout(frame.getContentPane(), BoxLayout.PAGE_AXIS));
panel = new JPanel();
panel.setLayout(new BoxLayout(panel, BoxLayout.LINE_AXIS));
frame.add(panel);
text1 = new JLabel("text1");
text2 = new JLabel("text2");
panel.add(text1);
frame.add(new JButton(new AbstractAction("Add popup") {
public void actionPerformed(ActionEvent e) {
PopupFactory factory = PopupFactory.getSharedInstance();
Popup popup = factory.getPopup(text1, new JLabel("POPUP"),frame.getX()+300,frame.getY()+300);
popup.show();
}
}));
frame.add(new JButton(new AbstractAction("New label") {
public void actionPerformed(ActionEvent e) {
panel.remove(text1);
panel.add(text2);
panel.revalidate();
}
}));
frame.setSize(600, 600);
frame.setVisible(true);
}
});
}
}
This code creates a JFrame displaying the text "text1" and two buttons. If you press the button labeled "Add popup", a Popup with the text "POPUP" appears in the window. This Popup is a child of text1. Press the "New label" button and "text1" is removed from the display, but the Popup survives.
I need to be able to detect when text1 or the containing panel is removed so that I can hide the popup. I want to avoid adding code where the actual remove() method is called.
You can use HierarchyListener:
public void actionPerformed(ActionEvent e) {
PopupFactory factory = PopupFactory.getSharedInstance();
final Popup popup = factory.getPopup(text1, new JLabel("POPUP"),frame.getX()+300,frame.getY()+300);
text1.addHierarchyListener(new HierarchyListener() {
public void hierarchyChanged(HierarchyEvent e) {
if (e.getID() == HierarchyEvent.HIERARCHY_CHANGED
&& (e.getChangeFlags() & HierarchyEvent.SHOWING_CHANGED) != 0) {
popup.hide();
}
}
});
popup.show();
}
I have main application where is table with values. Then, I click "Add" button, new CUSTOM (I made it myself) JDialog type popup comes up. There I can input value, make some ticks and click "Confirm". So I need to read that input from dialog, so I can add this value to table in main application.
How can I listen when "confirm" button is pressed, so I can read that value after that?
addISDialog = new AddISDialog();
addISDialog.setVisible(true);
addISDialog.setLocationRelativeTo(null);
//somekind of listener...
//after "Confirm" button in dialog was pressed, get value
value = addISDialog.ISName;
If the dialog will disappear after the user presses confirm:
and you wish to have the dialog behave as a modal JDialog, then it's easy, since you know where in the code your program will be as soon as the user is done dealing with the dialog -- it will be right after you call setVisible(true) on the dialog. So you simply query the dialog object for its state in the lines of code immediately after you call setVisible(true) on the dialog.
If you need to deal with a non-modal dialog, then you'll need to add a WindowListener to the dialog to be notified when the dialog's window has become invisible.
If the dialog is to stay open after the user presses confirm:
Then you should probably use a PropertyChangeListener as has been suggested above. Either that or give the dialog object a public method that allows outside classes the ability to add an ActionListener to the confirm button.
For more detail, please show us relevant bits of your code, or even better, an sscce.
For example to allow the JDialog class to accept outside listeners, you could give it a JTextField and a JButton:
class MyDialog extends JDialog {
private JTextField textfield = new JTextField(10);
private JButton confirmBtn = new JButton("Confirm");
and a method that allows outside classes to add an ActionListener to the button:
public void addConfirmListener(ActionListener listener) {
confirmBtn.addActionListener(listener);
}
Then an outside class can simply call the `addConfirmListener(...) method to add its ActionListener to the confirmBtn.
For example:
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;
public class OutsideListener extends JFrame {
private JTextField textField = new JTextField(10);
private JButton showDialogBtn = new JButton("Show Dialog");
private MyDialog myDialog = new MyDialog(this, "My Dialog");
public OutsideListener(String title) {
super(title);
textField.setEditable(false);
showDialogBtn.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
if (!myDialog.isVisible()) {
myDialog.setVisible(true);
}
}
});
// !! add a listener to the dialog's button
myDialog.addConfirmListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
String text = myDialog.getTextFieldText();
textField.setText(text);
}
});
JPanel panel = new JPanel();
panel.add(textField);
panel.add(showDialogBtn);
add(panel);
}
#Override
public Dimension getPreferredSize() {
return new Dimension(400, 300);
}
private static void createAndShowGui() {
JFrame frame = new OutsideListener("OutsideListener");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
class MyDialog extends JDialog {
private JTextField textfield = new JTextField(10);
private JButton confirmBtn = new JButton("Confirm");
public MyDialog(JFrame frame, String title) {
super(frame, title, false);
JPanel panel = new JPanel();
panel.add(textfield);
panel.add(confirmBtn);
add(panel);
pack();
setLocationRelativeTo(frame);
}
public String getTextFieldText() {
return textfield.getText();
}
public void addConfirmListener(ActionListener listener) {
confirmBtn.addActionListener(listener);
}
}
Caveats though: I don't recommend subclassing JFrame or JDialog unless absolutely necessary. It was done here simply for the sake of brevity. I also myself prefer to use a modal dialog for solving this problem and just re-opening the dialog when needed.
Edit 2
An example of use of a Modal dialog:
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;
public class OutsideListener2 extends JFrame {
private JTextField textField = new JTextField(10);
private JButton showDialogBtn = new JButton("Show Dialog");
private MyDialog2 myDialog = new MyDialog2(this, "My Dialog");
public OutsideListener2(String title) {
super(title);
textField.setEditable(false);
showDialogBtn.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
if (!myDialog.isVisible()) {
myDialog.setVisible(true);
textField.setText(myDialog.getTextFieldText());
}
}
});
JPanel panel = new JPanel();
panel.add(textField);
panel.add(showDialogBtn);
add(panel);
}
#Override
public Dimension getPreferredSize() {
return new Dimension(400, 300);
}
private static void createAndShowGui() {
JFrame frame = new OutsideListener2("OutsideListener");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
class MyDialog2 extends JDialog {
private JTextField textfield = new JTextField(10);
private JButton confirmBtn = new JButton("Confirm");
public MyDialog2(JFrame frame, String title) {
super(frame, title, true); // !!!!! made into a modal dialog
JPanel panel = new JPanel();
panel.add(new JLabel("Please enter a number between 1 and 100:"));
panel.add(textfield);
panel.add(confirmBtn);
add(panel);
pack();
setLocationRelativeTo(frame);
ActionListener confirmListener = new ConfirmListener();
confirmBtn.addActionListener(confirmListener); // add listener
textfield.addActionListener(confirmListener );
}
public String getTextFieldText() {
return textfield.getText();
}
private class ConfirmListener implements ActionListener {
public void actionPerformed(ActionEvent e) {
String text = textfield.getText();
if (isTextValid(text)) {
MyDialog2.this.setVisible(false);
} else {
// show warning
String warning = "Data entered, \"" + text +
"\", is invalid. Please enter a number between 1 and 100";
JOptionPane.showMessageDialog(confirmBtn,
warning,
"Invalid Input", JOptionPane.ERROR_MESSAGE);
textfield.setText("");
textfield.requestFocusInWindow();
}
}
}
// true if data is a number between 1 and 100
public boolean isTextValid(String text) {
try {
int number = Integer.parseInt(text);
if (number > 0 && number <= 100) {
return true;
}
} catch (NumberFormatException e) {
// one of the few times it's OK to ignore an exception
}
return false;
}
}
Why don't you check if your jDialog is visible?
yourJD.setVisible(true);
while(yourJD.isVisible())try{Thread.sleep(50);}catch(InterruptedException e){}
this works, also.
import javax.swing.JOptionPane;
or if you're already swinging
import javax.swing.*;
will have you covered.
After conditional trigger JOptionPane to send your warning or whatever modal message:
JOptionPane.showMessageDialog(
null,
"Your warning String: I can't do that John",
"Window Title",
JOptionPane.ERROR_MESSAGE);
check your options for JOptionPane.* to determine message type.