I am working on a JAVA desktop application that has two frames, users clicks a button on frame 1, response based on the selected option would be updated to the database. While the response is being updated, frame 2 should be displayed.
If I set the frame 2 to visible before the database update, frame 2 is displayed but with empty content i.e panels of frame 2 are not displayed. But once the database update is completed, the contents of the frame are shown.
button1.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
frame1.setVisible(false);
frame2.setVisible(true);
Utilities.updateToDB("clicked button1");
}
});
Content of Frame 2 should be shown while the database update is taking place or before it.
For this particular case I suggest you to use:
A Swing Worker as shown in this example and the tutorial
Something along the lines:
protected String doInBackground() throws Exception {
try {
Thread.sleep(5000); //Simulates long running task (your database update)
} catch (InterruptedException e) {
e.printStackTrace();
}
return "Updated"; //Returns the text to be set on your status JLabel once the update is done
}
#Override
protected void done() {
super.done();
try {
// Here update your GUI or do whatever you want to do when the update is done.
textfield.setText(get()); //Set to the textField the text given from the long running task
} catch (InterruptedException | ExecutionException e) {
e.printStackTrace();
}
}
And on your ActionListener something like:
private ActionListener listener = (e -> {
frame2.setVisible(true); //suggested use of cardlayout and display nextCard here.
worker.execute(); //Initializes long running task
});
However I suggest you not to use multiple JFrames: The Use of Multiple JFrames: Good or Bad Practice? and use a CardLayout instead, for example
Related
I'm trying to display the text of Successful Login before a system sleep for 3,000 miliseconds. Its not working when I place it right after the set text. How do I get it to display then pause so there is a bit of delay so the user knows that they loging in?
After the user correctly logs-in it will continue to a different class where the JFrame will close
l_Message.setForeground(Color.green);
l_Message.setText("Succesful Login");
try{
Thread.sleep(3000);
} catch(InterruptedException ex) {
Thread.currentThread().interrupt();
}
PLOGIN post_login = new PLOGIN();
post_login.postlogin_UI(login_JFrame);
See Concurrency in Swing for the reason why you're having problems
See How to use Swing Timers for a possible solution
import javax.swing.Timer
//...
l_Message.setForeground(Color.green);
l_Message.setText("Succesful Login");
Timer timer = new Timer(3000, new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
PLOGIN post_login = new PLOGIN();
post_login.postlogin_UI(login_JFrame);
}
});
timer.start();
Assuming that you are calling this from outside of the GUI thread(which I believe that you should be), you could try the following:
EventQueue.invokeLater(() -> {
l_Message.setForeground(Color.green);
l_Message.setText("Succesful Login");
});
try{
Thread.sleep(3000);
} catch(InterruptedException ex) {
Thread.currentThread().interrupt();
}
PLOGIN post_login = new PLOGIN();
post_login.postlogin_UI(login_JFrame);
i.e. schedule GUI operations to the GUI thread
I have a jList called todoList
When the user click on an item in the list, it stays selected. But I would like the currently selected item in the list to deselect "by itself" after 400 milliseconds when the mouse exits the jList.
This must only run if there is something already selected in the list.
I am using Netbeans IDE and this is what is have tried so far:
private void todoListMouseExited(java.awt.event.MouseEvent evt) {
if (!todoList.isSelectionEmpty()) {
Thread thread = new Thread();
try {
thread.wait(400L);
todoList.clearSelection();
} catch (InterruptedException ex) {
System.out.println(ex);
}
}
}
and
private void todoListMouseExited(java.awt.event.MouseEvent evt) {
if (!todoList.isSelectionEmpty()) {
Thread thread= Thread.currentThread();
try {
thread.wait(400L);
todoList.clearSelection();
} catch (InterruptedException ex) {
System.out.println(ex);
}
}
}
These both just make everything stop working.
My though process was that i need to create a new Thread that will wait for 400 milliseconds and then run the clearSelection() method of the jList. This would happen every time the mouse exits the list and run only if there is something in the list that is already selected.
I hope I am explaining my problem thoroughly enough.
The problem is that you are blocking the AWT-Event-Thread.
The solution is to use a swing timer:
private void todoListMouseExited(java.awt.event.MouseEvent evt)
{
if (!todoList.isSelectionEmpty()) {
new Timer(400, new ActionListener() {
public void actionPerformed(ActionEvent evt) {
todoList.clearSelection();
}
}).start();
}
}
The problem is that Object#wait is waiting(rather than sleeping) to be notified but this is not happening. Instead the timeout causing an InterruptedException bypassing the call to clearSelection.
Don't use raw Threads in Swing applications. Instead use a Swing Timer which was designed to interact with Swing components.
if (!todoList.isSelectionEmpty()) {
Timer timer = new Timer(400, new ActionListener() {
public void actionPerformed(ActionEvent evt) {
todoList.clearSelection();
}
});
timer.setRepeats(false);
timer.start();
}
How can I smoothly move the JButton if action performed (eg the button is pushed). Here's my example but it doesnt work propely:
public void actionPerformed(ActionEvent event) {
for(int i = 0; i<50; i++){
ww.button.setLocation(ww.button.getLocation().x+1, ww.button.getLocation().y);//ww is a JFrame child
try {
Thread.sleep(20);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
After action performed I get a delay in 20*50 ms and button location set in previous loc + 50px, without intermediate locations.
Always try to avoid Thread while working with Swing. In your code it will make main EDT thread to sleep and that's why you are not able to view intermediate locations. Try this with using Swing Timer and you will get it working as intended. Take a look here: How to Use Swing Timers and also try using Swing workers.
I have a save button in a JFrame ;on clicking save the 'save' text sets to 'saving....'; I need to set that text as 'saved' after a delay of 10 seconds.How is it possible in java?
Please help...
try {
Thread.sleep(4000);
} catch (InterruptedException e) {
e.printStackTrace();
}
This is what i did...but this wont shows as 'saving' during that delayed time.
If you want to provide the user with visual feedback that something is going on (and maybe give some hint about the progress) then go for JProgressBar and SwingWorker (more details).
If on the other hand you want to have a situation, when user clicks the button and the task is supposed to run in the background (while the user does other things), then I would use the following approach:
button.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
button.setEnabled(false); // change text if you want
new SwingWorker<Void, Void>() {
#Override
protected Void doInBackground() throws Exception {
// Do the calculations
// Wait if you want
Thread.sleep(1000);
// Dont touch the UI
return null;
}
#Override
protected void done() {
try {
get();
} catch (Exception ignore) {
} finally {
button.setEnabled(true); // restore the text if needed
}
}
}.execute();
}
});
Finally, the initial solution that was using the Swing specific timer:
final JButton button = new JButton("Save");
button.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
// Take somehow care of multiple clicks
button.setText("Saving...");
final Timer t = new Timer(10000, new ActionListener() {
#Override
public void actionPerformed(ActionEvent evt) {
button.setText("Saved");
}
});
t.setRepeats(false);
t.start();
}
});
This question & first 3 answers are heading down the wrong track.
Use a JProgressBar to show something is happening. Set it to indeterminate if the length of the task is not known, but presumably you know how much needs to be saved and how much is currently saved.
Don't block the EDT (Event Dispatch Thread) - the GUI will 'freeze' when that happens. Use a SwingWorker for long running tasks. See Concurrency in Swing for more details.
The best is to use a timer and its method execute with a delay : http://developer.apple.com/library/mac/documentation/java/reference/javase6_api/api/java/util/Timer.html#schedule(java.util.TimerTask, long). Use a timertask to wrap your runnable and that's it.
Is there a way to close a JDialog through code such that the Window event listeners will still be notified? I've tried just setting visible to false and disposing, but neither seem to do it.
Closing a window (with dispose()) and hiding it (with setVisible(false)) are different operations, and produce different events -- and closing it from the operating system is yet another different operation that produces yet a different event.
All three will produce windowDeactivated to tell you the window's lost focus, but dispose() will then produce windowClosed, while closing from the OS will first produce windowClosing. If you want to handle both of these the same way, you can set the window to be disposed when closed:
window.setDefaultCloseOperation(WindowConstants.DISPOSE_ON_CLOSE);
In general, setVisible(false) implies that you might want to use the window again, so it doesn't post any window events (apart from windowDeactivated). If you want to detect the hiding of a window, you need to use a ComponentListener;
window.addComponentListener(new ComponentAdapter() {
#Override
public void componentHidden(ComponentEvent e) {
System.out.println("componentHidden()");
}
})
Note though that this will pretty much only work for explicit setVisible() calls. If you need to detect hiding more generally, you can use a HierarchyListener, but it's probably more trouble than it's worth.
window.addHierarchyListener(new HierarchyListener() {
#Override
public void hierarchyChanged(HierarchyEvent e) {
System.out.println("valid: " + window.isValid());
System.out.println("showing: " + window.isShowing());
}
});
Note that when you dispose a window you'll get a couple of HierarchyEvents, first for hiding and then for invalidation, but when you hide it with setVisible() it's still valid, so you won't get the invalidation.
I don't seem to have your problem. When I use the code below windowDeactivated() is called for either setVisible( false ) or dispose() and windowClosed() is also called for dispose().
ClosingDialog.java:
public class ClosingDialog extends JDialog {
public ClosingDialog(Frame owner, String title, boolean modal) {
super(owner, title, modal);
JPanel contentPanel = (JPanel) this.getContentPane();
JButton setVisButton = new JButton("setVisible( false )");
setVisButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
ClosingDialog.this.setVisible(false);
}
});
JButton disposeButton = new JButton("dispose()");
disposeButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
ClosingDialog.this.dispose();
}
});
contentPanel.setLayout(new FlowLayout());
contentPanel.add(setVisButton);
contentPanel.add(disposeButton);
this.addWindowListener(new WindowListener() {
public void windowActivated(WindowEvent e) {
System.out.println("windowActivated");
}
public void windowClosed(WindowEvent e) {
System.out.println("windowClosed");
}
public void windowClosing(WindowEvent e) {
System.out.println("windowClosing");
}
public void windowDeactivated(WindowEvent e) {
System.out.println("windowDeactivated");
}
public void windowDeiconified(WindowEvent e) {
System.out.println("windowDeiconified");
}
public void windowIconified(WindowEvent e) {
System.out.println("windowIconified");
}
public void windowOpened(WindowEvent e) {
System.out.println("windowOpened");
}
});
this.setSize(300, 300);
}
}
Dispatch a windowClosing event to the Window. Check out the ExitAction example from the Closing an Application entry.
Untested suggestion:
Have you tried getWindowListeners() and then iterating around to fire windowClosed() to each of the WindowListeners?
EDIT: the above suggestion is wrong. Keeping it for posterity.
I'm afraid calling dialog.dispose() works fine for me in my simple example.
I wanted to fire a windowClosing event from the code (just as if the user clicked the X), because I have an extra close button in the JDialog and want the same WindowListener (that I implemented using a WindowAdapter) to be run when the X is clicked and when the button is clicked. Running dispose() only fires windowClosed, not windowClosing, and I want a message to appear before the window is closed, for confirmation. I also didn't manage to fire windowClosing via JDialog's method processWindowEvent since it is protected.
Here is how I got it working though:
WindowAdapter adapter = (WindowAdapter)jdialog.getWindowListeners()[0];
adapter.windowClosing(new WindowEvent((Window)jdialog, WindowEvent.WINDOW_CLOSING));
Hope that helps someone.