I am a beginner in GUI programming and I am working on a project with a different kind of button.
For one of my Jbutton, when pressed it calls another frame that performs a task.
However, that frame goes on the background when I am working on the main frame.
When you press again the button for the second time a null pointer error is generated.
I want to be able to just bring back the frame that is in the background when the button is pressed for the second time.
changecontrastB.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
// calls the contrast adjuster function
ContrastAdjuster mycontrast= new ContrastAdjuster();
// running that function which brings that frame forward
mycontrast.run("Brightness/Contrast...");
mycontrast.setVisible(true);
if (changecontrastB.isSelected() && mycontrast.isVisible()==false )
{
changecontrastB.setEnabled(false);
mycontrast.setVisible(true);
}
}
});
changecontrastB is my actual Jbuton.
Do the following:
In the class with the button, create a member variable of type JFrame:
JFrame frame = null;
In the action listener called from the button, include an if like this (you need to adapt it to your class names):
if (frame = null)
frame = new MyFrame(); //Other initializations might be needed too.
else
frame.toFront();
Related
I am building an application which I need to open a JFrame in another JFrame while the first JFrame is disabled.
The problem is when I want to close the second JFrame I need to enable the first JFrame.
I have tried in several ways, but it is not working properly and I was not able to reach one goal in each of them. I need to reach both goals:
Disabling the first Frame when the second Frame is opened
Enabling it when the second Frame is closed.
Here is part of my code:
private void jButton10ActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
PaymentJFrame pjf = new PaymentJFrame();
//setEnableValue(false);
//enableFrame();
this.setEnabled(false);
pjf.setVisible(true);
if (!pjf.isActive()){
this.setEnabled(true);
}
}
This code dose not enable the First Frame at all.
I have tried to use it in another way by adding an enable when the second Frame is closed but it is not working:
//Class in first Frame
private void jButton10ActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
PaymentJFrame pjf = new PaymentJFrame();
//setEnableValue(false);
//enableFrame();
this.setEnabled(false);
pjf.setVisible(true);
}
//Class in second Frame
private void formWindowClosed(java.awt.event.WindowEvent evt) {
// TODO add your handling code here:
FinancialDocumentsJFrame.setEnableValue(true);
}
Dose any one know how can I reach these goals?
The first Frame is the main frame and the second frame is a class that I make the frame object from it in order to show and get more information from users.
I ma using netBeans IDE designer.
First of all, a Swing application should only have one JFrame, other windows can be JDialog or somethign else. As for your question, use this code as an example. It uses a listener to detect the closing event of the second window. The following code should be in the (first) JFrame (it looks like you have a button there)
private void jButton10ActionPerformed(java.awt.event.ActionEvent evt) {
JDialog paymentDialog = new JDialog();
MyFirstFrame.this.setEnabled(false);
paymentDialog.setVisible(true);
paymentDialog.addWindowListener(new WindowAdapter() {
#Override
public void windowClosed(WindowEvent e) {
MyFirstFrame.this.setEnabled(true);
}
});
}
You can create your own dialog by extending JDialog as you did with the frames, and use the custom dialog in this code. Also instead of setting the JFrame enabled or disabled, you could consider using a modal JDialog that blocks actions to the JFrame while the dialog is active.
And further still, there is the setAlwaysOnTop(boolean) for Swing windows.
use this.dispose()method JFrame has dispose() method for JFrame Close
I decided to use jDialog as it was recommended by many people on the net.
I used a jDialog and copied all the objects I had used in the second jFrame.
It worked the way I wanted it to do.
My only problem is that why java hasn't prepared a different way to answer this need.
I'm using an action listener in the first jFrame to open the second Frame which I have used jDialog for it.
private void jButton3ActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
ActivityJDialog ajdf = new ActivityJDialog(this,true);
ajdf.setVisible(true);
}
And I have copied everything I wanted to have into this jDialog.
public class ActivityJDialog extends java.awt.Dialog {
//Document Attributes
int documentStatus = -1;
int documentType = -1;
/**
* Creates new form AcrivityJDialog
* #param parent
* #param modal
*/
public ActivityJDialog(java.awt.Frame parent, boolean modal) {
super(parent, modal);
initComponents();
/*if(false) // Full screen mode
{
// Disables decorations for this frame.
//this.setUndecorated(true);
// Puts the frame to full screen.
this.setExtendedState(this.MAXIMIZED_BOTH);
}
else // Window mode
{*/
// Size of the frame.
this.setSize(1000, 700);
// Puts frame to center of the screen.
this.setLocationRelativeTo(null);
// So that frame cannot be resizable by the user.
this.setResizable(false);
//}
}
Thank you all for helping.
The code snippet below sets text in a JLabel, which is added to a JPanel, which is attached to a JFrame. No matter what I do though (such as repaint(), revalidate(), etc) I cannot get the UI to update the text until the Action Listener is done.
I have never had this problem before, possible because I have never had to have several things happen in a single firing of Action Listener. What am I missing?
TL;DR Why does the following not update the text on the screen until it has finished firing the Action Listener, even if I put in repaint() after each listPanel.add()?
final JFrame guiFrame = new JFrame();
final JPanel listPanel = new JPanel();
listPanel.setVisible(true);
final JLabel listLbl = new JLabel("Welcome");
listPanel.add(listLbl);
startStopButton.addActionListener(new ActionListener(){#Override public void actionPerformed(ActionEvent event){
if(startStopButton.getText()=="Start"){
startStopButton.setVisible(false);
listPanel.remove(0);
JLabel listLbl2 = new JLabel("Could not contact”);
listPanel.add(listLbl2);
JLabel listLbl2 = new JLabel("Success”);
listPanel.add(listLbl2);
}
}
guiFrame.setResizable(false);
guiFrame.add(listPanel, BorderLayout.LINE_START);
guiFrame.add(startStopButton, BorderLayout.PAGE_END);
//make sure the JFrame is visible
guiFrame.setVisible(true);
EDIT:
I attempted to implement SwingWorker, but still the interface is not updating until the action interface finishes firing. Here is my SwingWorker code:
#Override
protected Integer doInBackground() throws Exception{
//Downloads and unzips the first video.
if(cameraBoolean==true)
panel.add(this.downloadRecording(camera, recording));
else
panel.add(new JLabel("Could not contact camera "+camera.getName()));
panel.repaint();
jframe.repaint();
return 1;
}
private JLabel downloadRecording(Camera camera, Recording recording){
//does a bunch of calculations and returns a jLabel, and works correctly
}
protected void done(){
try{
Date currentTime = new Timestamp(Calendar.getInstance().getTime().getTime());
JOptionPane.showMessageDialog(jframe, "Camera "+camera.getName()+" finished downloading at "+currentTime.getTime());
}catch (Exception e){
e.printStackTrace();
}
}
Basically, SwingWorker (as I implemented it) is not properly updating the JPanel and JFrame. If I try to do the repaint in the "done()", they are not updated either. What am I missing?
Additionally, as soon as the JOptionPane displays itself, no more panels can be added to my jframe. I am unsure what is causing that either.
The action listener is being executed on the Event Dispatch Thread. For tasks like that, consider using a SwingWorker.
This would allow you to process your logic without blocking the updates (and thus the repaints) of the JFrame.
At a high level, this is what I mean:
startStopButton.addActionListener(new ActionListener(){#Override public void actionPerformed(ActionEvent event){
if(startStopButton.getText()=="Start"){
// Start SwingWorker to perform whatever is supposed to happen here.
}
You can find some information on how to use SwingWorker here, should you need it.
I have this program with different screens (represented by JPanels). Every time a screen opens I rebuild that panel, and place it on the JFrame.
Now, when I build the panel for the first time (always the same function) and press a button, the code attached to it will run. When I rebuild the screen the eventSource will never be equal to the actual eventSource.
See code:
public class NewUserScreen extends JPanel implements MouseListener{
//SButton inherits from Component
SButton sb;
...
public void SetFields(){
removeAll();
revalidate();
repaint();
...
sb = new SButton(new Point(282, 295), "Save");
sb.addMouseListener(this);
add(sb);
...
}
...
#Override
public void mouseReleased(MouseEvent arg0) {
if(arg0.getSource().equals(sb)){
DBManager.addUser(...);
}else{
//So after the 2nd build, it will always run this code :(
ScreenManager.OpenAdminS();
}
}
}
have this program with different screens (represented by JPanels).
Every time a screen opens I rebuild that panel, and place it on the
JFrame.
use CardLayout instead of remove and add a new view to JFrame
Now, when I build the panel for the first time (always the same
function) and press a button, the code attached to it will run. When I
rebuild the screen the eventSource will never be equal to the actual
eventSource.
have to call (re)validate() and repaint() for parent (JFrame in your case), one time, as last code lines (after all changes to container are done)
I am busy doing a school project and hoped some awesome people out there could help me.
I currently have a Main, a Log in GUI and a Search frame (designed with Netbeans Gui dev).
I have an actionPerformed(ActionEvent e) method, where I am struggling is to access the Log in button that is on my Log in GUI. Currently I am doing this.
In my constructor: Declare the Frame. LogInFrame x = new LogInFrame();
In
public actionPerformed(ActionEvent eve)
{
if(eve.getSource()==x.LogInBtn())
{
x.setVisible(false);
}
}
At the moment the button isn't responding, so I was wondering if I was doing anything wrong.
The current Frame is just a standard frame. Really simple
public static void main (String[] args)
{
JFrame LogInFrame = new JFrame ("Log in");
LogInFrame.setSize (300, 300);
JButton close = new JButton ("Hid frame");
LogInFrame.getContentPane ().add (close);
}
}
Thats about everything that is needed. The problem does not lie with the GUI itself as I can run the GUI in netbeans fine. I can use the auto generated actionPerformed method of the button by double clicking on it. But i want to be able to access my GUI's compenents in my main.(tell the button what to do from my main). I have made sure that the button is public and can be accessed. I dont get any physical "coding" errors, the code just doesnt seem to be working (the button isnt responding if I add events from my main)
I have a problem with my application where the user will open more than one window at a time. And i have added dispose() method to call on closing the window. Now i should keep at-least one window open all the time so that the application does not hides without closed fully. If you don't understand read the following scenario:
I have window A and window B opened at the same time. Now i can close either window A or Window B but not both. In other words window B should be allowed to close only if window A is opened and vice versa. How do i do this in swing ??
A simple kind-of windowManger is not really tricky, all you need is
WindowListener which keeps tracks of the Windows it's listening to
a defined place to create the windows and register the the listener
make the windows do-nothing-on-close and make the listener responsible for the decision of whether to close or not (will do so for all except the last)
Some snippet:
// the listener (aka: WindowManager)
WindowListener l = new WindowAdapter() {
List<Window> windows = new ArrayList<Window>();
#Override
public void windowOpened(WindowEvent e) {
windows.add(e.getWindow());
}
#Override
public void windowClosing(WindowEvent e) {
if (windows.size() > 1) {
windows.remove(e.getWindow());
e.getWindow().dispose();
}
}
};
// create the first frame
JFrame frame = createFrame(l);
frame.setVisible(true);
// a method to create a new window, config and add the listener
int counter = 0;
private JFrame createFrame(final WindowListener l) {
Action action = new AbstractAction("open new frame: " + counter) {
#Override
public void actionPerformed(ActionEvent e) {
JFrame frame = createFrame(l);
frame.setVisible(true);
}
};
JFrame frame = new JFrame("someFrame " + counter++);
frame.setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);
frame.add(new JButton(action));
frame.addWindowListener(l);
frame.pack();
frame.setLocation(counter * 20, counter * 10);
return frame;
}
Just a possible approach...
Create a class, call it WindowManager, that manages creation and disposal of windows.
It could for example retain the count of the windows currently open, and allow a dispose operation only if there are more than one windows "alive", otherwise show a confirm message with JOptionPane telling the user "Really close? That would terminate the application." or something like that.
The "tricky" part is that you have to do this kind of window-related operations throughout the WindowManager, otherwise everything would screw up.
Dunno if Swing has something like this built-in, I've never seen such a scenario.
simply check if the other window is open before closing with window.isVisible();