Develop Reference

Why can't I add an attribute to my constructor?

public class Ouvrier extends javax.swing.JFrame {
private final int numOuvrier;
public Ouvrier(int numOuvrier) {
initComponents();
this.numOuvrier=numOuvrier;
}
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new Ouvrier().setVisible(true);
}
});
}
I have added an attribute to a constructor and an error appears in the main frame - why is that?

new Ouvrier(0).setVisible(true);
I dont know what numOuvrier means, but you need pass it.

How to create JFrame from another main class as separate thread

I want to create one Jframe from another class (main class) and then I want to display Jframe only if no error in main method. Otherwise I want to create & display dialog by passing that same jframe.
I forgot thread concept anywhere give me the solution, I tried below code, that prints "abcde" but not display the frame program complete.
Note : there is no main method in JFrame od ErrorDialog. They are just custom container.
public class Start{
public static Main mf=null;
public static void main(String args[]){
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
mf = new Main();
}
});
try {
// Some extra code
System.out.println("abcde"); // this is print and then program complete
mf.setVisible(true); // this line will not run
} catch (Exception e) {
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new ErrorDialog(mf, true).setVisible(true);;
}
});
}
}
}

Try my suggestion its working..
Just use invokeAndWait() method insted of using invokeLater() method.
Because invokeLater() method create NullpointerException.
But invokeAndWait() must be inside try-catch block.
try {
java.awt.EventQueue.invokeAndWait(new Runnable() {
public void run() {
mf = new Main();
}
});
} catch (Exception e) {
System.out.println(e);
}

Controller to initialize Instances of JFrame

I've got several unrelated swing classes that are instances of JFrame. The issue is, I'd like to be able to create a controller class with a static method to load the appropriate frames as needed. I'm experiencing difficulty with the following code as many of components are failing to load. I suspect that the issue is with the event dispatch thread. Below is the code that doesn't work:
import javax.swing.JFrame;
import javax.swing.SwingUtilities;
public class Controller {
private Controller() {
}
public static void initialize(final JFrame frame) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
JFrame selectionFrame = frame;
}
});
}
public static void main(String[] args) {
Controller.initialize(new SampleFrame());
}
}
The program loads the frame and toolbar components but other components fail to load. NOTE: The program runs just fine if I refactor the Controller like so :
public class Controller {
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
new SampleFrame();
}
});
}
}

How to access my JFrame on EDT

I have a class on which it hold a JFrame, and on my JFrame, it contains some methods that i would want to call. The problem is that my class is in the main thread and mFrame is now delegated to the EDT thread, so how do i sent instructions to EDT to run those methods?
Update:
This is my FrameRadar that extends JFrame, as you see i have a update method, basically there is also a update on mDisplay and mRadar, those are jpanel.
FrameRadar Class ...(
public class FrameRadar{
...
public void update() {
mAccessor.getmDisplay().update();
mAccessor.getmRadar().update();
}
This is my MainRadar class, it contains a FrameRadar on which i also have a update method. That update method will call jframe's update.
class MainRadar(
....
private FrameRadar mFrame;
....
public StateMainGame() {
init();
}
public void init() {
....
java.awt.EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
mFrame = new FrameRadar();
mFrame.setVisible(true);
}
});
}
....
public void update() {
mFrame.update();
}
So as you see, MainRadar.Update-> FrameRadar->Update-> Jpanels->Update. The problem is that i cannot use
mFrame.update();

Java Event Queue : how to update component in JFrame

I have read about that when programming Java Swing, we should put these components into Java Event Queue, because Java Swing thread is not-thread safe.
But, when I use Event Queue, I don't know how to update component properties (for example : set text for label or change something..). Here is my code :
public class SwingExample {
private JLabel lblLabel;
SwingExample(){
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
lblLabel = new JLabel("Hello, world!", JLabel.CENTER);
frame.getContentPane().add(lblLabel); // adds to CENTER
frame.setSize(200, 150);
frame.setVisible(true);
}
public void setLabel(){
lblLabel.setText("Bye Bye !!!");
}
public static void main(String[] args) throws Exception
{
SwingExample example = null;
EventQueue.invokeLater(new Runnable()
{
public void run()
{
example = new SwingExample(); // ERROR : Cannot refer to non-final variable inside an inner class defined in different method
}
});
// sometime in the futures, i want to update label, so i will call this method...
example.setLabel();
}
}
I know, if I write SwingExample example = new SwingExample(); the error won't appear again, but if i use that, I cannot process example.setLabel later.
Please tell me about this error and how to fix this.
Thanks :)

By having your SwingExample instance as a field, you can reference it inside the inner classes without it being final.
public class SwingExample {
private JLabel lblLabel;
private static SwingExample instance;
SwingExample() {
// code omitted
}
public void setLabel() {
lblLabel.setText("Bye Bye !!!");
}
public static void main(String[] args) throws Exception {
EventQueue.invokeLater(new Runnable() {
public void run() {
instance = new SwingExample();
}
});
// ...
EventQueue.invokeLater(new Runnable() {
public void run() {
instance.setLabel();
}
});
}
}