Member Avatar for rogue005

I am doing a project using Java swing in Netbeans and I am using their in-built GUI generator thing. I have created a socket in one frame and i need to use the same object in another frame. these frames are present in the same package but are different classes.

Please tell me how to use that object in another frame!

  • 5 Contributors
  • 5 Replies
  • 3K Views
  • 3 Months Discussion Span
  • Latest Post Latest Post by Ezzaral

Dani AI

Generated

Passing the same socket (or any shared resource) between windows is a dependency-management problem, not a Swing quirk. Keep one owner for the socket, then pass a reference to anything that needs it. is spot on about constructor injection. To reduce coupling and make testing easier, let a small controller/service own the socket and hand it to your UI classes. Also, never do blocking I/O on the Swing event dispatch thread; run it on a background worker so the UI stays responsive.

Here is a simple pattern that scales beyond two windows:

final class ConnectionManager {
  private final Socket socket;
  ConnectionManager(Socket socket) { this.socket = socket; }
  public Socket getSocket() { return socket; }
}

final class AppController {
  private final ConnectionManager cm;
  AppController(ConnectionManager cm) { this.cm = cm; }

  void start() {
    EventQueue.invokeLater(() -> new LoginWindow(cm).setVisible(true));
  }

  void openChat() {
    EventQueue.invokeLater(() -> new ChatWindow(cm).setVisible(true));
  }
}

For ’s follow-up: NetBeans forms often generate a no-arg constructor and a default launcher that calls new SomeWindow().setVisible(true). If you change your window to require a dependency, you must also change the creation site to pass it. Alternatively, keep the no-arg constructor and inject via a setter before showing the window:

ConnectionManager cm = new ConnectionManager(new Socket(host, port));
SomeWindow w = new SomeWindow();   // no-arg constructor kept for GUI builder
w.setConnectionManager(cm);        // your setter
w.setVisible(true);

Practical tips: prefer one JFrame and swap JPanels instead of multiple frames, close the socket on application shutdown (e.g., add a WindowListener), and route long-running reads/writes through a SwingWorker or executor to avoid freezing the UI.

Recommended Answers

All 5 Replies

Member Avatar for phoenix911

first of all, never use the automatic GUI generator... as it is very hard to read/re-use/edit...

always create your GUIs yourself... it may take a lil longer but is much more worth the trouble at the end.

note:sorry for the hate and off topic, just it'll help alot later on

Edited by phoenix911 because: n/a
Member Avatar for javaAddict

In the same way you do it in any other class with any other object.
In one class make that object as a global attribute and either set it to be public or use get/set methods.

public class OneFrame {
  public SomeObject so = null;
  // create it in this class and do things with it

  public OneFrame() {
    so = new SomeObject();
  }
}

Since you didn't explain your problem very well, I am going to assume that when you click a button in this frame another opens and you want that object to be passed to the other frame?
Then at the second frame have the constructor take as parameter that object and pass the one you have at first frame as parameter.

public class OneFrame {
  public SomeObject so = null;
  // create it in this class and do things with it

  public OneFrame() {
    so = new SomeObject();
  }

  private void openNewFrame() {
    NewFrame nf = new NewFrame(so);
  }
}
public class NewFrame{
  public SomeObject so = null;

  public NewFrame(SomeObject so) {
    this.so = so;
  }
}
Member Avatar for rogue005

Thanks javaAddict!
That really solved my problem! Thanks!!!

Member Avatar for crowgol

Can I ask a follow up question? In the definition of the new frame:

public class NewFrame{
  public SomeObject so = null;

  public NewFrame(SomeObject so) {
    this.so = so;
  }
}

You have passed the SomeObject but in the 

 public static void main(String args[]) {
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new NewFrame().setVisible(true);
            }
        });
    }

I can't add the SomeObject to new NewFrame().... (I get an error)

Edited by Nick Evan because: Fixed formatting
Member Avatar for Ezzaral

The original question was how to pass an object to a subsequent frame. That presupposes that NewFrame is dependent upon the object, which has already been created. In your example, that does not apply. If you don't have SomeObject you need to pass along, then there is no point in even creating the NewFrame constructor that accepts SomeObject - just use the plain empty constructor.

Be a part of the DaniWeb community

We're a friendly, industry-focused community of developers, IT pros, digital marketers, and technology enthusiasts meeting, networking, learning, and sharing knowledge.