Question

I am trying to program a java application that consists of several windows using JFrame.

Each JFrame contains a JTextField and buton to go to the next JFrame.

I need to retrieve all the information entered by the user at the end.

I created an event click on the buton to save to a public class all the data that the user introduce in the JTextField. I named that public class myData, which has a static attributes.

The problem is that I can not access this class from the button listener function.

I get an error: cannot refer to an non final variable inside an inner class defined in a different method.

My goal is to be able to share the class myData between different methods of a different class.

E.g. I have a class named myClass1 and myClass2, so I want to share the myData attribute between myClass1 methods and myClass2 methods.

Please anyone can someone help me? or propose another way to do this!

Thanks in advance !

Answer 1

All of the calls about MVC etc. are valid, but this isn’t that hard.

What you want to do is in your Main, you can create your Data (Model) class, the class that holds all of your information.

So, you can do something like this:

public class F1 ... {
    private final Data myData;

    public F1(Data theData) {
        myData = theData;
    }

    ....
}

public class Main {
    Data myData;

    public static void main(String args[]) {
        Main m = new Main();
        m.setMyData(new Data());

        F1 f = new F1(m.getMyData());
        ...
     }
}

Then, later, when F1 calls F2, simply do the same thing — create F2 with the Data passed in earlier by the constructor. That way, as each Frame runs its course, they’re all working on the same instance of Data. When all is done, the single instance of Data is left within the Main class for you to do with what you will.

There are better ways to reorganize your entire program, but this should give you ideas on how to get over the hump you’re having right now.

Addenda:

There are several things you can do.

When your get the ActionEvent, it contains a source. That source is the component that generated the event (most likely a Button in this case). If you know where the button is located in the hierarchy of things, you get to your Frame directly. In the pastebin example, you have Frame -> Panel -> Button. So, if you have the Button, you cat get to the Frame.

public void actionPerformed(ActionEvent e) {
    JButton sourceButton = (JButton)e.getSource();
    F1 f1 = (F1)sourceButton.getParent().getParent();
    Data myData = f1.getMyData();
    data.setField(...);
}

Again, this is not the recommended ways of doing things. The tutorials have decent examples of using MVC and property change listeners and the whole kit. But this should get you to where you want to go.