Question

Not sure if this has been asked before, it’s a bit difficult to explain.

I have 2 classes, Class A and Class B

Class A creates an instance of Class B (which is a dialog box using JDialog).
The user is then asked for text input (stored in a String variable).

How do I tell Class A that the user has now updated the variable and get a copy of it?

Using Java Swing btw,

Thanks

T

Answer 1

If the dialog is modal, then the code is blocked until the dialog is closed:

dialog.setVisible(true);
// blocked here until the dialog is closed. The dialog stores the input in a
// field when OK is clicked in the dialog
if (dialog.getTextInputtedByTheUser() != null) {
    ...

If the dialog is not modal, then you need to make it call a callback method when the validation happens. This is what MyFrame would contain

private void showDialog(
    MyDialog dialog = new MyDialog(this);
    dialog.setVisible(true);
}

public void userHasInputSomeText(String text) {
    // do whatever you want with the text
    System.out.println("User has entered this text in the dialog: " + text);
}

and in MyDialog:

private MyFrame frame;
public MyDialog(MyFrame frame) {
    super(frame);
    this.frame = frame;
}
...
private void okButtonClicked() {
    String text = textField.getText();
    frame.userHasInputSomeText(text);
}