实现jframe类的接口

Question

Been creating a bunch of JFrame classes using the appropriate wizard.

Created an interface and decided to make the JFrame classes implement this interface. Usually, when adding an implements CaptureObserver statement to a class, the class declaration is underlined in red, the error is saying

System.Bill.Operation.BillForm is not abstract and does not override abstract method onError(com.lti.civil.CaptureStream,com.lti.civil.CaptureException) in com.lti.civil.CaptureObserver

How can I resolve this?

Answer 1

What that error means is that your class implements the interface but it does not contain all of the methods defined by that interface. Solution: give the class the missing methods. In your case, the error is telling you exactly what method of CaptureObserver that you're missing, onError(com.lti.civil.CaptureStream,com.lti.civil.CaptureException) .

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A few unrelated issues and suggestions:

been creating a bunch of JFrame classes using the appropriate wizard.

If you're new to Swing, avoid using "wizards" to create your GUI's, but instead try making them from hand. It will give you a much better insight into using the library. Also, strive to create JPanels rather than JFrames as this will give your GUI classes much greater flexibility. With a JPanel, you can put it into a JFrame, or if desired, a JDialog, a JOptionPane, a JApplet, another JPanel, a "view" of a CardLayout, etc...

Created an interface and decided to make the JFrame classes implement this interface.

It's usually best to avoid having your GUI/view classes implementing listener interfaces as this gives one class too much disparate responsibility. Perhaps this should be an anonymous inner class or part of a separate conctrol class.

Usually, when adding an "implements CaptureObserver" statement to a class, the class declaration is underlined in red, the error is saying "System.Bill.Operation.BillForm is not abstract and does not override abstract method onError(com.lti.civil.CaptureStream,com.lti.civil.CaptureException) in com.lti.civil.CaptureObserver" how can i resolve it. pls help...

This we've discussed above.

Answer 2

You need to implement the methods defined in your interface.

If you have this:

public interface CaptureObserver {
    public void onError(CaptureStream stream, CaptureException exc);
}

Then you need this:

public class BillForm extends JFrame implements CaptureObserver {
    // Don't forget your constructor
    public BillForm() {
        super();
    }

    @Override
    public void onError(CaptureStream stream, CaptureException exc) {
         // Code
    }
}