如何在内存中设置ActionListener？

Question

I have Submit JButton which has two ActionListeners

Category cat = new Category();

//this is launched second
submit.addActionListener(new ConfirmListener(new CategoryService(), cat));

//this is launched first. Set values
submit.addActionListener(new ActionListener() {

    public void actionPerformed(ActionEvent e) {
        String title = field.getText();
        cat.setTitle(title);
    }

});

Are they put on stack and they are launched as they pop? The second listener sets object's values and the first one is using the object.

Answer 1

The 'ActionListener's are stored in a list data structure which is a member of the component. They are usually called in the order in which they are added, but this is not guaranteed and can be handled differently by, for example, subclasses.

Therefore, it is considered bad practice to rely on a specific invocation order of listeners. If an order is needed, create a composite listener which in turn calls your actual listener methods in the order in which you need them.

Answer 2

ActionListener位于存储在EventListenerList中的幕后，因此将按照添加顺序执行它们。