Question

comboBox.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent event) {
                JComboBox comboBox = (JComboBox) event.getSource();
                Object selected = comboBox.getSelectedItem();
                switch(selected.toString()){
                        //some actions based on String picked
                    default:
                    break;
                }
            }
        });

我不知道哪个参数必须有.removeActionListener（）方法来删除动作侦听器并更改comboBox的内容。

Answer 1

问题是，你已经创建了一个内联匿名内部类，这意味着你没有外部引用它......

您可以创建ActionListener，但首先将其分配给实例变量

private ActionListener actionListener;
//...
actionListener = new ActionListener() {...};
comboBox.addActionListener(actionListener);

然后您可以稍后使用...

删除它

comboBox.removeActionListener(actionListener);

Answer 2

您必须将actionListener存储在变量中：

ActionListener al = new ActionListener() {
            public void actionPerformed(ActionEvent event) {
                JComboBox comboBox = (JComboBox) event.getSource();
                Object selected = comboBox.getSelectedItem();
                switch(selected.toString()){
                        //some actions based on String picked
                    default:
                    break;
                }
            }
        }

并使用comboBox.removeActionListener(al)删除actionListener，并且必须使用al来添加侦听器

删除comboBox的actionlistener，但找不到参数

2 个答案: