java - 如何在java中将actionListener添加为单独的类

Question

我一直在研究一个程序，我的大部分代码的大师班有超过 20 种不同的“addActionListener”方法。我怎样才能在一个单独的类中创建这个 actionListener、itemStateChanged 等，但仍然按照它现在的方式执行。任何提示都会受到欢迎，因为我已经在这门课上运行了 4000 多行代码:( 谢谢！

Answer 1

public class MyActionListener implements ActionListener {
    @Override
    public void actionPerformed(ActionEvent evt) {
        // actionPerformed here...
    }
}

你会像这样使用它：

JButton button = new JButton();
button.addActionListener(new MyActionListener());

// OR

MyActionListener listener = new MyActionListener();
JButton button = new JButton();
button.addActionListener(listener);

Answer 2

class Mylistener implements ActionListener {

    @Override
    public void actionPerformed(ActionEvent e){
         if (e.getSource() == someButton){
             // do something
         } else if (e.getSource() == someOtherButton){
             // do something
         } 
         // add more else if statements for other components
         // e.getSource() is the component that fires the event e.g. someButton
    }
}

假设你有两个按钮

JButton someButton = new JButton("SOME BUTTON");
JButton someOtherButton = new JButtton("SOME OTHER BUTTON");

ActionListener listener = new MyListener();

someButton.addActionListener(listener);
someOtherButton.addActionListener(listener);

编辑：

public MyClass extends JFrame {

    JButton someButton = new JButton("SOME BUTTON");
    JButton someOtherButton = new JButtton("SOME OTHER BUTTON");

    public MyClass(){

        ActionListener listener = new MyListener();
        someButton.addActionListener(listener);
        someOtherButton.addActionListener(listener);
    }

    class Mylistener implements ActionListener {

    @Override
    public void actionPerformed(ActionEvent e){
         if (e.getSource() == someButton){
             // do something
         } else if (e.getSource() == someOtherButton){
             // do something
         } 
         // add more else if statements for other components
         // e.getSource() is the component that fires the event e.g. someButton
    }
}

Answer 3

您想编写一个实现 ActionListener 的类。我可以在这里给你一些代码，几乎不用解释，但我认为我最好将你指向这里的文档：http: //docs.oracle.com/javase/tutorial/uiswing/events/actionlistener.html

这个链接会给你一些例子，它会详细解释它是如何工作的。我希望这有帮助。