java - Java 简单 ActionListener 问题

Question

我在一个程序中有一个主类，它启动另一个处理所有 GUI 内容的类。在 GUI 中，我有一个需要附加 ActionListener 的按钮。

唯一的问题是，要执行的代码需要驻留在主类中。

当在别处单击按钮时，如何让 ActionPerformed() 方法在主类中执行？

Answer 1

使您的控制器（“主”类）实现 ActionListener 接口，然后将引用传递给视图类：

public class View extends JFrame {
  public View(final ActionListener listener) {
   JButton button = new JButton("click me");
   button.addActionListener(listener);
   button.setActionCommand("do_stuff");

   getContentPane().add(button);

   pack();
   setVisible(true);
  }
 }

 public class Control implements ActionListener {

  public Control() {
   new View(this);
  }

  @Override
  public void actionPerformed(ActionEvent e) {
   if (e.getActionCommand().equals("do_stuff")) {
    // respond to button click
   }
  }
 }

也可以使用Actions来完成，但在您希望一段代码响应多个按钮的情况下，这更有用。

Answer 2

Implement an anonymous inner class as ActionListener on the button, then call the method on your main class. This creates less dependencies and avoids the tag & switch style programming that implementing the ActionListener interface on a main class tends to promote.

In either case it will create a cycle in your dependency graph: the main class will know about the button and the button will need to call the main class. This might not be a good idea since it will make it hard to compose things in any other way. But without further information it is hard to judge the situation or recommend anything concrete.

Answer 3

在主类中实现 ActionListener 并将主类实例添加为 GUI 按钮上的侦听器。