概念

对鼠标、键盘等一系列事件做出相应的反馈

• 事件监听

  //创建监听事件
  public class Demo {
  public static void main(String[] args) {
  Frame frame = new Frame();
  frame.setLayout(new FlowLayout(FlowLayout.CENTER));
  Button button = new Button("start");

      //添加监听器
      //根据参数我们可以知道需要添加一个监听器类，所以需要什么，我们就new什么
      MyListener myListener = new MyListener();
      button.addActionListener(myListener);
  frame.add(button);
  windowClose(frame);
  frame.pack();//自动控制大小
  frame.setVisible(true);
  }
  
  //实现关闭窗口监听
  private static void windowClose(Frame frame) {
      frame.addWindowListener(new WindowAdapter() {
          @Override
          public void windowClosing(WindowEvent windowEvent) {
              System.exit(0);
          }
      });
  }
  
  static class MyListener implements ActionListener {
  @Override
  public void actionPerformed(ActionEvent actionEvent) {
      System.out.println("产生事件响应...");
  }
  }

  }

• 多事件监听

  public class Demo01 {
  public static void main(String[] args) {
  Frame frame = new Frame();
  Button btn1 = new Button("btn1");
  Button btn2 = new Button("btn2");

      //设置监听
      MyListener myListener = new MyListener();
      btn1.setActionCommand("btn1");
      btn2.setActionCommand("btn2");
      btn1.addActionListener(myListener);
      btn2.addActionListener(myListener);
  frame.setLayout(new GridLayout(1,2));
  frame.add(btn1);
  frame.add(btn2);
  frame.pack();
  frame.setVisible(true);
  }
  
  //实现共同监听事件
  static class MyListener implements ActionListener{
  @Override
  public void actionPerformed(ActionEvent actionEvent) {
      System.out.println(actionEvent.getActionCommand()+"发出响应。");
      //通过监听事件返回值，判断
      if (actionEvent.getActionCommand().equals("btn1")){
          System.out.println("start");
      }
  }
  }

  }

常用监听：

一、文本监听 textField()

public class TextListener {
    public static void main(String[] args) {
        TextFrame textFrame = new TextFrame("文本测试窗口");

        //新建文本框
        TextField textField = new TextField();

        textFrame.add(textField,BorderLayout.CENTER);
        textFrame.setVisible(true);
    }

}

//将窗口类封装
class TextFrame extends Frame{
    public TextFrame(String title){
        super(title);
        this.setBounds(200,200,500,400);
    }
}

二、鼠标监听

public class MouseListener {
    public static void main(String[] args) {
        mouseFrame frame = new mouseFrame("鼠标监听测试窗口");

        //添加鼠标监听
        frame.addMouseListener(new myMouse());

        frame.setVisible(true);
    }
}

//适配器模式
class myMouse extends MouseAdapter{
    @Override
    public void mouseClicked(MouseEvent mouseEvent) {
        System.out.println("点击");
        //获取鼠标位置
        System.out.println("鼠标位置为("+mouseEvent.getX()+","+mouseEvent.getY()+")");
    }
}

class mouseFrame extends Frame{
    public mouseFrame(String title){
        super(title);
        this.setBounds(200,200,500,400);
    }
}

三、窗口监听

//实现窗口监听
class windowClose extends WindowAdapter{
    @Override
    public void windowClosing(WindowEvent windowEvent) {
        System.exit(0);
    }
}

补充：适配器模式的作用，个人理解为避免实现不必要的接口方法，即只想实现接口的其中几个方法，采用一个实现所有接口的类（适配器），通过继承这个适配器来实现（重载）某个方法。