我有一个扩展 JPanel 的类:

public class ButtonPanel extends JPanel {

    private label;

    public ButtonPanel() {
        label=new JLabel("waiting for click");
        add(label);
    }

    public void setButtonText() {
        label.setText("just clicked");
    }

}

我有几个该类的实例被添加到 JFrame 中。我想创建一个 MouseAdapter 类实例，然后将它们作为鼠标监听器添加到我的 JFrame 上的所有 ButtonPanel 组件。我是说:

ButtonPanel butt1 = new ButtonPanel();
ButtonPanel butt2 = new ButtonPanel();
ButtonPanel butt3 = new ButtonPanel();
//... here goes code which add ButtonPanels to JFrame

MouseAdapterMod mam = new MouseAdapterMod();
butt1.addMouseListener(mam);
butt2.addMouseListener(mam);
butt3.addMouseListener(mam);

我想将 MouseAdapterMod 类与其他类分开并放在它自己的包中。它应该看起来像这样:

public class MouseAdapterMod extends MouseAdapter {

    public void mouseClicked(MouseEvent e) {
        //here goes the code of calling setButtonText method of ButtonPanel component on which the event had occurred
    }
}

所以问题是我不知道如何实现 mouseClicked 方法以使其确定哪个 ButtonPanel 生成事件并调用对应于该组件的 setButtonText() 方法。有人知道怎么做吗？

我知道我可以通过在 ButtonPanel 类中包含事件处理功能来实现这一点，但这对我来说不合适，因为我想保留上面描述的类结构并且只有一个 MouseAdapterMod 类实例用于处理所有的 ButtonPanel。

最佳答案

MouseEvent#getSource 方法将返回哪个对象被点击:

public class MouseAdapterMod extends MouseAdapter {

   // usually better off with mousePressed rather than clicked
   public void mousePressed(MouseEvent e) {
       ButtonPanel btnPanel = (ButtonPanel)e.getSource();
       btnPanel.setButtonText();
   }
}

如评论所述，您通常最好听 mousePressed 或 mouseReleased 而不是 mouseClicked，因为要使 mouseClicked 起作用，按下和释放必须来自同一点，并且如果鼠标稍微移动一点，点击不会注册。

我的测试程序:

import java.awt.Color;
import java.awt.GridLayout;
import java.awt.event.*;

import javax.swing.*;

public class MainForButtonPanel extends JPanel {
   public MainForButtonPanel() {
      setLayout(new GridLayout(4, 4));

      MouseAdapter myMA = new MouseAdapterMod();

      for (int i = 0; i < 4; i++) {
         for (int j = 0; j < 4; j++) {
            ButtonPanel btnPanel = new ButtonPanel();
            btnPanel.addMouseListener(myMA);
            add(btnPanel);
         }
      }

   }

   private static void createAndShowUI() {
      JFrame frame = new JFrame("MainForButtonPanel");
      frame.getContentPane().add(new MainForButtonPanel());
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      frame.pack();
      frame.setLocationRelativeTo(null);
      frame.setVisible(true);
   }

   public static void main(String[] args) {
      java.awt.EventQueue.invokeLater(new Runnable() {
         public void run() {
            createAndShowUI();
         }
      });
   }
}

class ButtonPanel extends JPanel {

   private static final int TIMER_DELAY = 2000;
   private static final String JUST_CLICKED = "just clicked";
   private static final String WAITING_FOR_CLICK = "waiting for click";
   private static final Color CLICKED_COLOR = Color.pink;
   private JLabel label;

   public ButtonPanel() {
      label = new JLabel(WAITING_FOR_CLICK);
      add(label);
   }

   public void setButtonText() {
      label.setText(JUST_CLICKED);
      setBackground(CLICKED_COLOR);

      new Timer(TIMER_DELAY, new ActionListener() {
         public void actionPerformed(ActionEvent ae) {
            label.setText(WAITING_FOR_CLICK);
            setBackground(null);
            ((Timer)ae.getSource()).stop();
         }
      }).start();
   }

}

class MouseAdapterMod extends MouseAdapter {

   // usually better off with mousePressed rather than clicked
   public void mousePressed(MouseEvent e) {
       ButtonPanel btnPanel = (ButtonPanel)e.getSource();
       btnPanel.setButtonText();
   }
}

关于java - 在 MouseListener 中确定单击的 JPanel 组件。事件处理，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/7340001/