Question

我有一个类whitch扩展JPanel：

public class ButtonPanel extends JPanel {

    private label;

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

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

}

我有几个添加到JFrame的类的实例。我想创建一个MouseAdapter类的实例，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：

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);

MouseAdapterMod类我希望与另一个分开并找到它自己的包中。它应该是这样的：

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方法来确定哪个ButtonPanel生成事件并调用对应的那个组件setButtonText（）方法。有谁知道怎么做？

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ButtonPanels。

Answer 1

MouseEvent#getSource方法将返回单击的对象：

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();
   }
}

正如评论所指出的那样，你通常最好不要听mousePressed或mouseReleased而不是mouseClicked，因为要鼠标点击工作，按下和释放必须来自同一点，如果鼠标移动了一点点，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();
   }
}

确定MouseListener中单击的JPanel组件。事件处理

1 个答案: