在视口组件上使用 JScrollPane 鼠标侦听器

我有一个JScrollPane可以设置其视口View到一系列不同的面板。我想在单击其视口中的任何其他组件时获取 JScrollPane 组件。如果我添加一个MouseListener对于 JScrollPane，当我直接单击窗格边框时，它会接收鼠标事件，但当我单击组件时，它不会接收鼠标事件。

添加侦听器并最终找到封闭的滚动窗格的正确方法是什么？我不一定会提前知道在视口中显示的面板上的所有组件 - 只是它们将位于 JPanel 的某个子类上。

import java.awt.event.MouseEvent;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.event.MouseInputAdapter;

import net.miginfocom.swing.MigLayout;

public class TestScrollPane extends MouseInputAdapter{
    public void mouseEntered(MouseEvent arg0) {System.out.println("Entered " + arg0.getComponent());}
    public void mouseExited(MouseEvent arg0) {System.out.println("Exited " + arg0.getComponent());}
    public void mousePressed(MouseEvent arg0) {System.out.println("Pressed " + arg0.getComponent());}
    public void mouseReleased(MouseEvent arg0) {System.out.println("Released " + arg0.getComponent());}

    public static void main(String[] args){
        JFrame frame = new JFrame();
        frame.setLayout(new MigLayout());
        frame.setSize(400, 400);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        TestPane pane1 = new TestPane("Scroll Pane 1");
        TestPane pane2 = new TestPane("Scroll Pane 2");
        frame.add(pane1, "push,grow");
        frame.add(pane2, "push, grow");
        TestMouseListener listener = new TestMouseListener();
        pane1.addMouseListener(listener);
        pane1.addMouseMotionListener(listener);
        pane2.addMouseListener(listener);
        pane2.addMouseMotionListener(listener);
        frame.setVisible(true);
    }
}

class TestPanel2 extends JPanel {
    String name;
    TestPanel2(String name){ 
        this.name = name;
        setLayout(new MigLayout());
        JTextArea area = new JTextArea();
        area.append(name);
        add(area, "push, grow");
    }
    public String toString(){ return name; }
}
class TestPane extends JScrollPane {
    String name;
    TestPane(String name){ 
        this.name = name; 
        TestPanel2 panel = new TestPanel2(name + " panel");
        setViewportView(panel);
    }
    public String toString(){ return name; }
}

在此示例中，我获取了鼠标进入和退出事件，但我只能通过单击文本区域周围的边框来获取鼠标单击事件。即使我更改 TestPane 类以将侦听器添加到其 viewportView 面板，我也无法判断 textArea 中发生了什么。

class TestPane extends JScrollPane {
    String name;
    TestPane(String name){ 
        this.name = name; 
        TestPanel2 panel = new TestPanel2(name + " panel");
        TestMouseListener listener = new TestMouseListener();
        panel.addMouseListener(listener);
        panel.addMouseMotionListener(listener);
        setViewportView(panel);
    }
    public String toString(){ return name; }
}

不过，我无法知道 JPanel 上有什么，因此我无法更深入地手动添加侦听器。

另一种可能的方法是使用 AWTEventListener，然后向上冒泡父树以查看您感兴趣的组件是否已被按下或包含已按下的子组件。例如：

import java.awt.AWTEvent;
import java.awt.Component;
import java.awt.FlowLayout;
import java.awt.Toolkit;
import java.awt.event.AWTEventListener;
import java.awt.event.MouseEvent;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.event.MouseInputAdapter;

// import net.miginfocom.swing.MigLayout;

public class TestScrollPane extends MouseInputAdapter {
   public void mouseEntered(MouseEvent arg0) {
      System.out.println("Entered " + arg0.getComponent());
   }

   public void mouseExited(MouseEvent arg0) {
      System.out.println("Exited " + arg0.getComponent());
   }

   public void mousePressed(MouseEvent arg0) {
      System.out.println("Pressed " + arg0.getComponent());
   }

   public void mouseReleased(MouseEvent arg0) {
      System.out.println("Released " + arg0.getComponent());
   }

   public static void main(String[] args) {
      JFrame frame = new JFrame();
      // frame.setLayout(new MigLayout());
      frame.getContentPane().setLayout(new FlowLayout());
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      TestPane pane1 = new TestPane("Scroll Pane 1");
      TestPane pane2 = new TestPane("Scroll Pane 2");
      frame.add(pane1, "push,grow");
      frame.add(pane2, "push, grow");
      // !! TestMouseListener listener = new TestMouseListener();
      TestScrollPane listener = new TestScrollPane();
      pane1.addMouseListener(listener);
      pane1.addMouseMotionListener(listener);
      pane2.addMouseListener(listener);
      pane2.addMouseMotionListener(listener);
      frame.pack();
      frame.setVisible(true);

      Toolkit.getDefaultToolkit().addAWTEventListener(
            listener.createAWTWindowListener(), AWTEvent.MOUSE_EVENT_MASK);

   }

   private AWTEventListener createAWTWindowListener() {
      AWTEventListener awt1 = new AWTEventListener() {

         @Override
         public void eventDispatched(AWTEvent e) {
            if (MouseEvent.MOUSE_PRESSED == e.getID()) {
               MouseEvent event = (MouseEvent) e;
               Component comp = event.getComponent();

               if (comp != null) {
                  String scrollPanelName = recursivelyCheckForScrollPanel(comp);
                  if (scrollPanelName != null) {
                     System.out.println("TestPane pressed. Name: " + scrollPanelName);
                  } else {
                     System.out.println("TestPane not pressed");
                  }
               }
            }
         }

         private String recursivelyCheckForScrollPanel(Component comp) {
            if (comp instanceof TestPane) {
               return comp.toString();
            } else {
               comp = comp.getParent();
               if (comp != null) {
                  return recursivelyCheckForScrollPanel(comp);
               }
            }
            return null;
         }
      };
      return awt1;
   }
}

class TestPanel2 extends JPanel {
   String name;

   TestPanel2(String name) {
      this.name = name;
      // setLayout(new MigLayout());
      JTextArea area = new JTextArea(5, 20);
      area.append(name);
      add(area, "push, grow");
   }

   public String toString() {
      return name;
   }
}

class TestPane extends JScrollPane {
   String name;

   TestPane(String name) {
      this.name = name;
      TestPanel2 panel = new TestPanel2(name + " panel");
      setViewportView(panel);
   }

   public String toString() {
      return name;
   }
}

注：请参阅这个问题以及 StanislovL 和 mkorbel 的回答以获取更多相关信息。