Question

这是我的问题：

enter image description here

我基本上是在右键单击JTree中的元素时创建一个下拉菜单，问题是JTree在JScrollPane内部，窗格滚动得越多，弹出菜单就越远了。

右键单击会触发一个MouseEvent，它会在以下代码中被拦截，其结果是创建一个新的弹出菜单。

@Override
public void mouseClicked(MouseEvent e) {
    if (SwingUtilities.isRightMouseButton(e)) {

        int row = tree.getClosestRowForLocation(e.getX(), e.getY());
        tree.setSelectionRow(row);

        TreePath path = tree.getPathForRow(row);  

        DefaultMutableTreeNode node = (DefaultMutableTreeNode) path.getLastPathComponent();  

        // If this object is a Search...
        if(node.getUserObject().getClass() == Search.class) {
            jp = new ItemEditPopUpMenu(tree, row, true);
        } else {
            jp = new ItemEditPopUpMenu(tree, row, false);
        }

        jp.show(this, e.getX(), e.getY());
    }
}

正如您所看到的，我正在做的就是从MouseEvent抓取位置并将其用作在以下行中创建弹出菜单的位置：

jp.show(this, e.getX(), e.getY());

现在引起我的注意，这是发送事件的元素的相对位置，这解释了问题，JScrollPanel在滚动时从JFrame偏移，问题是如何判断如何多远？

我只是不知道，这就是我需要帮助的地方。非常感谢提前！

Answer 1

我似乎没有问题。

如果我使用视口“视图”作为弹出窗口的参考，弹出窗口会准确显示鼠标点击的位置。

我只能想象你没有将对树的引用传递给弹出窗口......

enter image description here

我认为这将是一个混乱的点转换，但事实证明，它很简单，因为可以......

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Point;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.util.ArrayList;
import java.util.List;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JPopupMenu;
import javax.swing.JScrollPane;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;

public class TestScrollPane {

    public static void main(String[] args) {
        new TestScrollPane();
    }

    public TestScrollPane() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                }

                JFrame frame = new JFrame("Testing");
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.setLayout(new BorderLayout());
                frame.add(new JScrollPane(new TestPane()));
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

    public class TestPane extends JPanel {

        private List<Point> points;
        private JPopupMenu pm;

        public TestPane() {
            pm = new JPopupMenu();
            pm.add(new JLabel("Suprise"));
            points = new ArrayList<>(3);
            addMouseListener(new MouseAdapter() {
                @Override
                public void mouseClicked(MouseEvent e) {
                    Point p = e.getPoint();
                    points.clear();
                    points.add(p);
                    // View port
                    Container parent = getParent();
                    Point pp = SwingUtilities.convertPoint(TestPane.this, p, parent);
                    points.add(pp);
                    // ScrollPane...
                    parent = parent.getParent();
                    Point ppp = SwingUtilities.convertPoint(TestPane.this, p, parent);
                    points.add(ppp);

                    pm.show(TestPane.this, p.x, p.y);

                    repaint();
                }
            });
        }

        @Override
        public Dimension getPreferredSize() {
            return new Dimension(1000, 1000);
        }

        @Override
        protected void paintComponent(Graphics g) {
            super.paintComponent(g);
            Graphics2D g2d = (Graphics2D) g.create();
            if (points.size() == 3) {
                g2d.setColor(Color.RED);
                Point p = points.get(0);
                g2d.fillOval(p.x - 2, p.y - 2, 4, 4);

                g2d.setColor(Color.GREEN);
                p = points.get(1);
                g2d.fillOval(p.x - 2, p.y - 2, 4, 4);

                g2d.setColor(Color.BLUE);
                p = points.get(2);
                g2d.fillOval(p.x - 2, p.y - 2, 4, 4);
            }
            g2d.dispose();
        }
    }
}

为了确保我没有遗漏某些内容，这是使用JTree

的版本

enter image description here

（您可以放弃自定义单元格渲染进行测试，这是我放置的一些废弃代码）

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Component;
import java.awt.EventQueue;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.io.IOException;
import java.util.Random;
import javax.imageio.ImageIO;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JPopupMenu;
import javax.swing.JScrollPane;
import javax.swing.JTree;
import javax.swing.UIManager;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.DefaultTreeCellRenderer;
import javax.swing.tree.DefaultTreeModel;

public class TestCustomTreeNode {

    public static void main(String args[]) {
        new TestCustomTreeNode();
    }
    private JPopupMenu pm;

    public TestCustomTreeNode() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (Exception ex) {
                }

                pm = new JPopupMenu();
                pm.add(new JLabel("Suprise"));

                JFrame f = new JFrame("JTree Sample");
                f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

                JPanel pnlMain = new JPanel(new BorderLayout());
                pnlMain.setBackground(Color.white);

                createTree(pnlMain);

                f.setContentPane(new JScrollPane(pnlMain));

                f.setSize(300, 200);
                f.setVisible(true);
            }
        });
    }

    private void createTree(JPanel pnlMain) {
        Employee bigBoss = new Employee(Employee.randomName(), true);
        Employee[] level1 = new Employee[5];
        bigBoss.employees = level1;

        for (int i = 0; i < level1.length; i++) {
            level1[i] = new Employee(Employee.randomName(), true);
        }


        for (int i = 0; i < level1.length; i++) {
            Employee employee = level1[i];
            if (employee.isBoss) {
                int count = 5;
                employee.employees = new Employee[count];

                for (int j = 0; j < employee.employees.length; j++) {
                    employee.employees[j] = new Employee(Employee.randomName(), false);
                }
            }
        }

        CustomTreeNode root = new CustomTreeNode(loadResource("/pirate.png"), bigBoss);
        root.setUserObject("Root");
        DefaultTreeModel model = new DefaultTreeModel(root);

        for (Employee employee : bigBoss.employees) {
            CustomTreeNode boss = new CustomTreeNode(loadResource("/angel.png"), employee);
            root.add(boss);
            if (employee.isBoss) {
                for (Employee employee1 : employee.employees) {
                    CustomTreeNode emp = new CustomTreeNode(loadResource("/devil.png"), employee1);
                    boss.add(emp);
                }
            }
        }

        JTree tree = new JTree(model);
        tree.setCellRenderer(new CustomeTreeCellRenderer());
        pnlMain.add(tree, BorderLayout.CENTER);

        tree.addMouseListener(new MouseAdapter() {
            @Override
            public void mouseReleased(MouseEvent e) {
                if (e.isPopupTrigger()) {
                    pm.show(e.getComponent(), e.getX(), e.getY());
                }
            }
        });

    }

    protected ImageIcon loadResource(String name) {

        ImageIcon image = null;
        try {
            image = new ImageIcon(ImageIO.read(getClass().getResource(name)));
            System.out.println(name + " - " + image);
        } catch (IOException ex) {
            ex.printStackTrace();
        }

        return image;

    }

    public static class Employee {

        public String name;
        public int id;
        public boolean isBoss;
        public Employee[] employees;

        public Employee(String name, boolean isBoss) {
            this.name = name;
            this.isBoss = isBoss;
            this.id = new Random(System.currentTimeMillis()).nextInt(Integer.MAX_VALUE);
        }

        @Override
        public String toString() {
            return this.name;
        }

        static String randomName() {
            String chars = "abcdefghijklmnopqrstuvwxyz";
            StringBuilder builder = new StringBuilder();
            Random r = new Random(System.currentTimeMillis());
            int length = r.nextInt(10) + 1;
            for (int i = 0; i < length; i++) {
                builder.append(chars.charAt(r.nextInt(chars.length())));
            }

            return builder.toString();
        }
    }

    public class CustomTreeNode extends DefaultMutableTreeNode {

        /**
         * The icon which is displayed on the JTree object. open, close, leaf icon.
         */
        private ImageIcon icon;

        public CustomTreeNode(ImageIcon icon) {
            this.icon = icon;
        }

        public CustomTreeNode(ImageIcon icon, Object userObject) {
            super(userObject);
            this.icon = icon;
        }

        public CustomTreeNode(ImageIcon icon, Object userObject, boolean allowsChildren) {
            super(userObject, allowsChildren);
            this.icon = icon;
        }

        public ImageIcon getIcon() {
            return icon;
        }

        public void setIcon(ImageIcon icon) {
            this.icon = icon;
        }
    }

    class CustomeTreeCellRenderer extends DefaultTreeCellRenderer {

        public CustomeTreeCellRenderer() {
        }

        @Override
        public Component getTreeCellRendererComponent(JTree tree, Object value, boolean selected, boolean expanded, boolean leaf, int row, boolean hasFocus) {

//            if (!leaf) {
            CustomTreeNode node = (CustomTreeNode) value;

            if (node.getIcon() != null) {
                System.out.println(node + " - " + node.getIcon());
                setClosedIcon(node.getIcon());
                setOpenIcon(node.getIcon());
                setLeafIcon(node.getIcon());
            } else {
                System.out.println(node + " - default");
                setClosedIcon(getDefaultClosedIcon());
                setLeafIcon(getDefaultLeafIcon());
                setOpenIcon(getDefaultOpenIcon());
            }
//            }

            super.getTreeCellRendererComponent(tree, value, selected, expanded, leaf, row, hasFocus);

            return this;
        }
    }
}

nb：您可能需要更改鼠标事件，因为不同平台的弹出触发器可能不同，这在Windows上运行正常

由此，我只能得出结论，您传递给JPopupMenu#show的组件引用不是生成鼠标事件的组件引用。

Answer 2

我用过：

PointerInfo a = MouseInfo.getPointerInfo();
Point b = a.getLocation();
SwingUtilities.convertPointFromScreen(b, component);

组件是我的JTree。这似乎抓住了鼠标的屏幕位置并使用了一个隐藏在Swing中的转换实用程序功能来使其运行起来。希望这可以帮助别人！

Answer 3

这可能不是一个好的解决方案，但它可以解决您的问题。

这里的问题是当你说e.getX()或e.getY()时，返回的坐标是相对于JTree的。从给定的屏幕截图中我可以看到，你已经向下滚动了JTree，你需要从“Y”坐标中减去垂直滚动条值的差异。

int verticalScrollValue = scrollPane.getVerticalScrollBar().getValue();
jp.show(this, e.getX(), e.getY() - verticalScrollValue);

Answer 4

我的问题是逐字，JTree等等。虽然我发现接受的答案很有用，但仍需要进行一些挖掘才能弄清楚错误是什么以及解决方案是什么样的。

问题，这是问题代码的样子：

final Component parent = ...
final JTree tree = ...
final JPopupMenu menu = ...

parent.add(tree);

tree.addMouseListener(new MouseAdapter() {
    @Override
    public void mousePressed(MouseEvent e) {
        if (e.getButton() == MouseEvent.BUTTON3) // Right click
            menu.show(parent, e.getX(), e.getY());
    }
});

错误现在应该很明显了！

MouseEvent由tree从添加的MouseListener生成，但我们将parent作为invoker传递给menu.show(...)。这会在屏幕截图中产生不良行为。

修复方法是将tree作为invoker传递给menu.show(...)，如下所示：

final Component parent = ...
final JTree tree = ...
final JPopupMenu menu = ...

parent.add(tree);

tree.addMouseListener(new MouseAdapter() {
    @Override
    public void mousePressed(MouseEvent e) {
        if (e.getButton() == MouseEvent.BUTTON3) // Right click
            menu.show(tree, e.getX(), e.getY());
    }
});

在JScrollPane中获取正确的鼠标位置

4 个答案: