Java Swing：App 的 JFrame 上鼠标 cursor 后的“永久工具提示”提示

Question

I would like to create a small tooltip-like (hint) window that will popup upon request then follow the mouse cursor anywhere on the application's JFrame until it is later destroyed. It really is a global hint message asking the user to perform a specific task (between many different windows) and once they have done so, it will disappear. For example:

GlobalToolTip panelHint = new GlobalToolTip("Global hint message.");
panelHint.show(); //Will remain visible and follow mouse
... //Waiting for user to perform a specific action or cancel
panelHint.hide(); //Hidden/destroyed here

I'm looking to either create my own class extending from JToolTip / JPanel or to override the default tooltip behavior if possible. Perhaps using the app JFrame's JLayeredPane or glassPane? I've checked a handful of other solutions but all apply to a single component's behavior only. I also tried having a JPanel on the glassPane but it wasn't being drawn properly over some of the other window contents. Perhaps I was not calling its draw methods at the correct place?

This seems like it should be a pretty easy problem to solve, but I have not been able to. Any help would be appreciated.

Answer 1

Personally, I wouldn't bother with the glassPane and I wouldn't bother with trying to make a JToolTip or the ToolTipManager do things they weren't meant to do. I would just make a JLabel that mimics a JToolTip:

import java.awt.AWTEvent;
import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.EventQueue;
import java.awt.Point;
import java.awt.Window;

import java.awt.event.MouseEvent;
import java.awt.event.AWTEventListener;

import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.JToggleButton;
import javax.swing.JWindow;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;

public class FollowTip {
    private JWindow tip;

    private final AWTEventListener mouseHandler = e -> {
        Window window = tip.getOwner();
        MouseEvent event = null;

        switch (e.getID()) {
            case MouseEvent.MOUSE_ENTERED:
            case MouseEvent.MOUSE_MOVED:
            case MouseEvent.MOUSE_DRAGGED:
                event = (MouseEvent) e;
                if (window.isAncestorOf(event.getComponent())) {
                    Point loc = event.getLocationOnScreen();
                    tip.setLocation(loc.x + 10, loc.y + 10);
                    tip.setVisible(true);
                }
                break;
            case MouseEvent.MOUSE_EXITED:
                event = (MouseEvent) e;
                Point p = SwingUtilities.convertPoint(
                    event.getComponent(), event.getPoint(), window);
                if (!window.contains(p)) {
                    tip.setVisible(false);
                }
                break;
            default:
                break;
        }
    };

    public FollowTip(String text,
                     Window window) {

        JLabel tipLabel = new JLabel(text);

        tipLabel.setForeground(UIManager.getColor("ToolTip.foreground"));
        tipLabel.setBackground(UIManager.getColor("ToolTip.background"));
        tipLabel.setFont(UIManager.getFont("ToolTip.font"));
        tipLabel.setBorder(UIManager.getBorder("ToolTip.border"));

        tip = new JWindow(window);
        tip.setType(Window.Type.POPUP);
        tip.setFocusableWindowState(false);
        tip.getContentPane().add(tipLabel);
        tip.pack();
    }

    public void activate() {
        Window window = tip.getOwner();
        window.getToolkit().addAWTEventListener(mouseHandler,
            AWTEvent.MOUSE_EVENT_MASK | AWTEvent.MOUSE_MOTION_EVENT_MASK);

        Point p = window.getMousePosition();
        if (p != null) {
            SwingUtilities.convertPointToScreen(p, window);
            tip.setLocation(p.x + 10, p.y + 10);
            tip.setVisible(true);
        }
    }

    public void deactivate() {
        Window window = tip.getOwner();
        window.getToolkit().removeAWTEventListener(mouseHandler);

        tip.setVisible(false);
    }

    static void showWindow() {
        Object[][] data = new Object[12][];
        Object[] headings = new Object[data.length];
        for (int i = 0; i < data.length; i++) {
            data[i] = new Object[data.length];
            for (int j = 0; j < data[i].length; j++) {
                data[i][j] = (i + 1) * (j + 1);
            }
            headings[i] = i;
        }

        JTable table = new JTable(data, headings);

        JToggleButton button = new JToggleButton("Active");
        JPanel buttonPanel = new JPanel();
        buttonPanel.add(button);

        JFrame frame = new JFrame("FollowTip");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.getContentPane().add(new JScrollPane(table));
        frame.getContentPane().add(buttonPanel, BorderLayout.PAGE_END);
        frame.pack();
        frame.setLocationByPlatform(true);
        frame.setVisible(true);

        FollowTip tip = new FollowTip("This is a tip", frame);

        button.addActionListener(e -> {
            if (button.isSelected()) {
                tip.activate();
            } else {
                tip.deactivate();
            }
        });
    }

    public static void main(String[] args) {
        EventQueue.invokeLater(() -> showWindow());
    }
}