Java Swing : Can the mouse make changes to two overlayed JPanels at the same time?

Question

我是 swing 新手，遇到以下问题:

我正在使用 openslide-java 库来查看整个幻灯片图像。有一个名为 OpenSlideView 的类扩展了 JPanel，其目的是查看图像。此类具有使用鼠标放大、缩小和浏览图像的功能，因为它使用自己的鼠标监听器。我在 JFrame 中叠加两个 OpenSlideView 对象，其中一个可见，另一个不可见，并且我希望能够同时对它们执行鼠标操作，即使其中一个不可见。简单地说，我希望不可见的 JPanel 能够追踪鼠标。

这样的事情可能吗？即使是 JPanel 类而不是它的扩展？

提前致谢。

P.S:我附上了处理 OpenSlideView 对象鼠标事件的方法的代码，以防有帮助。

   private void registerEventHandlers() {
    // mouse wheel
    addMouseWheelListener(new MouseWheelListener() {
        public void mouseWheelMoved(MouseWheelEvent e) {
            double ds1 = zoomHelper(OpenSlideView.this, e.getX(), e.getY(),
                    e.getWheelRotation());
            double ds2 = zoomHelper(otherView, e.getX(), e.getY(), e
                    .getWheelRotation());
            zoomHelper2(OpenSlideView.this, ds1, e.getX(), e.getY());
            zoomHelper2(otherView, ds2, e.getX(), e.getY());
            zoomHelper3(OpenSlideView.this, ds1);
            zoomHelper3(otherView, ds2);
            repaintHelper(OpenSlideView.this);
            repaintHelper(otherView);
        }
    });

    // mouse drag
    MouseAdapter ma = new MouseAdapter() {
        private SelectionMode selectionMode;

        private int oldX;

        private int oldY;

        private int slideStartX;

        private int slideStartY;

        private Path2D.Double freehandPath;

        @Override
        public void mousePressed(MouseEvent e) {
            // System.out.println(e);

            requestFocusInWindow();

            if (!SwingUtilities.isLeftMouseButton(e)) {
                return;
            }

            final int ellipseMask = MouseEvent.CTRL_DOWN_MASK
                    | MouseEvent.SHIFT_DOWN_MASK;
            final int freehandMask = MouseEvent.CTRL_DOWN_MASK;
            final int rectMask = MouseEvent.SHIFT_DOWN_MASK;

            if ((e.getModifiersEx() & ellipseMask) == ellipseMask) {
                selectionMode = SelectionMode.ELLIPSE;
            } else if ((e.getModifiersEx() & freehandMask) == freehandMask) {
                selectionMode = SelectionMode.FREEHAND;
            } else if ((e.getModifiersEx() & rectMask) == rectMask) {
                selectionMode = SelectionMode.RECT;
            } else {
                selectionMode = SelectionMode.NONE;
            }

            oldX = e.getX();
            oldY = e.getY();

            double ds = getDownsample();
            slideStartX = (int) ((oldX + viewPosition.x) * ds);
            slideStartY = (int) ((oldY + viewPosition.y) * ds);
        }

        @Override
        public void mouseDragged(MouseEvent e) {
            if (!SwingUtilities.isLeftMouseButton(e)) {
                return;
            }

            int relX = oldX - e.getX();
            int relY = oldY - e.getY();

            double ds = getDownsample();
            int dx = slideStartX;
            int dy = slideStartY;
            int dw = (int) ((e.getX() + viewPosition.x) * ds) - dx;
            int dh = (int) ((e.getY() + viewPosition.y) * ds) - dy;

            if (dw < 0) {
                dx += dw;
                dw = -dw;
            }
            if (dh < 0) {
                dy += dh;
                dh = -dh;
            }

            switch (selectionMode) {
            case NONE:
                translateHelper(OpenSlideView.this, relX, relY);
                translateHelper(otherView, relX, relY);
                repaintHelper(OpenSlideView.this);
                repaintHelper(otherView);
                break;

            case RECT:
                selectionBeingDrawn = new Rectangle(dx, dy, dw, dh);
                // System.out.println(selection);
                repaint();
                break;

            case FREEHAND:
                if (selectionBeingDrawn == null) {
                    // new selection
                    freehandPath = new Path2D.Double();
                    selectionBeingDrawn = freehandPath;

                    freehandPath.moveTo(slideStartX, slideStartY);
                }

                freehandPath.lineTo((e.getX() + viewPosition.x) * ds, (e
                        .getY() + viewPosition.y)
                        * ds);

                repaint();
                break;

            case ELLIPSE:
                selectionBeingDrawn = new Ellipse2D.Double(dx, dy, dw, dh);

                repaint();
                break;
            }
            oldX = e.getX();
            oldY = e.getY();
        }

        @Override
        public void mouseReleased(MouseEvent e) {
            if (selectionMode == SelectionMode.FREEHAND) {
                freehandPath.closePath();
            }
            selectionMode = SelectionMode.NONE;

            if (selectionBeingDrawn != null) {
                Rectangle bb = selectionBeingDrawn.getBounds();
                if (bb.height != 0 && bb.width != 0) {
                    selections.add(new DefaultAnnotation(selectionBeingDrawn));
                    selectionBeingDrawn = null;
                }
            }
            repaint();
        }

        @Override
        public void mouseEntered(MouseEvent e) {
            selectionsVisibleHelper(OpenSlideView.this, true);
            selectionsVisibleHelper(otherView, true);
        }

        @Override
        public void mouseExited(MouseEvent e) {
            selectionsVisibleHelper(OpenSlideView.this, false);
            selectionsVisibleHelper(otherView, false);
        }
    };
    addMouseListener(ma);
    addMouseMotionListener(ma);

    // keyboard
    InputMap inputMap = new InputMap();
    ActionMap actionMap = new ActionMap();

    inputMap.put(KeyStroke.getKeyStroke("SPACE"), "center");
    actionMap.put("center", new AbstractAction() {
        public void actionPerformed(ActionEvent e) {
            centerHelper(OpenSlideView.this);
            centerHelper(otherView);
            repaintHelper(OpenSlideView.this);
            repaintHelper(otherView);
        }
    });

    inputMap.put(KeyStroke.getKeyStroke("UP"), "scroll up");
    inputMap.put(KeyStroke.getKeyStroke("W"), "scroll up");
    actionMap.put("scroll up", new AbstractAction() {
        public void actionPerformed(ActionEvent e) {
            translateHelper(OpenSlideView.this, 0, -KEYBOARD_SCROLL_AMOUNT);
            translateHelper(otherView, 0, -KEYBOARD_SCROLL_AMOUNT);
            repaintHelper(OpenSlideView.this);
            repaintHelper(otherView);
        }
    });

    inputMap.put(KeyStroke.getKeyStroke("DOWN"), "scroll down");
    inputMap.put(KeyStroke.getKeyStroke("S"), "scroll down");
    actionMap.put("scroll down", new AbstractAction() {
        public void actionPerformed(ActionEvent e) {
            translateHelper(OpenSlideView.this, 0, KEYBOARD_SCROLL_AMOUNT);
            translateHelper(otherView, 0, KEYBOARD_SCROLL_AMOUNT);
            repaintHelper(OpenSlideView.this);
            repaintHelper(otherView);
        }
    });

    inputMap.put(KeyStroke.getKeyStroke("LEFT"), "scroll left");
    inputMap.put(KeyStroke.getKeyStroke("A"), "scroll left");
    actionMap.put("scroll left", new AbstractAction() {
        public void actionPerformed(ActionEvent e) {
            translateHelper(OpenSlideView.this, -KEYBOARD_SCROLL_AMOUNT, 0);
            translateHelper(otherView, -KEYBOARD_SCROLL_AMOUNT, 0);
            repaintHelper(OpenSlideView.this);
            repaintHelper(otherView);
        }
    });

    inputMap.put(KeyStroke.getKeyStroke("RIGHT"), "scroll right");
    inputMap.put(KeyStroke.getKeyStroke("D"), "scroll right");
    actionMap.put("scroll right", new AbstractAction() {
        public void actionPerformed(ActionEvent e) {
            translateHelper(OpenSlideView.this, KEYBOARD_SCROLL_AMOUNT, 0);
            translateHelper(otherView, KEYBOARD_SCROLL_AMOUNT, 0);
            repaintHelper(OpenSlideView.this);
            repaintHelper(otherView);
        }
    });

    inputMap.put(KeyStroke.getKeyStroke("L"), "rotate left");
    actionMap.put("rotate left", new AbstractAction() {
        public void actionPerformed(ActionEvent e) {

        }
    });

    inputMap.put(KeyStroke.getKeyStroke("R"), "rotate right");
    actionMap.put("rotate right", new AbstractAction() {
        public void actionPerformed(ActionEvent e) {

        }
    });

    inputMap.put(KeyStroke.getKeyStroke("PLUS"), "zoom in");
    inputMap.put(KeyStroke.getKeyStroke("EQUALS"), "zoom in");
    actionMap.put("zoom in", new AbstractAction() {
        public void actionPerformed(ActionEvent e) {
            double d1 = zoomHelper(OpenSlideView.this, -1);
            double d2 = zoomHelper(otherView, -1);
            zoomHelper2(OpenSlideView.this, d1);
            zoomHelper2(otherView, d2);
            zoomHelper3(OpenSlideView.this, d1);
            zoomHelper3(otherView, d2);
            repaintHelper(OpenSlideView.this);
            repaintHelper(otherView);
        }
    });

    inputMap.put(KeyStroke.getKeyStroke("MINUS"), "zoom out");
    actionMap.put("zoom out", new AbstractAction() {
        public void actionPerformed(ActionEvent e) {
            double d1 = zoomHelper(OpenSlideView.this, 1);
            double d2 = zoomHelper(otherView, 1);
            zoomHelper2(OpenSlideView.this, d1);
            zoomHelper2(otherView, d2);
            zoomHelper3(OpenSlideView.this, d1);
            zoomHelper3(otherView, d2);
            repaintHelper(OpenSlideView.this);
            repaintHelper(otherView);
        }
    });

    inputMap.put(KeyStroke.getKeyStroke("Z"), "zoom to fit");
    actionMap.put("zoom to fit", new AbstractAction() {
        public void actionPerformed(ActionEvent e) {
            // System.out.println("zoom");
            zoomToFit();
            centerSlidePrivate();
            paintBackingStore();
            repaint();
        }
    });

    inputMap.put(KeyStroke.getKeyStroke("1"), "zoom to 1:1");
    actionMap.put("zoom to 1:1", new AbstractAction() {
        public void actionPerformed(ActionEvent e) {
            // System.out.println("zoom 1:1");
            double d1 = zoomHelper(OpenSlideView.this, Integer.MIN_VALUE);
            double d2 = zoomHelper(otherView, Integer.MIN_VALUE);
            zoomHelper2(OpenSlideView.this, d1);
            zoomHelper2(otherView, d2);
            zoomHelper3(OpenSlideView.this, d1);
            zoomHelper3(otherView, d2);
            repaintHelper(OpenSlideView.this);
            repaintHelper(otherView);
        }
    });

    inputMap.put(KeyStroke.getKeyStroke("BACK_QUOTE"), "toggle pins");
    actionMap.put("toggle pins", new AbstractAction() {
        public void actionPerformed(ActionEvent e) {
            selectionsAsPins = !selectionsAsPins;
            if (otherView != null) {
                otherView.selectionsAsPins = !otherView.selectionsAsPins;
            }
            repaintHelper(OpenSlideView.this);
            repaintHelper(otherView);
        }
    });

    // install as parents
    InputMap oldInputMap = getInputMap();
    ActionMap oldActionMap = getActionMap();
    inputMap.setParent(oldInputMap.getParent());
    oldInputMap.setParent(inputMap);
    actionMap.setParent(oldActionMap.getParent());
    oldActionMap.setParent(actionMap);
}

Answer 1

i want to be able to perform mouse actions on both of them at the same time

没有任何意义。如果某个组件不可见，为什么要这样做呢？也许您需要让您的组件保持其当前状态。因此，当您更改顶部组件的状态时，您会更新隐藏组件的状态。如果隐藏的组件变得可见，它将自动以当前状态绘制。

Plainly put, i want the not-visible JPanel to track down the mouse.

事件仅分派(dispatch)到单个组件。

但是，您可以使用 Component.dispatchEvent(...) 方法将新事件分派(dispatch)到单独的组件。