java - 当鼠标悬停在 JTable 上时滚动 JPanel

Question

我在 JPanel 内有一个 JTable。我可以使用鼠标滚轮上下滚动 JPanel，但是当我的鼠标悬停在 JTable 上时，我必须将其移出表格才能向后滚动使用滚轮打开 JPanel。如果鼠标悬停在 JTable 上，是否可以使用滚轮上下滚动 JPanel？

Answer 1

我采纳了上面评论中至强的建议，​​并实现了一个鼠标滚轮监听器，它将鼠标滚轮事件转发到父组件。请参阅下面的代码。

public class CustomMouseWheelListener implements MouseWheelListener {

  private JScrollBar bar;
  private int previousValue = 0;
  private JScrollPane parentScrollPane;
  private JScrollPane customScrollPane;

  /** @return The parent scroll pane, or null if there is no parent. */
  private JScrollPane getParentScrollPane() {
    if (this.parentScrollPane == null) {
      Component parent = this.customScrollPane.getParent();
      while (!(parent instanceof JScrollPane) && parent != null) {
        parent = parent.getParent();
      }
      this.parentScrollPane = (JScrollPane) parent;
    }
    return this.parentScrollPane;
  }

  /**
   * Creates a new CustomMouseWheelListener.
   * @param customScrollPane The scroll pane to which this listener belongs.
   */
  public CustomMouseWheelListener(JScrollPane customScrollPane) {
    ValidationUtils.checkNull(customScrollPane);
    this.customScrollPane = customScrollPane;
    this.bar = this.customScrollPane.getVerticalScrollBar();
  }

  /** {@inheritDoc} */
  @Override
  public void mouseWheelMoved(MouseWheelEvent event) {
    JScrollPane parent = getParentScrollPane();
    if (parent != null) {
      if (event.getWheelRotation() < 0) {
        if (this.bar.getValue() == 0 && this.previousValue == 0) {
          parent.dispatchEvent(cloneEvent(event));
        }
      }
      else {
        if (this.bar.getValue() == getMax() && this.previousValue == getMax()) {
          parent.dispatchEvent(cloneEvent(event));
        }
      }
      this.previousValue = this.bar.getValue();
    }
    else {
      this.customScrollPane.removeMouseWheelListener(this);
    }
  }

  /** @return The maximum value of the scrollbar. */
  private int getMax() {
    return this.bar.getMaximum() - this.bar.getVisibleAmount();
  }

  /**
   * Copies the given MouseWheelEvent.
   * 
   * @param event The MouseWheelEvent to copy.
   * @return A copy of the mouse wheel event.
   */
  private MouseWheelEvent cloneEvent(MouseWheelEvent event) {
    return new MouseWheelEvent(getParentScrollPane(), event.getID(), event.getWhen(),
        event.getModifiers(), 1, 1, event.getClickCount(), false, event.getScrollType(),
        event.getScrollAmount(), event.getWheelRotation());
  }

}