java - 给定一个 Swing 容器和坐标，我如何找到制造的鼠标事件的源？

Question

我有一个容器，例如 JFrame 或 JComponent。该容器可能包含诸如按钮、面板等可能具有鼠标监听器的组件。我想做的是创建一个 MouseEvent 并将其添加到系统事件队列中，即模拟用户在某个位置单击容器时发生的情况。我知道点击相对于容器的坐标，但我不知道容器的子代和孙代等是如何排列的。

到目前为止我所拥有的内容如下

    Component source = ????? ;
    final MouseEvent ev = new MouseEvent(source, id, now, modifiers, x, y,
                        xAbs, yAbs, clickCount, popupTrigger, button) ;
    SwingUtilities.invokeAndWait(new Runnable() {
        @Override public void run() {
            EventQueue q = Toolkit.getDefaultToolkit().getSystemEventQueue() ;
            q.postEvent(ev);
        } });

如果我能找到正确的子组件作为源，这就有效。但我怎样才能做到这一点呢？

在java.awt.Container中有一个名为getMouseEventTarget的方法，不幸的是它不是公开的。

我知道我可以使用 java.awt.Robot 执行类似的操作，但我不想实际移动鼠标指针。我希望能够在 headless 模式下执行此操作，我认为 Robot 不太可能工作。

<小时/>

编辑

这是我尝试的解决方案。它基于非公共(public)方法 java.awt.Container.getMouseEventTarget。我想找到一个更简单、更正确的解决方案。

static Triple<Component,Integer,Integer> searchForMouseEventSource( Component p, int x, int y ) {
    synchronized( p.getTreeLock() ) {
        return searchForMouseEventSourceImpl( p, x, y ) ;
    }
}
static private Triple<Component,Integer,Integer> searchForMouseEventSourceImpl( Component comp, int x, int y ) {
    // Based on getMouseEventTarget in java.awt.container
    // Search for a descendant component that can take the event.
    if( comp instanceof Container ) {
        Container cont = (Container) comp ;
        for (int i = 0; i < cont.getComponentCount(); i++) {
            Component child = cont.getComponent(i) ;
            if( child != null && child.isVisible() ) {
                int childX = child.getX() ;
                int childY = child.getY();
                if( child.contains(x - childX, y - childY) ) {
                    Triple<Component,Integer,Integer> result
                        = searchForMouseEventSourceImpl( child, x-childX, y-childY );
                    if( result != null ) return result ;
                }
            }
        }
    }
    // If we get here there, is no descendant that can take the event.
    if( comp.contains(x,y) && takesMouseEvents( comp ) ) {
        return new Triple<Component,Integer,Integer>( comp, x, y) ; }
    else {
        return null ; }
}

static boolean takesMouseEvents( Component comp ) {
    // The following is what we want (from java.awt.Container)
    //return (comp.eventMask & AWTEvent.MOUSE_MOTION_EVENT_MASK) != 0
    //        || (comp.eventMask & AWTEvent.MOUSE_EVENT_MASK) != 0
    //        || (comp.eventMask & AWTEvent.MOUSE_WHEEL_EVENT_MASK) != 0
    //        || comp.mouseListener != null
    //        || comp.mouseMotionListener != null
    //        || comp.mouseWheelListener != null;
    // The next line covers the last 3 cases, I think.
    return comp.getMouseListeners().length != 0 
        || comp.getMouseMotionListeners().length != 0
        || comp.getMouseWheelListeners().length != 0 ;
}

static class Triple<T,U,V> {
    public T first ; 
    public U second ;
    public V third ;
    public Triple( T first, U second, V third ) {
        this.first = first ; this.second = second ; this.third = third ; }
}

Answer 1

This works if I can find the right subcomponent to be the source. But how can I do that?

Component child = container.getComponentAt( Point );

编辑:

这可能会满足您的要求:

Component child = SwingUtilities.getDeepestComponentAt(parent, x, y)