将事件传递给父母

Question

我想创建一个应用程序,其中一些事件应该被处理,好像它们被传递到父容器一样.例如,我有一个JPanel包含JLabel.顶部JPanel实现了鼠标按压和拖动.我需要做什么,以使事件看起来像他们到达JPanel而不是标签本身.(更改源对象很重要)

有没有比实际实现事件并在父代中复制它们更好的解决方案？(在一些具有> 5个孩子的物体之后,这将变得乏味).

Answer 1

在事件监听器中,您可以将事件分派给父组件.

作为myEvent事件处理函数参数:

Component source=(Component)myEvent.getSource();
source.getParent().dispatchEvent(myEvent);

但是这个解决方案意味着为要添加的每个元素创建一个新的EventListener.

因此,您可以创建单个事件处理程序并重用它,将其添加到所有选定的子项中,如下所示:

final Container parent=this; //we are a the parent container creation code
MouseListener myCommonListener=new MouseListener() {
    @Override
    public void mouseClicked(MouseEvent e) {
        parent.dispatchEvent(e);
    }
    @Override
    public void mouseEntered(MouseEvent e) {
        parent.dispatchEvent(e);
    }
    @Override
    public void mouseExited(MouseEvent e) {
        parent.dispatchEvent(e);
    }
    @Override
    public void mousePressed(MouseEvent e) {
        parent.dispatchEvent(e);
    }
    @Override
    public void mouseReleased(MouseEvent e) {
        parent.dispatchEvent(e);
    }
};

JLabel label=new JLabel("This is the first Label");
label.addMouseListener(myCommonListener);

JLabel label2=new JLabel("This is the second Label");
label2.addMouseListener(myCommonListener);
//... and so on 

Answer 2

您应该在将事件分派给父级之前转换事件。转换包括坐标转换到父相关。

public class RedispatchingMouseAdapter implements MouseListener, MouseWheelListener, MouseMotionListener{

    public void mouseClicked(MouseEvent e) {
        redispatchToParent(e);
    }

    public void mousePressed(MouseEvent e) {
        redispatchToParent(e);
    }

    public void mouseReleased(MouseEvent e) {
        redispatchToParent(e);
    }

    public void mouseEntered(MouseEvent e) {
        redispatchToParent(e);
    }

    public void mouseExited(MouseEvent e) {
        redispatchToParent(e);
    }

    public void mouseWheelMoved(MouseWheelEvent e){
        redispatchToParent(e);
    }

    public void mouseDragged(MouseEvent e){
        redispatchToParent(e);
    }

    public void mouseMoved(MouseEvent e) {
        redispatchToParent(e);
    }

    private void redispatchToParent(MouseEvent e){
        Component source = (Component) e.getSource();
        MouseEvent parentEvent = SwingUtilities.convertMouseEvent(source, e, source.getParent());
        source.getParent().dispatchEvent(parentEvent);
    }
}