EscKeyDownHandler.java 文件源码

@Override
public void onKeyDown(KeyDownEvent keyDownEvent) {

    if (keyDownEvent.getNativeKeyCode() == KeyCodes.KEY_ESCAPE) {

        SimplePanel panel = WidgetUtil.findWidget(WidgetUtil.getFocusedElement(), SimplePanel.class);

        if (panel != null) {
            WidgetUtil.focus(panel.getParent().getElement());

            // prevent further bubbling of the event as it has only
            // navigational purpose if thrown at this depth. A subsequent
            // press of ESC is not stopped, so ESC abort actions of the
            // application should work as soon as the focus is in
            // "navigational mode" on a grid-cell
            keyDownEvent.preventDefault();
            keyDownEvent.stopPropagation();
        }
    }
}