예제 #1
0
  /**
   * Adds a widget to the specified edge of the dock. If the widget is already a child of this
   * panel, this method behaves as though {@link #remove(Widget)} had already been called.
   *
   * @param widget the widget to be added
   * @param direction the widget's direction in the dock
   * @param before the widget before which to insert the new child, or <code>null</code> to append
   */
  protected void insert(Widget widget, Direction direction, double size, Widget before) {
    assertIsChild(before);

    // Validation.
    if (before == null) {
      assert center == null : "No widget may be added after the CENTER widget";
    } else {
      assert direction != Direction.CENTER : "A CENTER widget must always be added last";
    }

    // Detach new child.
    widget.removeFromParent();

    // Logical attach.
    WidgetCollection children = getChildren();
    if (before == null) {
      children.add(widget);
    } else {
      int index = children.indexOf(before);
      children.insert(widget, index);
    }

    if (direction == Direction.CENTER) {
      center = widget;
    }

    // Physical attach.
    Layer layer =
        layout.attachChild(
            widget.getElement(), (before != null) ? before.getElement() : null, widget);
    LayoutData data = new LayoutData(direction, size, layer);
    widget.setLayoutData(data);

    // Adopt.
    adopt(widget);

    // Update the layout.
    animate(0);
  }