/*
* Copyright 2011 Google Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not
* use this file except in compliance with the License. You may obtain a copy of
* the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations under
* the License.
*/
package com.google.gwt.user.client.ui;
import com.google.gwt.dom.client.Style.Unit;
import com.google.gwt.layout.client.Layout;
import com.google.gwt.layout.client.Layout.Layer;
/**
* A simple panel that {@link ProvidesResize} to its one child.
*/
public class SimpleLayoutPanel extends SimplePanel implements RequiresResize,
ProvidesResize {
private Layer layer;
private final Layout layout;
public SimpleLayoutPanel() {
layout = new Layout(getElement());
}
public void onResize() {
if (widget instanceof RequiresResize) {
((RequiresResize) widget).onResize();
}
}
@Override
public boolean remove(Widget w) {
// Validate.
if (widget != w) {
return false;
}
// Orphan.
try {
orphan(w);
} finally {
// Physical detach.
layout.removeChild(layer);
layer = null;
// Logical detach.
widget = null;
}
return true;
}
@Override
public void setWidget(Widget w) {
// Validate
if (w == widget) {
return;
}
// Detach new child.
if (w != null) {
w.removeFromParent();
}
// Remove old child.
if (widget != null) {
remove(widget);
}
// Logical attach.
widget = w;
if (w != null) {
// Physical attach.
layer = layout.attachChild(widget.getElement(), widget);
layer.setTopHeight(0.0, Unit.PX, 100.0, Unit.PCT);
layer.setLeftWidth(0.0, Unit.PX, 100.0, Unit.PCT);
adopt(w);
// Update the layout.
layout.layout();
onResize();
}
}
@Override
protected void onLoad() {
layout.onAttach();
}
@Override
protected void onUnload() {
layout.onDetach();
}
}