Viewport.java

/*
 Copyright (c) 2014 Ahomé Innovation Technologies. All rights reserved.

 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.ait.toolkit.sencha.ext.client.ui;

import java.util.ArrayList;
import java.util.List;

import com.ait.toolkit.sencha.ext.client.core.Component;
import com.ait.toolkit.sencha.ext.client.core.config.XType;
import com.ait.toolkit.sencha.ext.client.layout.ContainerLayout;
import com.ait.toolkit.sencha.ext.client.layout.Layout;
import com.google.gwt.core.client.JavaScriptObject;
import com.google.gwt.user.client.ui.AcceptsOneWidget;
import com.google.gwt.user.client.ui.IsWidget;
import com.google.gwt.user.client.ui.Widget;

/**
 * A specialized container representing the viewable application area (the browser viewport).
 * 
 * <p>
 * The Viewport renders itself to the document body, and automatically sizes itself to the size of the browser viewport and manages window resizing. There may only be one Viewport
 * created in a page.
 * <p>
 * Like any Container, a Viewport will only perform sizing and positioning on its child Components if you configure it with a layout.
 * <p>
 * A Common layout used with Viewports is border layout, but if the required layout is simpler, a different layout should be chosen.
 * <p>
 * For example, to simply make a single child item occupy all available space, use fit layout.
 * <p>
 * To display one "active" item at full size from a choice of several child items, use card layout.
 * <p>
 * Inner layouts are available because all Panels added to the Viewport, either through its items, or the add method of any of its child Panels may themselves have a layout.
 * <p>
 * The Viewport does not provide scrolling, so child Panels within the Viewport should provide for scrolling if needed using the autoScroll config.
 * 
 * <p>
 * * Adding a AcceptsOneWidget interface with an empty setWidget overriden method to fake the operation and allow for a pure GWT Activty And Place implementation.
 * 
 * 
 * You must not add the "viewport" panel to GWT's RootPanel via RootPanel.get().add(..) - this is done automatically for you.
 */

public class Viewport extends Container implements AcceptsOneWidget {

	private JavaScriptObject jsObj;
	private static Viewport viewPort;
	private Component widget;
	private List<Component> items = new ArrayList<Component>();

	/**
	 * Get the viewport with the given layout
	 * 
	 * @param layout
	 *            , the layout the vieport should use
	 * @return, the singleton instance of the viewport
	 */
	public static Viewport get(Layout layout) {
		return get(layout, 0);
	}

	private static Viewport get(Layout layout, int bodyPadding) {
		if (viewPort == null) {
			viewPort = initViewPort(layout.getValue(), bodyPadding);
		}
		return viewPort;
	}

	public static Viewport get(String layout) {
		if (viewPort == null) {
			viewPort = initViewPort(layout, 0);
		}
		return viewPort;
	}

	/**
	 * Get the viewport with the given layout
	 * 
	 * @param layout
	 *            , the layout the vieport should use
	 * @return, the singleton instance of the viewport
	 */
	public static Viewport get(ContainerLayout layout) {
		return get(layout, 0);
	}

	private static Viewport get(ContainerLayout layout, int bodyPadding) {
		if (viewPort == null) {
			viewPort = initViewPort(layout.getJsObj(), bodyPadding);
		}
		return viewPort;
	}

	/**
	 * Get the viewport with the default layout
	 * 
	 * @return, the singleton instance of the viewport
	 */
	public static Viewport get() {
		if (viewPort == null) {
			viewPort = initViewPort(Layout.AUTO.getValue(), 0);
		}
		return viewPort;
	}

	private Viewport() {

	}

	public static Viewport cast(Component component) {
		return new Viewport(component.getOrCreateJsObj());
	}

	protected Viewport(JavaScriptObject obj) {
		super(obj);
	}

	public String getXType() {
		return XType.VIEWPORT.getValue();
	}

	protected native JavaScriptObject create(JavaScriptObject config) /*-{
		return new $wnd.Ext.container.Viewport(config);
	}-*/;

	public void setWidget(final Widget w) {
		// Validate
		if (w == widget || w == null) {
			return;
		}

		if (w != null) {
			if (widget != null) {
				widget.hide();
			}

			if (items.indexOf((Component) w) < 0) {
				items.add((Component) w);
				// Physical attach.
				add(w);
			}
			((Component) w).show();
			// setActiveItem((Container) w);
			// Logical add
			widget = (Component) w;
		}

	}

	@Override
	public void setWidget(IsWidget w) {
		setWidget(asWidgetOrNull(w));
	}

	public native void attach() /*-{
		@com.ait.toolkit.sencha.ext.client.ui.Viewport::viewPort.@com.google.gwt.user.client.ui.Widget::onAttach()();
	}-*/;

	/**
	 * Calling layout on the viewport has no effect. You must specify the initial layout while calling <br/>
	 * <code>
	 * Viewport.get(Layout layout)
	 * </code>
	 */
	@Override
	public void setLayout(ContainerLayout layout) throws IllegalStateException {

	}

	private native static Viewport initViewPort(String l, int padding) /*-{
		var viewport = new $wnd.Ext.container.Viewport({
			layout : l,
			bodyPadding : padding
		});
		var container = @com.ait.toolkit.sencha.ext.client.ui.Viewport::new(Lcom/google/gwt/core/client/JavaScriptObject;)(viewport);
		return container;
	}-*/;

	private native static Viewport initViewPort(JavaScriptObject l, int padding) /*-{
		var viewport = new $wnd.Ext.container.Viewport({
			layout : l,
			bodyPadding : padding
		});
		var container = @com.ait.toolkit.sencha.ext.client.ui.Viewport::new(Lcom/google/gwt/core/client/JavaScriptObject;)(viewport);
		return container;
	}-*/;

}