com.alkacon.geranium.client.ui.FloatDecoratedPanel Maven / Gradle / Ivy
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/*
* This library is part of Geranium -
* an open source UI library for GWT.
*
* Copyright (c) Alkacon Software GmbH (http://www.alkacon.com)-
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* For further information about Alkacon Software, please see the
* company website: http://www.alkacon.com
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
package com.alkacon.geranium.client.ui;
import com.alkacon.geranium.client.ui.css.I_FloatDecoratedPanelCss;
import com.alkacon.geranium.client.ui.css.I_LayoutBundle;
import com.google.gwt.core.client.Scheduler;
import com.google.gwt.dom.client.Style.Float;
import com.google.gwt.dom.client.Style.Unit;
import com.google.gwt.dom.client.Style.Visibility;
import com.google.gwt.user.client.ui.Composite;
import com.google.gwt.user.client.ui.FlowPanel;
import com.google.gwt.user.client.ui.Widget;
/**
* A widget used for laying out multiple widgets horizontally.
*
* It contains two panels, the "primary" (or main) panel and the "float" panel,
* to which widgets can be added. The float panel is styled so as to
* float left of the primary panel, and the primary panel's left margin is
* set to the width of the float panel. If the widget starts out as hidden,
* the float panel width can not be measured, so you have to call the updateLayout
* method manually when the widget becomes visible.
*/
public class FloatDecoratedPanel extends Composite implements I_Truncable {
/** Css resource for this widget. */
static final I_FloatDecoratedPanelCss CSS = I_LayoutBundle.INSTANCE.floatDecoratedPanelCss();
/** The float panel. */
private FlowPanel m_floatBox = new FlowPanel();
/** The panel containing both the main and float panel. */
private FlowPanel m_panel = new FlowPanel();
/** The main panel. */
private FlowPanel m_primary = new FlowPanel();
/**
* Creates a new instance of the widget.
*/
public FloatDecoratedPanel() {
m_panel.setStyleName(CSS.floatDecoratedPanel());
m_floatBox.setStyleName(CSS.floatBox());
m_primary.setStyleName(CSS.primary());
m_panel.add(m_floatBox);
m_panel.add(m_primary);
m_floatBox.getElement().getStyle().setFloat(Float.LEFT);
initWidget(m_panel);
// we only make the widget visible after the layout has been updated to prevent "flickering"
getElement().getStyle().setVisibility(Visibility.HIDDEN);
}
/**
* Adds a widget to the main panel.
*
* @param widget the widget to add
*/
public void add(Widget widget) {
m_primary.add(widget);
}
/**
* Adds a widget to the float panel.
*
* @param widget the widget to add
*/
public void addToFloat(Widget widget) {
m_floatBox.add(widget);
updateLayout();
}
/**
* Adds a widget to the front of the float panel.
*
* @param widget the widget to add
*/
public void addToFrontOfFloat(Widget widget) {
m_floatBox.insert(widget, 0);
}
/**
* Returns the widget at the given position.
*
* @param index the position
*
* @return the widget at the given position
*/
public Widget getWidget(int index) {
return m_primary.getWidget(index);
}
/**
* @see com.alkacon.geranium.client.ui.I_Truncable#truncate(java.lang.String, int)
*/
public void truncate(String textMetricsPrefix, int widgetWidth) {
int width = widgetWidth;
width -= (!isAttached() ? 30 * m_floatBox.getWidgetCount() : getFloatBoxWidth());
for (Widget widget : m_primary) {
if (widget instanceof I_Truncable) {
((I_Truncable)widget).truncate(textMetricsPrefix, width);
}
}
}
/**
* Sets the left margin of the main panel to the width of the float panel.
*/
public void updateLayout() {
// TODO: we should not do this kind of things...
if (!isAttached()) {
return;
}
int floatBoxWidth = getFloatBoxWidth();
m_primary.getElement().getStyle().setMarginLeft(floatBoxWidth, Unit.PX);
updateVerticalMargin();
}
/**
* Automatically calls the updateLayout method after insertion into the DOM.
*
* @see com.google.gwt.user.client.ui.Widget#onLoad()
*/
@Override
protected void onLoad() {
/* defer until children have been (hopefully) layouted. */
Scheduler.get().scheduleDeferred(new Scheduler.ScheduledCommand() {
/**
* @see com.google.gwt.user.client.Command#execute()
*/
public void execute() {
updateLayout();
// layout update has finished, now it's OK to show the widget
getElement().getStyle().setVisibility(Visibility.VISIBLE);
}
});
}
/**
* Returns the width of the float box.
*
* @return a width
*/
private int getFloatBoxWidth() {
return m_floatBox.getOffsetWidth();
}
/**
* Updates the vertical margin of the float box such that its vertical middle point coincides
* with the vertical middle point of the primary panel.
*/
private void updateVerticalMargin() {
int floatHeight = m_floatBox.getOffsetHeight();
int primaryHeight = m_primary.getOffsetHeight();
int verticalOffset = (primaryHeight - floatHeight) / 2;
m_floatBox.getElement().getStyle().setMarginTop(verticalOffset, Unit.PX);
}
}