Java tutorial
/* * This library is part of OpenCms - * the Open Source Content Management System * * 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 * * For further information about OpenCms, please see the * project website: http://www.opencms.org * * 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 org.opencms.gwt.client.ui; import org.opencms.gwt.client.Messages; import org.opencms.gwt.client.dnd.CmsDNDHandler; import org.opencms.gwt.client.dnd.I_CmsDragHandle; import org.opencms.gwt.client.dnd.I_CmsDraggable; import org.opencms.gwt.client.dnd.I_CmsDropTarget; import org.opencms.gwt.client.ui.I_CmsButton.ButtonStyle; import org.opencms.gwt.client.ui.css.I_CmsImageBundle; import org.opencms.gwt.client.ui.css.I_CmsLayoutBundle; import org.opencms.gwt.client.ui.css.I_CmsLayoutBundle.I_CmsListItemCss; import org.opencms.gwt.client.ui.input.CmsCheckBox; import org.opencms.gwt.client.util.CmsDomUtil; import java.util.Collections; import java.util.HashSet; import java.util.Iterator; import java.util.LinkedList; import java.util.List; import java.util.Set; import com.google.gwt.core.client.GWT; import com.google.gwt.dom.client.Element; import com.google.gwt.dom.client.Style; import com.google.gwt.dom.client.Style.Position; import com.google.gwt.dom.client.Style.Unit; import com.google.gwt.dom.client.Style.Visibility; import com.google.gwt.uibinder.client.UiBinder; import com.google.gwt.user.client.DOM; import com.google.gwt.user.client.ui.Composite; import com.google.gwt.user.client.ui.RootPanel; import com.google.gwt.user.client.ui.Widget; /** * List item which uses a float panel for layout.<p> * * @since 8.0.0 */ public class CmsListItem extends Composite implements I_CmsListItem { /** * @see com.google.gwt.uibinder.client.UiBinder */ protected interface I_CmsSimpleListItemUiBinder extends UiBinder<CmsFlowPanel, CmsListItem> { // GWT interface, nothing to do here } /** The move handle. */ protected class MoveHandle extends CmsPushButton implements I_CmsDragHandle { /** The draggable. */ private CmsListItem m_draggable; /** * Constructor.<p> * * @param draggable the draggable */ MoveHandle(CmsListItem draggable) { setImageClass(I_CmsImageBundle.INSTANCE.style().moveIcon()); setButtonStyle(ButtonStyle.TRANSPARENT, null); setTitle(Messages.get().key(Messages.GUI_TOOLBAR_MOVE_TO_0)); m_draggable = draggable; } /** * @see org.opencms.gwt.client.dnd.I_CmsDragHandle#getDraggable() */ public I_CmsDraggable getDraggable() { return m_draggable; } } /** The width of a checkbox. */ private static final int CHECKBOX_WIDTH = 20; /** The CSS bundle used for this widget. */ private static final I_CmsListItemCss CSS = I_CmsLayoutBundle.INSTANCE.listItemCss(); /** The ui-binder instance for this class. */ private static I_CmsSimpleListItemUiBinder uiBinder = GWT.create(I_CmsSimpleListItemUiBinder.class); /** The checkbox of this list item, or null if there is no checkbox. */ protected CmsCheckBox m_checkbox; /** The panel which contains both the decorations (checkbox, etc.) and the main widget. */ protected CmsSimpleDecoratedPanel m_decoratedPanel; /** A list of decoration widgets which is used to initialize {@link CmsListItem#m_decoratedPanel}. */ protected LinkedList<Widget> m_decorationWidgets = new LinkedList<Widget>(); /** The decoration width which should be used to initialize {@link CmsListItem#m_decoratedPanel}. */ protected int m_decorationWidth; /** The logical id, it is not the HTML id. */ protected String m_id; /** The list item widget, if this widget has one. */ protected CmsListItemWidget m_listItemWidget; /** The main widget of the list item. */ protected Widget m_mainWidget; /** This widgets panel. */ protected CmsFlowPanel m_panel; /** The drag'n drop place holder element. */ protected Element m_placeholder; /** The provisional drag parent. */ protected Element m_provisionalParent; /** The drag helper. */ private Element m_helper; /** The move handle. */ private MoveHandle m_moveHandle; /** The list item's set of tags. */ private Set<String> m_tags; /** * Default constructor.<p> */ public CmsListItem() { m_panel = uiBinder.createAndBindUi(this); initWidget(m_panel); } /** * Default constructor.<p> * * @param checkBox the checkbox * @param widget the widget to use */ public CmsListItem(CmsCheckBox checkBox, CmsListItemWidget widget) { this(); initContent(checkBox, widget); } /** * Default constructor.<p> * * @param widget the widget to use */ public CmsListItem(CmsListItemWidget widget) { this(); initContent(widget); } /** * @see org.opencms.gwt.client.ui.I_CmsListItem#add(com.google.gwt.user.client.ui.Widget) */ public void add(Widget w) { throw new UnsupportedOperationException(); } /** * Adds a decoration widget to the list item.<p> * * @param widget the widget * @param width the widget width */ public void addDecorationWidget(Widget widget, int width) { addDecoration(widget, width, false); initContent(); } /** * Adds a tag to the widget.<p> * * @param tag the tag which should be added */ public void addTag(String tag) { if (m_tags == null) { m_tags = new HashSet<String>(); } m_tags.add(tag); } /** * Gets the checkbox of this list item.<p> * * This method will return a checkbox if this list item has one, or null if it doesn't. * * @return a check box or null */ public CmsCheckBox getCheckBox() { return m_checkbox; } /** * Returns the decoration widgets of this list item.<p> * * @return the decoration widgets */ public List<Widget> getDecorationWidgets() { return Collections.unmodifiableList(m_decorationWidgets); } /** * @see org.opencms.gwt.client.dnd.I_CmsDraggable#getDragHelper(I_CmsDropTarget) */ public Element getDragHelper(I_CmsDropTarget target) { if (m_helper == null) { if (m_listItemWidget != null) { m_listItemWidget.setAdditionalInfoVisible(false); Iterator<Widget> buttonIterator = m_listItemWidget.getButtonPanel().iterator(); while (buttonIterator.hasNext()) { Widget button = buttonIterator.next(); if (button != m_moveHandle) { button.getElement().getStyle().setVisibility(Visibility.HIDDEN); } } } m_helper = CmsDomUtil.clone(getElement()); // remove all decorations List<com.google.gwt.dom.client.Element> elems = CmsDomUtil.getElementsByClass( I_CmsLayoutBundle.INSTANCE.floatDecoratedPanelCss().decorationBox(), CmsDomUtil.Tag.div, m_helper); for (com.google.gwt.dom.client.Element elem : elems) { elem.removeFromParent(); } // we append the drag helper to the body to prevent any kind of issues // (ie when the parent is styled with overflow:hidden) // and we put it additionally inside a absolute positioned provisional parent // ON the original parent for the eventual animation when releasing Element parentElement = getElement().getParentElement(); if (parentElement == null) { parentElement = target.getElement(); } int elementTop = getElement().getAbsoluteTop(); int parentTop = parentElement.getAbsoluteTop(); m_provisionalParent = DOM.createElement(parentElement.getTagName()); RootPanel.getBodyElement().appendChild(m_provisionalParent); m_provisionalParent.addClassName(I_CmsLayoutBundle.INSTANCE.generalCss().clearStyles()); m_provisionalParent.getStyle().setWidth(parentElement.getOffsetWidth(), Unit.PX); m_provisionalParent.appendChild(m_helper); Style style = m_helper.getStyle(); style.setWidth(m_helper.getOffsetWidth(), Unit.PX); // the dragging class will set position absolute m_helper.addClassName(I_CmsLayoutBundle.INSTANCE.listItemWidgetCss().dragging()); style.setTop(elementTop - parentTop, Unit.PX); m_provisionalParent.getStyle().setPosition(Position.ABSOLUTE); m_provisionalParent.getStyle().setTop(parentTop, Unit.PX); m_provisionalParent.getStyle().setLeft(parentElement.getAbsoluteLeft(), Unit.PX); m_provisionalParent.getStyle().setZIndex(I_CmsLayoutBundle.INSTANCE.constants().css().zIndexDND()); } // ensure mouse out if (m_listItemWidget != null) { m_listItemWidget.forceMouseOut(); } CmsDomUtil.ensureMouseOut(this); return m_helper; } /** * @see org.opencms.gwt.client.ui.I_CmsListItem#getId() */ public String getId() { return m_id; } /** * Returns the list item widget of this list item, or null if this item doesn't have a list item widget.<p> * * @return a list item widget or null */ public CmsListItemWidget getListItemWidget() { if ((m_mainWidget == null) || !(m_mainWidget instanceof CmsListItemWidget)) { return null; } return (CmsListItemWidget) m_mainWidget; } /** * Returns the parent list.<p> * * @return the parent list */ @SuppressWarnings("unchecked") public CmsList<CmsListItem> getParentList() { Widget parent = getParent(); if (parent == null) { return null; } return (CmsList<CmsListItem>) parent; } /** * @see org.opencms.gwt.client.dnd.I_CmsDraggable#getParentTarget() */ public I_CmsDropTarget getParentTarget() { return getParentList(); } /** * @see org.opencms.gwt.client.dnd.I_CmsDraggable#getPlaceholder(I_CmsDropTarget) */ public Element getPlaceholder(I_CmsDropTarget target) { if (m_placeholder == null) { if (m_listItemWidget != null) { m_listItemWidget.setAdditionalInfoVisible(false); } m_placeholder = cloneForPlaceholder(this); } return m_placeholder; } /** * @see org.opencms.gwt.client.dnd.I_CmsDraggable#hasTag(java.lang.String) */ public boolean hasTag(String tag) { return (m_tags != null) && m_tags.contains(tag); } /** * Initializes the move handle with the given drag and drop handler and adds it to the list item widget.<p> * * This method will not work for list items that don't have a list-item-widget.<p> * * @param dndHandler the drag and drop handler * * @return <code>true</code> if initialization was successful */ public boolean initMoveHandle(CmsDNDHandler dndHandler) { return initMoveHandle(dndHandler, false); } /** * Initializes the move handle with the given drag and drop handler and adds it to the list item widget.<p> * * This method will not work for list items that don't have a list-item-widget.<p> * * @param dndHandler the drag and drop handler * * @param addFirst if true, adds the move handle as first child * * @return <code>true</code> if initialization was successful */ public boolean initMoveHandle(CmsDNDHandler dndHandler, boolean addFirst) { if (m_moveHandle != null) { return true; } if (m_listItemWidget == null) { return false; } m_moveHandle = new MoveHandle(this); if (addFirst) { m_listItemWidget.addButtonToFront(m_moveHandle); } else { m_listItemWidget.addButton(m_moveHandle); } m_moveHandle.addMouseDownHandler(dndHandler); return true; } /** * @see org.opencms.gwt.client.dnd.I_CmsDraggable#onDragCancel() */ public void onDragCancel() { clearDrag(); } /** * @see org.opencms.gwt.client.dnd.I_CmsDraggable#onDrop(org.opencms.gwt.client.dnd.I_CmsDropTarget) */ public void onDrop(I_CmsDropTarget target) { clearDrag(); } /** * @see org.opencms.gwt.client.dnd.I_CmsDraggable#onStartDrag(org.opencms.gwt.client.dnd.I_CmsDropTarget) */ public void onStartDrag(I_CmsDropTarget target) { CmsDomUtil.ensureMouseOut(getMoveHandle().getElement()); setVisible(false); } /** * @see org.opencms.gwt.client.ui.I_CmsListItem#setId(java.lang.String) */ public void setId(String id) { CmsList<CmsListItem> parentList = getParentList(); if (parentList != null) { parentList.changeId(this, id); } m_id = id; } /** * @see org.opencms.gwt.client.ui.I_CmsTruncable#truncate(java.lang.String, int) */ public void truncate(String textMetricsPrefix, int widgetWidth) { for (Widget widget : m_panel) { if (!(widget instanceof I_CmsTruncable)) { continue; } int width = widgetWidth - 4; // just to be on the safe side if (widget instanceof CmsList<?>) { width -= 25; // 25px left margin } ((I_CmsTruncable) widget).truncate(textMetricsPrefix, width); } } /** * Adds a check box to this list item.<p> * * @param checkbox the check box */ protected void addCheckBox(CmsCheckBox checkbox) { assert m_checkbox == null; m_checkbox = checkbox; addDecoration(m_checkbox, CHECKBOX_WIDTH, false); m_checkbox.addStyleName(CSS.listItemCheckbox()); } /** * Helper method for adding a decoration widget and updating the decoration width accordingly.<p> * * @param widget the decoration widget to add * @param width the intended width of the decoration widget * @param first if true, inserts the widget at the front of the decorations, else at the end. */ protected void addDecoration(Widget widget, int width, boolean first) { m_decorationWidgets.add(widget); m_decorationWidth += width; } /** * Adds the main widget to the list item.<p> * * In most cases, the widget will be a list item widget. If this is the case, then further calls to {@link CmsListItem#getListItemWidget()} will * return the widget which was passed as a parameter to this method. Otherwise, the method will return null.<p> * * @param widget */ protected void addMainWidget(Widget widget) { assert m_mainWidget == null; assert m_listItemWidget == null; if (widget instanceof CmsListItemWidget) { m_listItemWidget = (CmsListItemWidget) widget; } m_mainWidget = widget; } /** * Clones the given item to be used as a place holder.<p> * * @param listItem the item to clone * * @return the cloned item */ protected Element cloneForPlaceholder(CmsListItem listItem) { Element clone = CmsDomUtil.clone(listItem.getElement()); clone.addClassName(I_CmsLayoutBundle.INSTANCE.dragdropCss().dragPlaceholder()); // remove hoverbar List<Element> elems = CmsDomUtil.getElementsByClass( I_CmsLayoutBundle.INSTANCE.listItemWidgetCss().buttonPanel(), CmsDomUtil.Tag.div, clone); for (com.google.gwt.dom.client.Element elem : elems) { elem.removeFromParent(); } return clone; } /** * Returns the move handle.<p> * * @return the move handle */ protected I_CmsDragHandle getMoveHandle() { return m_moveHandle; } /** * This internal helper method creates the actual contents of the widget by combining the decorators and the main widget.<p> */ protected void initContent() { if (m_decoratedPanel != null) { m_decoratedPanel.removeFromParent(); } m_decoratedPanel = new CmsSimpleDecoratedPanel(m_decorationWidth, m_mainWidget, m_decorationWidgets); m_panel.insert(m_decoratedPanel, 0); } /** * This method is a convenience method which sets the checkbox and main widget of this widget, and then calls {@link CmsListItem#initContent()}.<p> * * @param checkbox the checkbox to add * @param mainWidget the mainWidget to add */ protected void initContent(CmsCheckBox checkbox, Widget mainWidget) { addCheckBox(checkbox); addMainWidget(mainWidget); initContent(); } /** * This method is a convenience method which sets the main widget of this widget, and then calls {@link CmsListItem#initContent()}.<p> * * @param mainWidget the main widget to add */ protected void initContent(Widget mainWidget) { addMainWidget(mainWidget); initContent(); } /** * Called when a drag operation for this widget is stopped.<p> */ private void clearDrag() { if (m_listItemWidget != null) { Iterator<Widget> buttonIterator = m_listItemWidget.getButtonPanel().iterator(); while (buttonIterator.hasNext()) { Widget button = buttonIterator.next(); button.getElement().getStyle().clearVisibility(); } } if (m_helper != null) { m_helper.removeFromParent(); m_helper = null; } if (m_provisionalParent != null) { m_provisionalParent.removeFromParent(); m_provisionalParent = null; } setVisible(true); } }