Java tutorial
/** * Sencha GXT 4.0.0 - Sencha for GWT * Copyright (c) 2006-2015, Sencha Inc. * * licensing@sencha.com * http://www.sencha.com/products/gxt/license/ * * ================================================================================ * Open Source License * ================================================================================ * This version of Sencha GXT is licensed under the terms of the Open Source GPL v3 * license. You may use this license only if you are prepared to distribute and * share the source code of your application under the GPL v3 license: * http://www.gnu.org/licenses/gpl.html * * If you are NOT prepared to distribute and share the source code of your * application under the GPL v3 license, other commercial and oem licenses * are available for an alternate download of Sencha GXT. * * Please see the Sencha GXT Licensing page at: * http://www.sencha.com/products/gxt/license/ * * For clarification or additional options, please contact: * licensing@sencha.com * ================================================================================ * * * ================================================================================ * Disclaimer * ================================================================================ * THIS SOFTWARE IS DISTRIBUTED "AS-IS" WITHOUT ANY WARRANTIES, CONDITIONS AND * REPRESENTATIONS WHETHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION THE * IMPLIED WARRANTIES AND CONDITIONS OF MERCHANTABILITY, MERCHANTABLE QUALITY, * FITNESS FOR A PARTICULAR PURPOSE, DURABILITY, NON-INFRINGEMENT, PERFORMANCE AND * THOSE ARISING BY STATUTE OR FROM CUSTOM OR USAGE OF TRADE OR COURSE OF DEALING. * ================================================================================ */ package com.sencha.gxt.dnd.core.client; import java.util.List; import com.google.gwt.core.client.GWT; import com.google.gwt.dom.client.Element; import com.google.gwt.dom.client.EventTarget; import com.google.gwt.resources.client.ClientBundle; import com.google.gwt.resources.client.ImageResource; import com.google.gwt.user.client.Timer; import com.sencha.gxt.core.client.GXT; import com.sencha.gxt.core.client.dom.AutoScrollSupport; import com.sencha.gxt.core.client.dom.ScrollSupport; import com.sencha.gxt.core.client.dom.XDOM; import com.sencha.gxt.core.client.dom.XElement; import com.sencha.gxt.core.client.util.Point; import com.sencha.gxt.core.client.util.Rectangle; import com.sencha.gxt.data.shared.TreeStore; import com.sencha.gxt.data.shared.event.StoreRemoveEvent; import com.sencha.gxt.data.shared.event.StoreRemoveEvent.StoreRemoveHandler; import com.sencha.gxt.dnd.core.client.DND.Feedback; import com.sencha.gxt.dnd.core.client.DND.Operation; import com.sencha.gxt.widget.core.client.event.XEvent; import com.sencha.gxt.widget.core.client.tree.Tree; import com.sencha.gxt.widget.core.client.tree.Tree.TreeNode; import com.sencha.gxt.widget.core.client.treegrid.TreeGrid; /** * Enables a {@link Tree} to act as the target of a drag and drop operation. * <p/> * Use {@link #setFeedback(com.sencha.gxt.dnd.core.client.DND.Feedback)} to specify whether to allow inserting * items between items, appending items to the end, or both (defaults to * {@link Feedback#BOTH}). * <p/> * Use {@link #setOperation(com.sencha.gxt.dnd.core.client.DND.Operation)} to specify whether to move items or copy * them (defaults to {@link Operation#MOVE}). * * @param <M> the model type */ public class TreeDropTarget<M> extends DropTarget { /** * The tree drop target resources. */ public interface TreeDropTargetResources extends ClientBundle { /** * Returns an icon to indicate an insert at the current item. * * @return an icon to indicate an insert at the current item */ ImageResource dropInsert(); /** * Returns an icon to indicate an insert above the current item. * * @return an icon to indicate an insert above the current item */ ImageResource dropInsertAbove(); /** * Returns an icon to indicate an insert below the current item. * * @return an icon to indicate an insert below the current item */ ImageResource dropInsertBelow(); } protected TreeNode<M> activeItem, appendItem; protected int status; protected TreeDropTargetResources resources = GWT.create(TreeDropTargetResources.class); private boolean allowDropOnLeaf = false; private boolean autoExpand = true, autoScroll = true; private int autoExpandDelay = 800; private boolean restoreTrackMouse; private boolean addChildren; private AutoScrollSupport scrollSupport; /** * Creates a drop target for the specified tree. * * @param tree the tree to enable as a drop target */ public TreeDropTarget(Tree<M, ?> tree) { super(tree); } @SuppressWarnings("unchecked") @Override public Tree<M, ?> getWidget() { return (Tree<M, ?>) super.getWidget(); } /** * Returns true if children are being added when inserting into the TreeStore. * * @return the add children state */ public boolean isAddChildren() { return addChildren; } /** * Returns whether drops are allowed on leaf nodes. * * @return true of drops on leafs are allowed */ public boolean isAllowDropOnLeaf() { return allowDropOnLeaf; } /** * Returns true if auto expand is enabled (defaults to true). * * @return the auto expand state */ public boolean isAutoExpand() { return autoExpand; } /** * Returns true if auto scroll is enabled (defaults to true). * * @return true if auto scroll enabled */ public boolean isAutoScroll() { return autoScroll; } /** * True to add children when inserting models into the TreeStore (defaults to * false). * * @param addChildren true to add children */ public void setAddChildren(boolean addChildren) { this.addChildren = addChildren; } /** * True to allow drops on leaf nodes (defaults to false). * * @param allowDropOnLeaf true to enable drops on leaf nodes */ public void setAllowDropOnLeaf(boolean allowDropOnLeaf) { this.allowDropOnLeaf = allowDropOnLeaf; } /** * True to automatically expand the active tree item when the user hovers over * a collapsed item (defaults to true). Use {@link #setAutoExpandDelay(int)} * to set the delay. * * @param autoExpand true to auto expand */ public void setAutoExpand(boolean autoExpand) { this.autoExpand = autoExpand; } /** * Sets the delay used to auto expand items (defaults to 800). * * @param autoExpandDelay the delay in milliseconds */ public void setAutoExpandDelay(int autoExpandDelay) { this.autoExpandDelay = autoExpandDelay; } /** * True to automatically scroll the tree when the user hovers over the top and * bottom of the tree grid (defaults to true). * * @see ScrollSupport * * @param autoScroll true to enable auto scroll */ public void setAutoScroll(boolean autoScroll) { this.autoScroll = autoScroll; } protected void appendModel(M p, List<?> items, int index) { if (items.size() == 0) return; if (items.get(0) instanceof TreeStore.TreeNode) { @SuppressWarnings("unchecked") List<TreeStore.TreeNode<M>> nodes = (List<TreeStore.TreeNode<M>>) items; if (p == null) { getWidget().getStore().addSubTree(index, nodes); } else { getWidget().getStore().addSubTree(p, index, nodes); } } else { @SuppressWarnings("unchecked") List<M> models = (List<M>) items; if (p == null) { getWidget().getStore().insert(index, models); } else { getWidget().getStore().insert(p, index, models); } } } protected void bind(TreeGrid<M> tree) { // tree.addListener(Events.Unregister, new Listener<TreeGridEvent>() { // public void handleEvent(TreeGridEvent be) { // if (activeItem == be.getTreeNode()) { // activeItem = null; // } // } // }); tree.getTreeStore().addStoreRemoveHandler(new StoreRemoveHandler<M>() { @Override public void onRemove(StoreRemoveEvent<M> event) { if (activeItem.getModel() == event.getItem()) { activeItem = null; } } }); } protected void clearStyle(TreeNode<M> node) { getWidget().getView().onDropChange(node, false); Insert.get().hide(); } protected void handleAppend(DndDragMoveEvent event, final TreeNode<M> item) { // clear any active append item if (activeItem != null && activeItem != item) { clearStyle(activeItem); } status = -1; Insert.get().hide(); event.getStatusProxy().setStatus(true); if (activeItem != null) { clearStyle(activeItem); } if (item != null && item != appendItem && autoExpand && !item.isExpanded()) { Timer t = new Timer() { @Override public void run() { if (item == appendItem) { getWidget().setExpanded(item.getModel(), true); } } }; t.schedule(autoExpandDelay); } appendItem = item; activeItem = item; if (activeItem != null) { // TODO this might not get the right element getWidget().getView().onDropChange(activeItem, true); } } protected void handleAppendDrop(DndDropEvent event, TreeNode<M> item) { // TODO not M, but TreeStore.TreeNode<M> List<?> models = (List<?>) event.getData(); if (models.size() > 0) { M p = null; if (item != null) { p = item.getModel(); appendModel(p, models, getWidget().getStore().getChildCount(item.getModel())); } else { appendModel(p, models, getWidget().getStore().getRootItems().size()); } } } protected void handleInsert(DndDragMoveEvent event, final TreeNode<M> item) { Element e = getWidget().getView().getElementContainer(item); int height = e.getOffsetHeight(); int mid = height / 2; int top = e.getAbsoluteTop(); mid += top; int y = event.getDragMoveEvent().getNativeEvent().<XEvent>cast().getXY().getY(); boolean before = y < mid; boolean leaf = getWidget().isLeaf(item.getModel()); if ((!leaf || allowDropOnLeaf) && (feedback == Feedback.BOTH || feedback == Feedback.APPEND) && ((before && y > top + 4) || (!before && y < top + height - 4))) { handleAppend(event, item); return; } if ((!leaf) && ((before && y > top + 4) || (!before && y < top + height - 4))) { clearStyle(item); return; } // clear any active append item if (activeItem != null && activeItem != item) { clearStyle(activeItem); } appendItem = null; status = before ? 0 : 1; if (activeItem != null) { clearStyle(activeItem); } activeItem = item; if (activeItem != null) { TreeStore<M> store = getWidget().getStore(); int idx = -1; M p = store.getParent(activeItem.getModel()); if (p != null) { idx = store.getChildren(p).indexOf(activeItem.getModel()); } else { idx = store.getRootItems().indexOf(activeItem.getModel()); } ImageResource status = resources.dropInsert(); if (before && idx == 0) { status = resources.dropInsertAbove(); } else if (idx > 1 && !before && p != null && idx == store.getChildCount(p) - 1) { status = resources.dropInsertBelow(); } event.getStatusProxy().setStatus(true, status); if (before) { showInsert(event, e, true); } else { showInsert(event, e, false); } } } protected void handleInsertDrop(DndDropEvent event, TreeNode<M> item, int index) { List<?> droppedItems = (List<?>) event.getData(); if (droppedItems.size() > 0) { int idx = getWidget().getStore().indexOf(item.getModel()); idx = status == 0 ? idx : idx + 1; M p = getWidget().getStore().getParent(item.getModel()); appendModel(p, droppedItems, idx); } } @Override protected void onDragCancelled(DndDragCancelEvent event) { super.onDragCancelled(event); if (autoScroll) { scrollSupport.stop(); } } @Override protected void onDragDrop(DndDropEvent event) { super.onDragDrop(event); if (activeItem != null && status == -1) { clearStyle(activeItem); if (event.getData() != null) { handleAppendDrop(event, activeItem); } } else if (activeItem != null && status != -1) { if (event.getData() != null) { handleInsertDrop(event, activeItem, status); } } else if (activeItem == null && status == -1) { if (event.getData() != null) { handleAppendDrop(event, activeItem); } } else { // event.setCancelled(true); } getWidget().setTrackMouseOver(restoreTrackMouse); status = -1; activeItem = null; appendItem = null; if (autoScroll) { scrollSupport.stop(); } } @Override protected void onDragEnter(DndDragEnterEvent event) { super.onDragEnter(event); event.getStatusProxy().setStatus(false); restoreTrackMouse = getWidget().isTrackMouseOver(); getWidget().setTrackMouseOver(false); if (autoScroll) { if (scrollSupport == null) { scrollSupport = new AutoScrollSupport(getWidget().getElement()); } else if (scrollSupport.getScrollElement() == null) { scrollSupport.setScrollElement(getWidget().getElement()); } scrollSupport.start(); } } @Override protected void onDragFail(DndDropEvent event) { super.onDragFail(event); if (autoScroll) { scrollSupport.stop(); } } @Override protected void onDragLeave(DndDragLeaveEvent event) { super.onDragLeave(event); if (activeItem != null) { clearStyle(activeItem); activeItem = null; } getWidget().setTrackMouseOver(restoreTrackMouse); if (autoScroll) { scrollSupport.stop(); } } @Override protected void onDragMove(DndDragMoveEvent event) { event.setCancelled(false); } @Override protected void showFeedback(DndDragMoveEvent event) { Element target = getElementFromEvent(event.getDragMoveEvent().getNativeEvent()); // TODO this might not get the right element final TreeNode<M> item = getWidget().findNode(Element.as(target)); if (item == null && activeItem != null) { clearStyle(activeItem); } if (item != null && event.getDropTarget().getWidget() == event.getDragSource().getWidget()) { @SuppressWarnings("unchecked") Tree<M, ?> source = (Tree<M, ?>) event.getDragSource().getWidget(); List<M> list = source.getSelectionModel().getSelection(); M overModel = item.getModel(); for (int i = 0; i < list.size(); i++) { M sel = list.get(i); if (overModel == sel) { Insert.get().hide(); event.getStatusProxy().setStatus(false); return; } List<M> children = getWidget().getStore().getAllChildren(sel); if (children.contains(item.getModel())) { Insert.get().hide(); event.getStatusProxy().setStatus(false); return; } } } boolean append = feedback == Feedback.APPEND || feedback == Feedback.BOTH; boolean insert = feedback == Feedback.INSERT || feedback == Feedback.BOTH; if (item == null) { handleAppend(event, item); } else if (insert) { handleInsert(event, item); } else if ((!getWidget().isLeaf(item.getModel()) || allowDropOnLeaf) && append) { handleAppend(event, item); } else { if (activeItem != null) { clearStyle(activeItem); } status = -1; activeItem = null; appendItem = null; Insert.get().hide(); event.getStatusProxy().setStatus(false); } } private void showInsert(DndDragMoveEvent event, Element elem, boolean before) { Insert insert = Insert.get(); insert.show(elem); Rectangle rect = elem.<XElement>cast().getBounds(); int y = before ? rect.getY() - 2 : (rect.getY() + rect.getHeight() - 4); // dont call setBounds though component as it expects widget to be attached insert.getElement().setBounds(rect.getX(), y, rect.getWidth(), 6); } }