/*
* Ext GWT - Ext for GWT
* Copyright(c) 2007, 2008, Ext JS, LLC.
* licensing@extjs.com
*
* http://extjs.com/license
*/
package com.extjs.gxt.ui.client.dnd;
import com.extjs.gxt.ui.client.Events;
import com.extjs.gxt.ui.client.event.BaseObservable;
import com.extjs.gxt.ui.client.event.DNDEvent;
import com.extjs.gxt.ui.client.event.DNDListener;
import com.extjs.gxt.ui.client.event.DragEvent;
import com.extjs.gxt.ui.client.event.DragListener;
import com.extjs.gxt.ui.client.fx.Draggable;
import com.extjs.gxt.ui.client.widget.Component;
/**
* Identifies a component that drag and drops can be initiated from.
*
* <p>
* Drag sources must set the data that will be dragged during a drag operation.
* The data can be specified either by using {@link #setData(Object)} or,
* setting the data via the DND event when a drag begins.
* </p>
*
* <p>
* Drag sources are responsible for removing the dragged data from the source
* component after a valid drop. Use {@link DropTarget#getOperation()} to
* determine if the data was copied or moved. The target is accessible via the
* DNDEvent passed to {@link #onDragDrop(DNDEvent)} and listeners.
* </p>
*
* <dl>
* <dt><b>Events:</b></dt>
*
* <dd><b>DragStart</b> : DNDEvent(source, component, event, dragEvent, status)<br>
* <div>Fires after the user begins a drag and drop operation.</div>
* <ul>
* <li>source : this</li>
* <li>component : the source component</li>
* <li>event : the dom event</li>
* <li>dragEvent : the drag event (draggable)</li>
* <li>status : the status object</li>
* </ul>
* </dd>
*
* <dd><b>DragCancel</b> : DNDEvent(source, component, event, dragEvent)<br>
* <div>Fires after a drag is cancelled.</div>
* <ul>
* <li>source : this</li>
* <li>component : the source component</li>
* <li>event : the dom event</li>
* <li>dragEvent : the drag event (draggable)</li>
* </ul>
* </dd>
*
* <dd><b>Drop</b> : DNDEvent(source, component, data, event, dragEvent, status)
* <br>
* <div>Fires after a drop occurs.</div>
* <ul>
* <li>source : this</li>
* <li>component : the source component</li>
* <li>data : the transferred data</li>
* <li>event : the dom event</li>
* <li>dragEvent : the drag event (draggable)</li>
* <li>status : the status object</li>
* </ul>
* </dd>
*
* </dl>
*/
public class DragSource extends BaseObservable {
protected Component component;
protected Draggable draggable;
protected DragListener listener;
protected Object data;
protected StatusProxy statusProxy = StatusProxy.get();
private String statusText;
private String group = "";
/**
* @param component
*/
public DragSource(Component component) {
this.component = component;
listener = new DragListener() {
@Override
public void dragCancel(DragEvent de) {
onDraggableDragCancel(de);
}
@Override
public void dragEnd(DragEvent de) {
onDraggableDragEnd(de);
}
@Override
public void dragMove(DragEvent de) {
onDraggableDragMove(de);
}
@Override
public void dragStart(DragEvent de) {
onDraggableDragStart(de);
}
};
draggable = new Draggable(component);
draggable.setUseProxy(true);
draggable.setSizeProxyToSource(false);
draggable.setMoveAfterProxyDrag(false);
draggable.addDragListener(listener);
}
/**
* Adds a drag and drop listener.
*
* @param listener the listener to add
*/
public void addDNDListener(DNDListener listener) {
addListener(Events.DragStart, listener);
addListener(Events.Drop, listener);
}
/**
* Returns the source component.
*
* @return the component
*/
public Component getComponent() {
return component;
}
/**
* Returns the data to be moved or copied.
*
* @return the data
*/
public Object getData() {
return data;
}
/**
* Returns the draggable instance.
*
* @return the draggable instance
*/
public Draggable getDraggable() {
return draggable;
}
/**
* Returns the source's drag drop group.
*
* @return the group name or null if not specified
*/
public String getGroup() {
return group;
}
/**
* Returns the status text.
*
* @return the text
*/
public String getStatusText() {
return statusText;
}
/**
* Removes the drag and drop listener.
*
* @param listener the listener to remove
*/
public void removeDNDListener(DNDListener listener) {
removeListener(Events.DragStart, listener);
removeListener(Events.Drop, listener);
}
/**
* Sets the data for the drag drop operation.
*
* @param data the data
*/
public void setData(Object data) {
this.data = data;
}
/**
* Sets the drag drop group. If specified, drops will only be allowed on drop
* targets with the same group value.
*
* @param group the group name
*/
public void setGroup(String group) {
this.group = group;
}
/**
* Sets the text to be used on the status proxy object. If the drag source
* supports selection, {0} will be substituted with the selection size.
*
* @param statusText the status text
*/
public void setStatusText(String statusText) {
this.statusText = statusText;
}
protected void onDragDrop(DNDEvent event) {
}
/**
* Called when a drag operation begins on the target component. Subclasses or
* any listeners must set the event.doit field to true to allow the drag
* operation.
*
* @param event the dnd event
*/
protected void onDragStart(DNDEvent event) {
}
/**
* Called when a drag operation has been cancelled.
*
* @param event the dnd event
*/
protected void onDragCancelled(DNDEvent event) {
}
private void onDraggableDragCancel(DragEvent de) {
DNDEvent e = new DNDEvent(this);
e.event = de.event;
e.dragEvent = de;
e.component = component;
e.source = this;
DNDManager.get().handleDragCancelled(this, e);
}
private void onDraggableDragEnd(DragEvent de) {
DNDEvent e = new DNDEvent(this);
e.data = data;
e.event = de.event;
e.dragEvent = de;
e.component = component;
e.status = statusProxy;
e.source = this;
if (e.data != null) {
DNDManager.get().handleDragEnd(this, e);
}
}
private void onDraggableDragMove(DragEvent de) {
de.x = de.getClientX() + 12;
de.y = de.getClientY() + 12;
DNDEvent e = new DNDEvent(this);
e.event = de.event;
e.dragEvent = de;
e.component = component;
e.data = data;
e.status = statusProxy;
e.source = this;
DNDManager.get().handleDragMove(this, e);
}
private void onDraggableDragStart(DragEvent de) {
DNDEvent e = new DNDEvent(this);
e.data = data;
e.event = de.event;
e.dragEvent = de;
e.component = component;
e.status = statusProxy;
e.source = this;
DNDManager.get().handleDragStart(this, e);
// instruct draggable
de.doit = e.doit;
}
}