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This component defines a subtree of the component tree as draggable for drag-and-drop operations. Within such a "drag zone," you can click the mouse button on an item and drag it to any component that supports drop operations (a "drop zone"). It encodes all the necessary JavaScript for supporting drag-and-drop operations.
Encodes all necessary JavaScript to perform drag actions
Can be used within any component type that provides the required properties for drag operations
Supports drag-and-drop between different forms
Table 6.135. rich : dragSupport attributes
| Attribute Name |
Description
|
|---|---|
| action | MethodBinding pointing at the application action to be invoked, if this UIComponent is activated by you, during the Apply Request Values or Invoke Application phase of the request processing lifecycle, depending on the value of the immediate property |
| actionListener | MethodBinding pointing at method accepting an ActionEvent with return type void |
| binding | JSF: The attribute takes a value-binding expression for a component property of a backing bean |
| disableDefault | Disable default action for target event (append "return false;" to JavaScript) |
| dragIndicator | Id of a component that is used as drag pointer during the drag operation |
| dragListener | MethodBinding representing an action listener method that will be notified after drag operation |
| dragType | A drag zone type that is used for zone definition, which elements can be accepted by a drop zone |
| dragValue | Data to be sent to a drop zone after a drop event |
| eventsQueue | Name of requests queue to avoid send next request before complete other from same event. Can be used to reduce number of requests of frequently events (key press, mouse move etc.) |
| focus | ID of an element to set focus after request is completed on client side |
| grabbingCursors | list of comma separated cursors that indicates then the you has grabbed something |
| grabCursors | List of comma separated cursors that indicates then you can grab and drag an object |
| id | JSF: Every component may have a unique id that is automatically created if omitted |
| ignoreDupResponses | Attribute allows to ignore an Ajax Response produced by a request if the newest 'similar' request is in a queue already. ignoreDupResponses="true" does not cancel the request while it is processed on the server, but just allows to avoid unnecessary updates on the client side if the response isn't actual now |
| immediate | True means, that the default ActionListener should be executed immediately (i.e. during Apply Request Values phase of the request processing lifecycle), rather than waiting until the Invoke Application phase |
| limitToList | If "true", then of all AJAX-rendered on the page components only those will be updated, which ID's are passed to the "reRender" attribute of the describable component. "false"-the default value-means that all components with ajaxRendered="true" will be updated. |
| onbeforedomupdate | The client-side script method to be called before DOM is updated |
| oncomplete | The client-side script method to be called after the request is completed |
| ondragend | The client-side script method to be called when the dragging operation is finished |
| ondragstart | The client-side script method to be called when the dragging operation is started |
| ondropout | The client-side script method to be called when the draggable object is moved away from the drop zone |
| ondropover | The client-side script method to be called when the draggable object is over the drop zone |
| rendered | JSF: If "false", this component is not rendered |
| requestDelay | Attribute defines the time (in ms.) that the request will be wait in the queue before it is ready to send. When the delay time is over, the request will be sent to the server or removed if the newest 'similar' request is in a queue already |
| reRender | Id['s] (in format of call UIComponent.findComponent()) of components, rendered in case of AjaxRequest caused by this component. Can be single id, comma-separated list of Id's, or EL Expression with array or Collection |
| similarityGroupingId | If there are any component requests with identical IDs then these requests will be grouped. |
| status | ID (in format of call UIComponent.findComponent()) of Request status component |
| timeout | Response waiting time on a particular request. If a response is not received during this time, the request is aborted |
| value | JSF: The current value for this component |
Table 6.136. Component identification parameters
| Name | Value |
|---|---|
| component-type | org.richfaces.DragSupport |
| component-class | org.richfaces.component.html.HtmlDragSupport |
| component-family | org.richfaces.DragSupport |
| renderer-type | org.richfaces.DragSupportRenderer |
| tag-class | org.richfaces.taglib.DragSupportTag |
Here is a simple example as it could be used on a page:
Example:
...
<h:panelGrid id="drag1">
<rich:dragSupport dragType="item"/>
<!--Some content to be dragged-->
</h:panelGrid>
...
Example:
import org.richfaces.component.html.HtmlDragSupport;
...
HtmlDragSupport myDragZone = new HtmlDragSupport();
...
The dragSupport tag inside a component completely specifies the events and JavaScript required to use the component and it's children for dragging as part of a drag-and-drop operation. In order to work, though, dragSupport must be placed inside a wrapper component that outputs child components and that has the right events defined on it. Thus, this example won't work, because the <h:column> tag doesn't provide the necessary properties for redefining events on the client:
Example:
...
<h:column>
<rich:dragSupport dragIndicator=":form:iii" dragType="text">
<a4j:actionparam value="#{caps.name}" name="name"/>
</rich:dragSupport>
<h:outputText value="#{caps.name}"/>
</h:column>
...
However, using a4j:outputPanel as a wrapper inside <h:column> , the following code could be used successfully:
Example:
...
<h:column>
<a4j:outputPanel>
<rich:dragSupport dragIndicator=":form:iii" dragType="text">
<a4j:actionparam value="#{caps.name}" name="name"/>
</rich:dragSupport>
<h:outputText value="#{caps.name}"/>
</a4j:outputPanel>
</h:column>
...
This code makes all rows of this column draggable.
One of the main attributes for dragSupport is "dragType" , which associates a name with the drag zone. Only drop zones with this name as an acceptable type can be used in drag-and-drop operations. Here is an example:
Example:
...
<h:panelGrid id="drag1">
<rich:dragSupport dragType="singleItems" .../>
<!--Some content to be dragged-->
</h:panelGrid>
...
<h:panelGrid id="drag2">
<rich:dragSupport dragType="groups" .../>
<!--Some content to be dragged-->
</h:panelGrid>
...
<h:panelGrid id="drop1">
<rich:dropSupport acceptedTypes="singleItems" .../>
<!--Drop zone content-->
</h:panelGrid>
...
In this example, the
drop1
panel grid is a drop zone that invokes drag-and-drop for
drops of items from the first
drag1
panel grid, but not the second
drag2
panel grid. In the section about
dropSupport
, you will find an example that shows more detailed
information about moving data between tables with drag and
drop.
The dragSupport component also has a "value" attribute for passing data into the processing after a drop event.
One more important attribute for <rich:dragSupport> is the "dragIndicator" attribute that point to the component id of the <rich:dragIndicator> component to be used for dragged items from this drag zone. If it isn't defined, a default indicator for drag operations is used.
Finally, the component has the following extra attributes for event processing on the client:
"ondragstart"
"ondragend"
You can use your own custom JavaScript functions to handle these events.
If you define width for a outputPanel, in Internet Explorer 6 you can perform a drag and drop operation, placing the mouse cursor on the text in the outputPanel only.
<rich:dragSupport> has no skin parameters and custom style classes , as the component isn't visual.
On the component Live Demo page you can see the example of <rich:dragSupport> usage and sources for the given example.
