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SharpKit Reference

DragDrop Class

Defines the interface and base operation of items that that can be dragged or can be drop targets. It was designed to be extended, overriding the event handlers for startDrag, onDrag, onDragOver and onDragOut. Up to three html elements can be associated with a DragDrop instance:

  • linked element: the element that is passed into the constructor. This is the element which defines the boundaries for interaction with other DragDrop objects.

  • handle element(s): The drag operation only occurs if the element that was clicked matches a handle element. By default this is the linked element, but there are times that you will want only a portion of the linked element to initiate the drag operation, and the setHandleElId() method provides a way to define this.

  • drag element: this represents the element that would be moved along with the cursor during a drag operation. By default, this is the linked element itself as in Ext.dd.DD. setDragElId() lets you define a separate element that would be moved, as in Ext.dd.DDProxy.

This class should not be instantiated until the onload event to ensure that the associated elements are available. The following would define a DragDrop obj that would interact with any other DragDrop obj in the "group1" group:

  
dd = new Ext.dd.DragDrop("div1", "group1");
            

Since none of the event handlers have been implemented, nothing would actually happen if you were to run the code above. Normally you would override this class or one of the default implementations, but you can also override the methods you want on an instance of the class...

  
dd.onDragDrop = function(e, id) {
            alert("dd was dropped on " + id);
            }
            

Namespace: Ext.dd

Base Types

Derived Types

Methods

Name Description
addInvalidHandleClass(JsString) Lets you specify a css class of elements that will not initiate a drag
addInvalidHandleId(JsString) Lets you to specify an element id for a child of a drag handle that should not initiate a drag
addInvalidHandleType(JsString) Allows you to specify a tag name that should not start a drag operation when clicked. This is designed to facilitate embedding links within a drag handle that do something other than start the drag.
addToGroup(JsString) Adds this instance to a group of related drag/drop objects. All instances belong to at least one group, and can belong to as many groups as needed.
applyConfig() Applies the configuration parameters that were passed into the constructor. This is supposed to happen at each level through the inheritance chain. So a DDProxy implentation will execute apply config on DDProxy, DD, and DragDrop in order to get all of the parameters that are available in each object.
clearConstraints() Clears any constraints applied to this instance. Also clears ticks since they can't exist independent of a constraint at this time.
clearTicks() Clears any tick interval defined for this instance
constrainTo(object, object, object) Initializes the drag drop object's constraints to restrict movement to a certain element. Usage:
var dd = new Ext.dd.DDProxy("dragDiv1", "proxytest",
            { dragElId: "existingProxyDiv" });
            dd.startDrag = function(){
            this.constrainTo("parent-id");
            };
            
Or you can initalize it using the Ext.Element object:
  Ext.get("dragDiv1").initDDProxy("proxytest", {dragElId: "existingProxyDiv"}, {
            startDrag : function(){
            this.constrainTo("parent-id");
            }
            });
            
endDrag(object) Called when we are done dragging the object
getDragEl() Returns a reference to the actual element to drag. By default this is the same as the html element, but it can be assigned to another element. An example of this can be found in Ext.dd.DDProxy
getEl() Returns a reference to the linked element
init(JsString, JsString, object) Sets up the DragDrop object. Must be called in the constructor of any Ext.dd.DragDrop subclass
initTarget(JsString, JsString, object) Initializes Targeting functionality only... the object does not get a mousedown handler.
isLocked() Returns true if this instance is locked, or the drag drop mgr is locked (meaning that all drag/drop is disabled on the page.)
isValidHandleChild(object) Checks the tag exclusion list to see if this click should be ignored
lock() Locks this instance
onAvailable() Override the onAvailable method to do what is needed after the initial position was determined.
onDrag(object) Abstract method called during the onMouseMove event while dragging an object.
onDragDrop(object, object) Abstract method called when this item is dropped on another DragDrop obj
onDragEnter(object, object) Abstract method called when this element fist begins hovering over another DragDrop obj
onDragOut(object, object) Abstract method called when we are no longer hovering over an element
onDragOver(object, object) Abstract method called when this element is hovering over another DragDrop obj
onInvalidDrop(object) Abstract method called when this item is dropped on an area with no drop target
onMouseDown(object) Called when a drag/drop obj gets a mousedown
onMouseUp(object) Called when a drag/drop obj gets a mouseup
removeFromGroup(JsString) Removes this instance from the supplied interaction group
removeInvalidHandleClass(JsString) Unsets an invalid css class
removeInvalidHandleId(JsString) Unsets an invalid handle id
removeInvalidHandleType(JsString) Unsets an excluded tag name set by addInvalidHandleType
resetConstraints(bool) Must be called if you manually reposition a dd element.
setDragElId(JsString) Allows you to specify that an element other than the linked element will be moved with the cursor during a drag
setHandleElId(JsString) Allows you to specify a child of the linked element that should be used to initiate the drag operation. An example of this would be if you have a content div with text and links. Clicking anywhere in the content area would normally start the drag operation. Use this method to specify that an element inside of the content div is the element that starts the drag operation.
setInitPosition(JsNumber, JsNumber) Stores the initial placement of the linked element.
setOuterHandleElId(JsString) Allows you to set an element outside of the linked element as a drag handle
setPadding(JsNumber, JsNumber, JsNumber, JsNumber) Configures the padding for the target zone in px. Effectively expands (or reduces) the virtual object size for targeting calculations. Supports css-style shorthand; if only one parameter is passed, all sides will have that padding, and if only two are passed, the top and bottom will have the first param, the left and right the second.
setXConstraint(JsNumber, JsNumber, object) By default, the element can be dragged any place on the screen. Use this method to limit the horizontal travel of the element. Pass in 0,0 for the parameters if you want to lock the drag to the y axis.
setYConstraint(JsNumber, JsNumber, object) By default, the element can be dragged any place on the screen. Set this to limit the vertical travel of the element. Pass in 0,0 for the parameters if you want to lock the drag to the x axis.
startDrag(JsNumber, JsNumber) Abstract method called after a drag/drop object is clicked and the drag or mousedown time thresholds have beeen met.
toString() toString method
unlock() Unlocks this instace
unreg() Removes all drag and drop hooks for this element

Properties

Name Description
available The available property is false until the linked dom element is accessible. Defaults to: false
config Configuration attributes passed into the constructor Defaults to: null
defaultPadding Provides default constraint padding to "constrainTo" elements. Defaults to: {left: 0, right: 0, top: 0, bottom: 0}
groups The group defines a logical collection of DragDrop objects that are related. Instances only get events when interacting with other DragDrop object in the same group. This lets us define multiple groups using a single DragDrop subclass if we want. An object in the format {'group1':true, 'group2':true} Defaults to: null
hasOuterHandles By default, drags can only be initiated if the mousedown occurs in the region the linked element is. This is done in part to work around a bug in some browsers that mis-report the mousedown if the previous mouseup happened outside of the window. This property is set to true if outer handles are defined. Defaults to false. Defaults to: false
id The id of the element associated with this object. This is what we refer to as the "linked element" because the size and position of this element is used to determine when the drag and drop objects have interacted. Defaults to: null
ignoreSelf Set to false to enable a DragDrop object to fire drag events while dragging over its own Element. Defaults to true - DragDrop objects do not by default fire drag events to themselves.
invalidHandleClasses An Array of CSS class names for elements to be considered in valid as drag handles. Defaults to: null
invalidHandleIds An object who's property names identify the IDs of elements to be considered invalid as drag handles. A non-null property value identifies the ID as invalid. For example, to prevent dragging from being initiated on element ID "foo", use:
{
            foo: true
            }
            
Defaults to: null
invalidHandleTypes An object who's property names identify HTML tags to be considered invalid as drag handles. A non-null property value identifies the tag as invalid. Defaults to the following value which prevents drag operations from being initiated by <a> elements:
{
            A: "A"
            }
            
Defaults to: null
isTarget By default, all instances can be a drop target. This can be disabled by setting isTarget to false. Defaults to: true
maintainOffset Maintain offsets when we resetconstraints. Set to true when you want the position of the element relative to its parent to stay the same when the page changes Defaults to: false
moveOnly When set to true, other DD objects in cooperating DDGroups do not receive notification events when this DD object is dragged over them. Defaults to: false
padding The padding configured for this drag and drop object for calculating the drop zone intersection with this object. An array containing the 4 padding values: [top, right, bottom, left] Defaults to: null
primaryButtonOnly By default the drag and drop instance will only respond to the primary button click (left button for a right-handed mouse). Set to true to allow drag and drop to start with any mouse click that is propogated by the browser Defaults to: true
xTicks Array of pixel locations the element will snap to if we specified a horizontal graduation/interval. This array is generated automatically when you define a tick interval. Defaults to: null
yTicks Array of pixel locations the element will snap to if we specified a vertical graduation/interval. This array is generated automatically when you define a tick interval. Defaults to: null
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