nsIDragService

Method overview

Constants

Methods

Programmatically changes the drag position of the drag session. This is used on Mac and Windows to update the position of a popup being used as a drag image during the drag operation. It's not used on GTK, which handles the drag popup itself.

[noscript] void dragMoved(
  in long aX,
  in long aY
);

Parameters

aX

The X coordinate to which to move the popup being dragged.

aY

The Y coordinate to which to move the popup being dragged.

endDragSession()

Tells the Drag Service to end a drag session. This is called when an external drag occurs.

void endDragSession(
  in PRBool aDoneDrag  
);

Parameters

aDoneDrag

If aDoneDrag is true, the drag has finished, otherwise the drag has just left the window.

fireDragEventAtSource()

Fire a drag event at the source of the drag. This was changed in Gecko 43, see the following section.

void fireDragEventAtSource(
  in unsigned long aMsg 
); Obsolete since Gecko 43

Parameters

aMsg

One of the NS_DRAGDROP_* contants which was defined in widget/BasicEvents.h

Fire a drag event at the fource of the drag. This is available only from native code since Gecko 43.

[noscript] void fireDragEventAtSource(
  in mozilla::EventMessage aEventMessage
);

Parameters

aEventMessage

One of the event messages between eDragDropEventFirst and eDragDropEventLast defined in widget/EventMessageList.h

getCurrentSession()

Returns the current nsIDragSession.

nsIDragSession getCurrentSession();

Parameters

None.

Return value

The current drag session, or null if no drag is in progress.

invokeDragSession()

Starts a modal drag session with an array of transferables

void invokeDragSession(
  in nsIDOMNode aDOMNode,
  in nsISupportsArray aTransferables,
  in nsIScriptableRegion aRegion,
  in unsigned long aActionType 
);

Parameters

aDOMNode

The source node on which the drag gesture was started.

aTransferables

An array of transferables to be dragged.

aRegion

A region containing rectangles for cursor feedback, in window coordinates.

aActionType

Specified which of copy/move/link are allowed.

invokeDragSessionWithImage()

Starts a modal drag session using an image.

A custom image may be specified using the aImage argument. If this is supplied, the aImageX and aImageY arguments specify the offset within the image where the cursor would be positioned. That is, when the image is drawn, it is offset up and left the amount so that the cursor appears at that location within the image. If aImage is null, aImageX and aImageY are not used and the image is instead determined from the source node aDOMNode, and the offset calculated so that the initial location for the image appears in the same screen position as where the element is located. The node must be within a document.

Currently, supported images are all DOM nodes. If this is an HTML <image> or <canvas> element, the drag image is taken from the image data. If the element is in a document, it will be rendered at its displayed size, otherwise, it will be rendered at its real size. For other types of elements, the element is rendered into an offscreen buffer in the same manner as it is currently displayed. The document selection is hidden while drawing. The aDragEvent must be supplied as the current screen coordinates of the event are needed to calculate the image location.

void invokeDragSessionWithImage(
  in nsIDOMNode aDOMNode,
  in nsISupportsArray aTransferableArray,
  in nsIScriptableRegion aRegion,
  in unsigned long aActionType,
  in nsIDOMNode aImage,
  in long aImageX,
  in long aImageY,
  in nsIDOMDragEvent aDragEvent,
  in nsIDOMDataTransfer aDataTransfer 
);

Parameters

aDOMNode

The source node on which the drag gesture was started.

aTransferables

An array of transferables to be dragged.

aRegion

A region containing rectangles for cursor feedback, in window coordinates.

aActionType

Specified which of copy/move/link are allowed.

aImage

Image object.

aImageX

X position of image.

aImageY

Y position of image.

aDragEvent

The drag gesture event that initiated the drag.

aDataTransfer

A data transfer object that is available on the current drag session.

invokeDragSessionWithSelection()

Start a modal drag session using the selection as the drag image. The aDragEvent must be supplied as the current screen coordinates of the event are needed to calculate the image location.

void invokeDragSessionWithSelection(
  in nsISelection aSelection,
  in nsISupportsArray aTransferableArray,
  in unsigned long aActionType,
  in nsIDOMDragEvent aDragEvent,
  in nsIDOMDataTransfer aDataTransfer 
);

Parameters

aSelection

The selection that is to be dragged.

aTransferableArray

An array of transferables to be dragged.

aActionType

Specified which of copy/move/link are allowed

aDragEvent

The drag gesture event that initiated the drag.

aDataTransfer

A data transfer object that is available on the current drag session.

startDragSession()

Tells the Drag Service to start a drag session. This is called when an external drag occurs

void startDragSession();

Parameters

None.

suppress()

Increase dragging suppress level by one. This disables dragging if it is not already disabled.

void suppress();

Parameters

None.

unsuppress()

Decrease dragging suppress level by one. If level is zero, dragging is re-enabled.

void unsuppress();

Parameters

None.