DragAndDropTarget Class Reference

Inheritance diagram for DragAndDropTarget:

Toolbar List of all members.

Detailed Description

Components derived from this class can have things dropped onto them by a DragAndDropContainer.

To create a component that can receive things drag-and-dropped by a DragAndDropContainer, derive your component from this class, and make sure that it is somewhere inside a DragAndDropContainer component.

Note: If all that you need to do is to respond to files being drag-and-dropped from the operating system onto your component, you don't need any of these classes: instead see the FileDragAndDropTarget class.

See also:
DragAndDropContainer, FileDragAndDropTarget


Public Member Functions

virtual ~DragAndDropTarget ()
 Destructor.
virtual bool isInterestedInDragSource (const String &sourceDescription, Component *sourceComponent)=0
 Callback to check whether this target is interested in the type of object being dragged.
virtual void itemDragEnter (const String &sourceDescription, Component *sourceComponent, int x, int y)
 Callback to indicate that something is being dragged over this component.
virtual void itemDragMove (const String &sourceDescription, Component *sourceComponent, int x, int y)
 Callback to indicate that the user is dragging something over this component.
virtual void itemDragExit (const String &sourceDescription, Component *sourceComponent)
 Callback to indicate that something has been dragged off the edge of this component.
virtual void itemDropped (const String &sourceDescription, Component *sourceComponent, int x, int y)=0
 Callback to indicate that the user has dropped something onto this component.
virtual bool shouldDrawDragImageWhenOver ()
 Overriding this allows the target to tell the drag container whether to draw the drag image while the cursor is over it.

Constructor & Destructor Documentation

virtual DragAndDropTarget::~DragAndDropTarget (   )  [virtual]
 

Destructor.

Member Function Documentation

virtual bool DragAndDropTarget::isInterestedInDragSource (  const String &  sourceDescription,
Component *  sourceComponent
)  [pure virtual]
 

Callback to check whether this target is interested in the type of object being dragged.

Parameters:
sourceDescription the description string passed into DragAndDropContainer::startDragging()
sourceComponent the component that was passed into DragAndDropContainer::startDragging()
Returns:
true if this component wants to receive the other callbacks regarging this type of object; if it returns false, no other callbacks will be made.

Implemented in Toolbar.

virtual void DragAndDropTarget::itemDragEnter (  const String &  sourceDescription,
Component *  sourceComponent,
int  x,
int  y
)  [virtual]
 

Callback to indicate that something is being dragged over this component.

This gets called when the user moves the mouse into this component while dragging something.

Use this callback as a trigger to make your component repaint itself to give the user feedback about whether the item can be dropped here or not.

Parameters:
sourceDescription the description string passed into DragAndDropContainer::startDragging()
sourceComponent the component that was passed into DragAndDropContainer::startDragging()
x the mouse x position, relative to this component
y the mouse y position, relative to this component
See also:
itemDragExit

virtual void DragAndDropTarget::itemDragMove (  const String &  sourceDescription,
Component *  sourceComponent,
int  x,
int  y
)  [virtual]
 

Callback to indicate that the user is dragging something over this component.

This gets called when the user moves the mouse over this component while dragging something. Normally overriding itemDragEnter() and itemDragExit() are enough, but this lets you know what happens in-between.

Parameters:
sourceDescription the description string passed into DragAndDropContainer::startDragging()
sourceComponent the component that was passed into DragAndDropContainer::startDragging()
x the mouse x position, relative to this component
y the mouse y position, relative to this component

Reimplemented in Toolbar.

virtual void DragAndDropTarget::itemDragExit (  const String &  sourceDescription,
Component *  sourceComponent
)  [virtual]
 

Callback to indicate that something has been dragged off the edge of this component.

This gets called when the user moves the mouse out of this component while dragging something.

If you've used itemDragEnter() to repaint your component and give feedback, use this as a signal to repaint it in its normal state.

Parameters:
sourceDescription the description string passed into DragAndDropContainer::startDragging()
sourceComponent the component that was passed into DragAndDropContainer::startDragging()
See also:
itemDragEnter

Reimplemented in Toolbar.

virtual void DragAndDropTarget::itemDropped (  const String &  sourceDescription,
Component *  sourceComponent,
int  x,
int  y
)  [pure virtual]
 

Callback to indicate that the user has dropped something onto this component.

When the user drops an item this get called, and you can use the description to work out whether your object wants to deal with it or not.

Note that after this is called, the itemDragExit method may not be called, so you should clean up in here if there's anything you need to do when the drag finishes.

Parameters:
sourceDescription the description string passed into DragAndDropContainer::startDragging()
sourceComponent the component that was passed into DragAndDropContainer::startDragging()
x the mouse x position, relative to this component
y the mouse y position, relative to this component

Implemented in Toolbar.

virtual bool DragAndDropTarget::shouldDrawDragImageWhenOver (   )  [virtual]
 

Overriding this allows the target to tell the drag container whether to draw the drag image while the cursor is over it.

By default it returns true, but if you return false, then the normal drag image will not be shown when the cursor is over this target.

The documentation for this class was generated from the following file: