Method Details

• create

  static <T extends Component> DragSource<T> create(T component)

  Makes the given component draggable and gives access to the generic drag source API for the component.

  The given component will be always set as draggable, if this is not desired, use either method configure(Component, boolean) or setDraggable(boolean).

  Type Parameters:

  T - the type of the component

  Parameters:

  component - the component to make draggable

  Returns:

  drag source API mapping to the component

  See Also:

  • configure(Component)
  • configure(Component, boolean)

• configure

  static <T extends Component> DragSource<T> configure(T component)

  Gives access to the generic drag source API for the given component.

  Unlike create(Component) and configure(Component, boolean), this method does not change the active drop target status of the given component.

  Type Parameters:

  T - the type of the component

  Parameters:

  component - the component to make draggable

  Returns:

  drag source API mapping to the component

  See Also:

  • create(Component)
  • configure(Component, boolean)

• configure

  static <T extends Component> DragSource<T> configure(T component, boolean draggable)

  Gives access to the generic drag source API for the given component and applies the given draggable status to it.

  This method is a shorthand for calling configure(Component) and setDraggable(boolean).

  The component draggable state can be changed later on with setDraggable(boolean).

  Type Parameters:

  T - the type of the component

  Parameters:

  component - the component to make draggable

  draggable - true to make draggable, false to not

  Returns:

  drag source API mapping to the component

  See Also:

  • create(Component)
  • configure(Component, boolean)

• getDragSourceComponent

  default T getDragSourceComponent()

  Returns the drag source component. This component is used in the drag start and end events, and set as active drag source for the UI when dragged.

  The default implementation of this method returns this. This method exists for type safe access for the drag source component.

  Returns:

  the drag source component

• getElement

  default Element getElement()

  Description copied from interface: HasElement

  Gets the element associated with this instance.

  Specified by:

  getElement in interface HasElement

  Returns:

  the element associated with this instance

• getDraggableElement

  default Element getDraggableElement()

  Returns the element where the draggable attribute is applied, making it draggable by the user. By default it is the element of the component returned by getDragSourceComponent().

  Override this method to provide another element to be draggable instead of the root element of the component.

  Returns:

  the element made draggable

  Since:

  2.1

• setDraggable

  default void setDraggable(boolean draggable)

  Sets this component as draggable. By default it is not.

  Parameters:

  draggable - true for enable dragging, false to prevent

• isDraggable

  default boolean isDraggable()

  Is this component currently draggable. By default it is not.

  Returns:

  true draggable, false if not

• setDragData

  default void setDragData(Object data)

  Set server side drag data. This data is available in the drop event and can be used to transfer data between drag source and DropTarget if they are in the same UI.

  The drag data can be set also in the drag start event listener added with addDragStartListener(ComponentEventListener) using DragStartEvent.setDragData(Object).

  Parameters:

  data - Data to transfer to drop event.

  See Also:

  • DropEvent.getDragData()
  • DragStartEvent.setDragData(Object)
  • DragEndEvent.clearDragData()

• getDragData

  default Object getDragData()

  Get server side drag data. This data is available in the drop event and can be used to transfer data between drag source and drop target if they are in the same UI.

  Returns:

  Server side drag data if set, otherwise null.

• setEffectAllowed

  default void setEffectAllowed(EffectAllowed effect)

  Sets the allowed effects for the current drag source element. Used for setting client side DataTransfer.effectAllowed parameter for the drag event.

  By default the value is EffectAllowed.UNINITIALIZED which is equivalent to EffectAllowed.ALL.

  NOTE: The effect should be set in advance, setting it after the user has started dragging and the DragStartEvent has been fired is too late - it will take effect only for next drag operation.

  NOTE 2: Edge, Safari and IE11 will allow the drop to occur even when the effect allowed does not match the drop effect set on the drop target. Chrome and Firefox prevent the drop if those do not match.

  Parameters:

  effect - Effects to allow for this draggable element. Cannot be null.

  See Also:

  • MDN web docs for more information.

• getEffectAllowed

  default EffectAllowed getEffectAllowed()

  Returns the allowed effects for the current drag source element. Used to set client side DataTransfer.effectAllowed parameter for the drag event.

  Returns:

  effects that are allowed for this draggable element.

• setDragImage

  default void setDragImage(Component dragImage)

  Sets the drag image for the current drag source element. The image is applied automatically in the next drag start event in the browser. Drag image is shown by default with zero offset which means that pointer location is in the top left corner of the image.

  com.vaadin.flow.component.html.Image is fully supported as a drag image component. Other components can be used as well, but the support may vary between browsers. If given component is visible element in the viewport, browser can show it as a drag image.

  Parameters:

  dragImage - the image to be used as drag image or null to remove it

  See Also:

  • MDN web docs for more information.

• setDragImage

  default void setDragImage(Component dragImage, int offsetX, int offsetY)

  Sets the drag image for the current drag source element. The image is applied automatically in the next drag start event in the browser. Coordinates define the offset of the pointer location from the top left corner of the image.

  com.vaadin.flow.component.html.Image is fully supported as a drag image component. Other components can be used as well, but the support may vary between browsers. If given component is visible element in the viewport, browser can show it as a drag image.

  Parameters:

  dragImage - the image to be used as drag image or null to remove it

  offsetX - the x-offset of the drag image

  offsetY - the y-offset of the drag image

  See Also:

  • MDN web docs for more information.

• getDragImage

  default Component getDragImage()

  Get server side drag image. This image is applied automatically in the next drag start event in the browser.

  Returns:

  Server side drag image if set, otherwise null.

• addDragStartListener

  default Registration addDragStartListener(ComponentEventListener<DragStartEvent<T>> listener)

  Attaches dragstart listener for the current drag source. The listener is triggered when dragstart event happens on the client side.

  Parameters:

  listener - Listener to handle dragstart event.

  Returns:

  Handle to be used to remove this listener.

• addDragEndListener

  default Registration addDragEndListener(ComponentEventListener<DragEndEvent<T>> listener)

  Attaches dragend listener for the current drag source.The listener is triggered when dragend event happens on the client side.

  Parameters:

  listener - Listener to handle dragend event.

  Returns:

  Handle to be used to remove this listener.