DragSource (Vaadin Platform (vaadin-platform-javadoc) 14.3.7 API)

Type Parameters:

T - the type of the drag source component

All Superinterfaces:

HasElement, Serializable
```
@JavaScript(value="frontend://dndConnector.js")
 @JsModule(value="./dndConnector-es6.js")
public interface DragSource<T extends Component>
extends HasElement
```
Mixin interface that provides basic drag source API for any component.
This can be used by either implementing this interface, or with the static API create(Component), configure(Component) or configure(Component, boolean).
NOTE: Starting a drag from a component that has contents inside shadow dom does not work in Firefox due to https://bugzilla.mozilla .org/show_bug.cgi?id=1521471. Thus currently Vaadin components like TextField, DatePicker and ComboBox cannot be dragged by the user in Firefox.

Since:

2.0

Author:

Vaadin Ltd

See Also:

DropTarget

Method Summary

All Methods Static Methods Instance Methods Default Methods
Modifier and Type	Method and Description
`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.
`default Registration`	`addDragStartListener(ComponentEventListener<DragStartEvent<T>> listener)` Attaches dragstart listener for the current drag source.
`static <T extends Component> DragSource<T>`	`configure(T component)` Gives access to the generic drag source API for the given component.
`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.
`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.
`default Object`	`getDragData()` Get server side drag data.
`default Element`	`getDraggableElement()` Returns the element where the `draggable` attribute is applied, making it draggable by the user.
`default T`	`getDragSourceComponent()` Returns the drag source component.
`default EffectAllowed`	`getEffectAllowed()` Returns the allowed effects for the current drag source element.
`default Element`	`getElement()` Gets the element associated with this instance.
`default boolean`	`isDraggable()` Is this component currently draggable.
`default void`	`setDragData(Object data)` Set server side drag data.
`default void`	`setDraggable(boolean draggable)` Sets this component as draggable.
`default void`	`setEffectAllowed(EffectAllowed effect)` Sets the allowed effects for the current drag source element.

- Method Detail
  - 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.
  - 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.

Interface DragSource<T extends Component>

Method Summary

Method Detail

create

configure

configure

getDragSourceComponent

getElement

getDraggableElement

setDraggable

isDraggable

setDragData

getDragData

setEffectAllowed

getEffectAllowed

addDragStartListener

addDragEndListener