Package com.vaadin.flow.component.dnd

Class DropEvent<T extends com.vaadin.flow.component.Component>

java.lang.Object

java.util.EventObject

com.vaadin.flow.component.ComponentEvent<T>

com.vaadin.flow.component.dnd.AbstractDnDEvent<T>

com.vaadin.flow.component.dnd.DropEvent<T>

Type Parameters:

T - Type of the drop target component.

All Implemented Interfaces:

Serializable

@DomEvent("drop")
public class DropEvent<T extends com.vaadin.flow.component.Component>
extends AbstractDnDEvent<T>

Server side drop event. Fired when an HTML5 drop happens on a valid drop target.

Since:

2.0

Author:

Vaadin Ltd

See Also:

• DropTarget.addDropListener(com.vaadin.flow.component.ComponentEventListener)
• Serialized Form

Field Summary

Fields inherited from class java.util.EventObject

source

Constructor Summary

Constructors

Constructor	Description
DropEvent(T source, boolean fromClient, String effectAllowed, int clientX, int clientY, int offsetX, int offsetY)	Creates a server side drop event.

Method Summary

Modifier and Type	Method	Description
Optional<Object>	getDragData()	Gets the server side drag data.
Optional<com.vaadin.flow.component.Component>	getDragSourceComponent()	Returns the drag source component if the drag originated from a component in the same UI as the drop target component, or an empty optional.
Optional<Integer>	getDragStartOffsetX()	Gets the x coordinate of the mouse pointer relative to the drag source element when the drag started.
Optional<Integer>	getDragStartOffsetY()	Gets the y coordinate of the mouse pointer relative to the drag source element when the drag started.
DropEffect	getDropEffect()	Get the desired dropEffect for the drop event.
EffectAllowed	getEffectAllowed()	Get the effectAllowed set by the drag source.
int	getOffsetX()	Gets the x coordinate of the drop position relative to the drop target element.
int	getOffsetY()	Gets the y coordinate of the drop position relative to the drop target element.

Methods inherited from class com.vaadin.flow.component.dnd.AbstractDnDEvent

getClientX, getClientY, getComponent

Methods inherited from class com.vaadin.flow.component.ComponentEvent

getSource, isFromClient, unregisterListener

Methods inherited from class java.util.EventObject

toString

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Details

DropEvent

public DropEvent(T source,
 boolean fromClient,
 @EventData("event.dataTransfer.effectAllowed")
 String effectAllowed,
 @EventData("event.clientX")
 int clientX,
 @EventData("event.clientY")
 int clientY,
 @EventData("event.clientX - event.currentTarget.getBoundingClientRect().left")
 int offsetX,
 @EventData("event.clientY - event.currentTarget.getBoundingClientRect().top")
 int offsetY)

Creates a server side drop event.

Parameters:

source - Component that received the drop.

fromClient - true if the event originated from the client side, false otherwise

effectAllowed - the effect allowed by the drag source

clientX - the x coordinate of the mouse pointer relative to the viewport

clientY - the y coordinate of the mouse pointer relative to the viewport

offsetX - the x coordinate of the mouse pointer relative to the drop target element

offsetY - the y coordinate of the mouse pointer relative to the drop target element

Method Details

getDragData

public Optional<Object> getDragData()

Gets the server side drag data. This data can be set during the drag start event on the server side and can be used to transfer data between drag source and drop target when they are in the same UI.

Returns:

Optional server side drag data if set and the drag source and the drop target are in the same UI, otherwise empty Optional.

getDropEffect

public DropEffect getDropEffect()

Get the desired dropEffect for the drop event.

Returns:

the drop effect set to the drop target, or null if nothing set

See Also:

• DropTarget.setDropEffect(DropEffect)

getEffectAllowed

public EffectAllowed getEffectAllowed()

Get the effectAllowed set by the drag source.

Returns:

the effect allowed by the drag source

See Also:

• DragSource.setEffectAllowed(EffectAllowed)

getDragSourceComponent

public Optional<com.vaadin.flow.component.Component> getDragSourceComponent()

Returns the drag source component if the drag originated from a component in the same UI as the drop target component, or an empty optional.

Returns:

Drag source component from the same UI or an empty optional.

getOffsetX

public int getOffsetX()

Gets the x coordinate of the drop position relative to the drop target element.

This is useful for positioning dropped items within the drop target container using absolute or relative positioning.

Returns:

the x coordinate relative to the drop target element

Since:

25.1

getOffsetY

public int getOffsetY()

Gets the y coordinate of the drop position relative to the drop target element.

This is useful for positioning dropped items within the drop target container using absolute or relative positioning.

Returns:

the y coordinate relative to the drop target element

Since:

25.1

getDragStartOffsetX

public Optional<Integer> getDragStartOffsetX()

Gets the x coordinate of the mouse pointer relative to the drag source element when the drag started.

This is useful for maintaining the relative grab position when positioning dropped items. For example, if you want items to appear where they were grabbed (not where the cursor is), subtract this value from getOffsetX().

Returns:

the drag start x offset if drag source is in the same UI, otherwise empty

Since:

25.1

getDragStartOffsetY

public Optional<Integer> getDragStartOffsetY()

Gets the y coordinate of the mouse pointer relative to the drag source element when the drag started.

This is useful for maintaining the relative grab position when positioning dropped items. For example, if you want items to appear where they were grabbed (not where the cursor is), subtract this value from getOffsetY().

Returns:

the drag start y offset if drag source is in the same UI, otherwise empty

Since:

25.1