com.vaadin.client.connectors.grid

Class GridDropTargetConnector

java.lang.Object

com.vaadin.client.ui.AbstractConnector

com.vaadin.client.extensions.AbstractExtensionConnector

com.vaadin.client.extensions.DropTargetExtensionConnector

com.vaadin.client.connectors.grid.GridDropTargetConnector

All Implemented Interfaces:

com.google.gwt.event.shared.EventHandler, StateChangeEvent.StateChangeHandler, ServerConnector, Connector, Serializable

Direct Known Subclasses:

TreeGridDropTargetConnector

public class GridDropTargetConnector
extends DropTargetExtensionConnector

Makes Grid an HTML5 drop target. This is the client side counterpart of GridDropTarget.

Since:

8.1

Author:

Vaadin Ltd

See Also:

Serialized Form

Field Summary

Fields inherited from class com.vaadin.client.extensions.DropTargetExtensionConnector

STYLE_SUFFIX_DRAG_BOTTOM, STYLE_SUFFIX_DRAG_CENTER, STYLE_SUFFIX_DRAG_TOP, STYLE_SUFFIX_DROPTARGET

Constructor Summary

Constructors

Constructor and Description
GridDropTargetConnector()

Method Summary

Modifier and Type	Method and Description
protected void	addDragOverStyle(com.google.gwt.dom.client.NativeEvent event) Add class that indicates that the component is a target while data is being dragged over it.
protected void	extend(ServerConnector target) Called when the extension is attached to its parent.
protected DropLocation	getDropLocation(com.google.gwt.dom.client.Element target, com.google.gwt.dom.client.NativeEvent event) Returns the location of the event within the row.
protected com.google.gwt.dom.client.Element	getDropTargetElement() Finds the drop target element within the widget.
protected elemental.json.JsonObject	getRowData(com.google.gwt.dom.client.TableRowElement row) Get the row data as json object for the given row.
GridDropTargetState	getState() Returns the shared state object for this connector.
protected com.google.gwt.dom.client.Element	getTargetElement(com.google.gwt.dom.client.Element source) Gets the target element for a dragover or drop event.
protected boolean	isDropAllowedByCriteriaScript(com.google.gwt.dom.client.NativeEvent event) Checks if a criteria script exists and, if yes, executes it.
protected boolean	isDroppingOnRowsPossible() Inspects whether the current drop would happen on the whole grid instead of specific row as the drop target.
protected void	onDragEnter(elemental.events.Event event) Event handler for the dragenter event.
protected void	removeDragOverStyle(com.google.gwt.dom.client.NativeEvent event) Remove the drag over indicator class name from the target element.
protected void	sendDropEventToServer(List<String> types, Map<String,String> data, String dropEffect, com.google.gwt.dom.client.NativeEvent dropEvent) Initiates a server RPC for the drop event.

Methods inherited from class com.vaadin.client.extensions.DropTargetExtensionConnector

addDropTargetStyle, onDragLeave, onDragOver, onDrop, onUnregister, removeDropTargetStyle

Methods inherited from class com.vaadin.client.extensions.AbstractExtensionConnector

setParent

Methods inherited from class com.vaadin.client.ui.AbstractConnector

addStateChangeHandler, addStateChangeHandler, createState, doInit, ensureHandlerManager, fireEvent, forceStateChange, getChildren, getConnection, getConnectorId, getParent, getResourceUrl, getRpcImplementations, getRpcProxy, getStateType, getTag, hasEventListener, init, isEnabled, onStateChanged, registerRpc, removeStateChangeHandler, removeStateChangeHandler, setChildren, setTag, unregisterRpc, updateEnabledState

Methods inherited from class java.lang.Object

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

Constructor Detail

GridDropTargetConnector

public GridDropTargetConnector()

Method Detail

extend

protected void extend(ServerConnector target)

Description copied from class: AbstractExtensionConnector

Called when the extension is attached to its parent. This method is only called once as an extension cannot be moved from one parent to another.

Overrides:

extend in class DropTargetExtensionConnector

Parameters:

target - The connector this extension extends

isDropAllowedByCriteriaScript

protected boolean isDropAllowedByCriteriaScript(com.google.gwt.dom.client.NativeEvent event)

Description copied from class: DropTargetExtensionConnector

Checks if a criteria script exists and, if yes, executes it. This method is protected, so subclasses as e.g. GridDropTargetConnector can override it to add additional script parameters.

Overrides:

isDropAllowedByCriteriaScript in class DropTargetExtensionConnector

Parameters:

event - browser event (dragEnter, dragOver, drop) that should be evaluated by the criteria script

Returns:

true if no script was given or if the script returned true, false otherwise.

isDroppingOnRowsPossible

protected boolean isDroppingOnRowsPossible()

Inspects whether the current drop would happen on the whole grid instead of specific row as the drop target. This is based on used drop mode, whether dropping on sorted grid rows is allowed (determined on server side and automatically updated to drop mode) and whether the grid is empty.

Returns:

true when the drop target is the whole grid, or false when it is one of the rows

sendDropEventToServer

protected void sendDropEventToServer(List<String> types,
                                     Map<String,String> data,
                                     String dropEffect,
                                     com.google.gwt.dom.client.NativeEvent dropEvent)

Description copied from class: DropTargetExtensionConnector

Initiates a server RPC for the drop event.

Overrides:

sendDropEventToServer in class DropTargetExtensionConnector

Parameters:

types - List of data types from DataTransfer.types object.

data - Map containing all types and corresponding data from the DataTransfer object.

dropEffect - The desired drop effect.

getRowData

protected elemental.json.JsonObject getRowData(com.google.gwt.dom.client.TableRowElement row)

Get the row data as json object for the given row.

Parameters:

row - table row element

Returns:

row data as json object for the given row

getDropLocation

protected DropLocation getDropLocation(com.google.gwt.dom.client.Element target,
                                       com.google.gwt.dom.client.NativeEvent event)

Returns the location of the event within the row.

Parameters:

target - drop target element

event - drop event

Returns:

the drop location to use

onDragEnter

protected void onDragEnter(elemental.events.Event event)

Description copied from class: DropTargetExtensionConnector

Event handler for the dragenter event.

Override this method in case custom handling for the dragstart event is required. If the drop is allowed, the event should prevent default.

Overrides:

onDragEnter in class DropTargetExtensionConnector

Parameters:

event - browser event to be handled

addDragOverStyle

protected void addDragOverStyle(com.google.gwt.dom.client.NativeEvent event)

Description copied from class: DropTargetExtensionConnector

Add class that indicates that the component is a target while data is being dragged over it.

This is triggered on dragenter and dragover events pending if the drop is possible. The drop is possible if the drop effect for the target and source do match and the drop criteria script evaluates to true or is not set.

Overrides:

addDragOverStyle in class DropTargetExtensionConnector

Parameters:

event - the dragenter or dragover event that triggered the indication.

removeDragOverStyle

protected void removeDragOverStyle(com.google.gwt.dom.client.NativeEvent event)

Description copied from class: DropTargetExtensionConnector

Remove the drag over indicator class name from the target element.

This is triggered on drop, dragleave and dragover events pending on whether the drop has happened or if it is not possible. The drop is not possible if the drop effect for the source and target don't match or if there is a drop criteria script that evaluates to false.

Overrides:

removeDragOverStyle in class DropTargetExtensionConnector

Parameters:

event - the event that triggered the removal of the indicator

getTargetElement

protected com.google.gwt.dom.client.Element getTargetElement(com.google.gwt.dom.client.Element source)

Gets the target element for a dragover or drop event.

Parameters:

source - the event target of the event

Returns:

the element that should be handled as the target of the event

getDropTargetElement

protected com.google.gwt.dom.client.Element getDropTargetElement()

Description copied from class: DropTargetExtensionConnector

Finds the drop target element within the widget. By default, returns the topmost element.

Overrides:

getDropTargetElement in class DropTargetExtensionConnector

Returns:

the drop target element in the parent widget.

getState

public GridDropTargetState getState()

Description copied from class: AbstractConnector

Returns the shared state object for this connector. Override this method to define the shared state type for your connector.

Specified by:

getState in interface ServerConnector

Overrides:

getState in class DropTargetExtensionConnector

Returns:

the current shared state (never null)