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- /*
- * Copyright 2000-2016 Vaadin Ltd.
- *
- * Licensed under the Apache License, Version 2.0 (the "License"); you may not
- * use this file except in compliance with the License. You may obtain a copy of
- * the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
- * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
- * License for the specific language governing permissions and limitations under
- * the License.
- */
- package com.vaadin.client.extensions;
-
- import java.util.List;
- import java.util.Map;
-
- import com.google.gwt.dom.client.DataTransfer;
- import com.google.gwt.dom.client.Element;
- import com.google.gwt.dom.client.NativeEvent;
- import com.vaadin.client.ComponentConnector;
- import com.vaadin.client.ServerConnector;
- import com.vaadin.event.dnd.DragSourceExtension;
- import com.vaadin.shared.ui.Connect;
- import com.vaadin.shared.ui.dnd.DragSourceRpc;
- import com.vaadin.shared.ui.dnd.DragSourceState;
-
- import elemental.events.Event;
- import elemental.events.EventListener;
- import elemental.events.EventTarget;
-
- /**
- * Extension to add drag source functionality to a widget for using HTML5 drag
- * and drop. Client side counterpart of {@link DragSourceExtension}.
- */
- @Connect(DragSourceExtension.class)
- public class DragSourceExtensionConnector extends AbstractExtensionConnector {
-
- private static final String CLASS_DRAGGABLE = "v-draggable";
-
- // Create event listeners
- private final EventListener dragStartListener = this::onDragStart;
- private final EventListener dragEndListener = this::onDragEnd;
-
- @Override
- protected void extend(ServerConnector target) {
- Element dragSourceElement = getDraggableElement();
-
- dragSourceElement.setDraggable(Element.DRAGGABLE_TRUE);
- dragSourceElement.addClassName(CLASS_DRAGGABLE);
-
- EventTarget dragSource = dragSourceElement.cast();
-
- // dragstart
- dragSource.addEventListener(Event.DRAGSTART, dragStartListener);
-
- // dragend
- dragSource.addEventListener(Event.DRAGEND, dragEndListener);
- }
-
- @Override
- public void onUnregister() {
- super.onUnregister();
-
- EventTarget dragSource = (EventTarget) getDraggableElement();
-
- // Remove listeners
- dragSource.removeEventListener(Event.DRAGSTART, dragStartListener);
- dragSource.removeEventListener(Event.DRAGEND, dragEndListener);
- }
-
- /**
- * Event handler for the {@code dragstart} event. Called when {@code
- * dragstart} event occurs.
- *
- * @param event
- * browser event to be handled
- */
- protected void onDragStart(Event event) {
- // Convert elemental event to have access to dataTransfer
- NativeEvent nativeEvent = (NativeEvent) event;
-
- // Set effectAllowed parameter
- if (getState().effectAllowed != null) {
- setEffectAllowed(nativeEvent.getDataTransfer(),
- getState().effectAllowed.getValue());
- }
-
- // Set data parameter
- List<String> types = getState().types;
- Map<String, String> data = getState().data;
- for (String format : types) {
- nativeEvent.getDataTransfer().setData(format, data.get(format));
- }
-
- // Initiate firing server side dragstart event when there is a
- // DragStartListener attached on the server side
- if (hasEventListener(DragSourceState.EVENT_DRAGSTART)) {
- getRpcProxy(DragSourceRpc.class).dragStart();
- }
- }
-
- /**
- * Event handler for the {@code dragend} event. Called when {@code dragend}
- * event occurs.
- *
- * @param event
- */
- protected void onDragEnd(Event event) {
- // Initiate server start dragend event when there is a DragEndListener
- // attached on the server side
- if (hasEventListener(DragSourceState.EVENT_DRAGEND)) {
- getRpcProxy(DragSourceRpc.class).dragEnd();
- }
- }
-
- /**
- * Finds the draggable element within the widget. By default, returns the
- * topmost element.
- *
- * @return the draggable element in the parent widget.
- */
- protected Element getDraggableElement() {
- return ((ComponentConnector) getParent()).getWidget().getElement();
- }
-
- private native void setEffectAllowed(DataTransfer dataTransfer,
- String effectAllowed)/*-{
- dataTransfer.effectAllowed = effectAllowed;
- }-*/;
-
- @Override
- public DragSourceState getState() {
- return (DragSourceState) super.getState();
- }
- }
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