Java tutorial
/* * Copyright 2015 JBoss, by Red Hat, Inc * * 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 org.uberfire.ext.layout.editor.client.dnd; import com.google.gwt.core.client.GWT; import com.google.gwt.event.dom.client.*; import com.google.gwt.event.shared.HandlerRegistration; import com.google.gwt.user.client.ui.FlowPanel; import org.gwtbootstrap3.client.ui.Label; import org.uberfire.ext.layout.editor.client.components.*; import org.uberfire.ext.layout.editor.client.resources.WebAppResource; import org.uberfire.ext.layout.editor.client.resources.i18n.CommonConstants; import org.uberfire.ext.layout.editor.client.row.RowView; import org.uberfire.ext.layout.editor.client.structure.ColumnEditorWidget; public class DropColumnPanel extends FlowPanel { private DndDataJSONConverter converter = new DndDataJSONConverter(); private final ColumnEditorWidget parent; public DropColumnPanel(final ColumnEditorWidget parent) { super(); this.parent = parent; Label label = GWT.create(Label.class); label.setText(CommonConstants.INSTANCE.Column()); this.add(label); addCSSClass(WebAppResource.INSTANCE.CSS().dropInactive()); addDragOverHandler(new DragOverHandler() { @Override public void onDragOver(DragOverEvent event) { dragOverHandler(); } }); addDragLeaveHandler(new DragLeaveHandler() { @Override public void onDragLeave(DragLeaveEvent event) { dragLeaveHandler(); } }); addDropHandler(new DropHandler() { @Override public void onDrop(DropEvent event) { dropHandler(event); } }); } void dropHandler(DropEvent event) { event.preventDefault(); LayoutDragComponent component = converter.readJSONDragComponent(event.getData(LayoutDragComponent.FORMAT)); if (component instanceof GridLayoutDragComponent) { handleGridDrop(((GridLayoutDragComponent) component).getSpan()); } else { handleExternalLayoutDragComponent(component); } dragLeaveHandler(); } private void handleExternalLayoutDragComponent(LayoutDragComponent layoutDragComponent) { if (layoutDragComponent != null) { if (layoutDragComponent instanceof HasOnDropNotification) { ((HasOnDropNotification) layoutDragComponent).onDropComponent(); } handleLayoutDrop(layoutDragComponent); } } void dragOverHandler() { removeCSSClass(WebAppResource.INSTANCE.CSS().dropInactive()); addCSSClass(WebAppResource.INSTANCE.CSS().dropBorder()); } void addCSSClass(String className) { getElement().addClassName(className); } void dragLeaveHandler() { removeCSSClass(WebAppResource.INSTANCE.CSS().dropBorder()); addCSSClass(WebAppResource.INSTANCE.CSS().dropInactive()); } void removeCSSClass(String className) { getElement().removeClassName(className); } private void handleLayoutDrop(LayoutDragComponent layoutDragComponent) { parent.getWidget().remove(this); parent.getWidget().add(new LayoutComponentView(parent, layoutDragComponent, true)); } private void handleGridDrop(String grid) { parent.getWidget().remove(this); parent.getWidget().add(new RowView(parent, grid, this)); } private HandlerRegistration addDropHandler(DropHandler handler) { return addBitlessDomHandler(handler, DropEvent.getType()); } private HandlerRegistration addDragOverHandler(DragOverHandler handler) { return addBitlessDomHandler(handler, DragOverEvent.getType()); } private HandlerRegistration addDragLeaveHandler(DragLeaveHandler handler) { return addBitlessDomHandler(handler, DragLeaveEvent.getType()); } public void setConverter(DndDataJSONConverter converter) { this.converter = converter; } }