Java tutorial
/* * Copyright 2011 Google 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 com.google.gwt.sample.mobilewebapp.client.desktop; import com.google.gwt.cell.client.AbstractCell; import com.google.gwt.cell.client.ValueUpdater; import com.google.gwt.core.client.GWT; import com.google.gwt.dom.client.DataTransfer; import com.google.gwt.dom.client.Element; import com.google.gwt.dom.client.EventTarget; import com.google.gwt.dom.client.NativeEvent; import com.google.gwt.event.dom.client.ClickEvent; import com.google.gwt.event.dom.client.ClickHandler; import com.google.gwt.event.dom.client.DragDropEventBase; import com.google.gwt.event.dom.client.DragLeaveEvent; import com.google.gwt.event.dom.client.DragLeaveHandler; import com.google.gwt.event.dom.client.DragOverEvent; import com.google.gwt.event.dom.client.DragOverHandler; import com.google.gwt.event.dom.client.DropEvent; import com.google.gwt.event.dom.client.DropHandler; import com.google.gwt.resources.client.ClientBundle; import com.google.gwt.resources.client.CssResource; import com.google.gwt.safehtml.client.SafeHtmlTemplates; import com.google.gwt.safehtml.shared.SafeHtml; import com.google.gwt.safehtml.shared.SafeHtmlBuilder; import com.google.gwt.sample.mobilewebapp.client.ui.DateButton; import com.google.gwt.sample.mobilewebapp.client.ui.EditorDecorator; import com.google.gwt.sample.mobilewebapp.presenter.task.TaskEditView; import com.google.gwt.sample.mobilewebapp.shared.TaskProxy; import com.google.gwt.sample.mobilewebapp.shared.TaskProxyImpl; import com.google.gwt.uibinder.client.UiBinder; import com.google.gwt.uibinder.client.UiField; import com.google.gwt.user.cellview.client.CellList; import com.google.gwt.user.cellview.client.HasKeyboardSelectionPolicy.KeyboardSelectionPolicy; import com.google.gwt.user.client.ui.Button; import com.google.gwt.user.client.ui.Composite; import com.google.gwt.user.client.ui.DecoratedPopupPanel; import com.google.gwt.user.client.ui.DockLayoutPanel; import com.google.gwt.user.client.ui.HTMLPanel; import com.google.gwt.user.client.ui.Label; import com.google.gwt.user.client.ui.PopupPanel; import com.google.gwt.user.client.ui.TextBoxBase; import com.google.gwt.user.client.ui.Widget; import com.google.web.bindery.requestfactory.gwt.client.RequestFactoryEditorDriver; import java.util.ArrayList; import java.util.List; /** * View used to edit a task. */ public class DesktopTaskEditView extends Composite implements TaskEditView { /** * The UiBinder interface. */ interface DesktopTaskEditViewUiBinder extends UiBinder<Widget, DesktopTaskEditView> { } /** * A ClientBundle that provides images for this widget. */ interface Resources extends ClientBundle { @Source("DesktopTaskEditView.css") Style style(); } /** * The styles used in this widget. */ interface Style extends CssResource { /** * Applies to the cells in the task template list. */ String taskTemplateCell(); } /** * The cell used to render task templates. */ static class TaskTemplateCell extends AbstractCell<TaskProxy> { interface Template extends SafeHtmlTemplates { @SafeHtmlTemplates.Template("<div class=\"{0}\" draggable=\"true\">" + "{1}<div style=\"font-size:80%;\">{2}</div></div>") SafeHtml task(String className, String name, String notes); } private Template template = GWT.create(Template.class); private final String className; public TaskTemplateCell(String className) { super("dragstart"); this.className = className; } @Override public void onBrowserEvent(Context context, Element parent, TaskProxy value, NativeEvent event, ValueUpdater<TaskProxy> valueUpdater) { if ("dragstart".equals(event.getType())) { // Save the ID of the TaskProxy. DataTransfer dataTransfer = event.getDataTransfer(); dataTransfer.setData("text", String.valueOf(context.getIndex())); // Set the image. dataTransfer.setDragImage(parent, 25, 15); } } @Override public void render(Context context, TaskProxy value, SafeHtmlBuilder sb) { if (value == null) { return; } String notes = value.getNotes(); sb.append(template.task(className, value.getName(), (notes == null) ? "" : notes)); } } interface Driver extends RequestFactoryEditorDriver<TaskProxy, DesktopTaskEditView> { } /** * The UiBinder used to generate the view. */ private static DesktopTaskEditViewUiBinder uiBinder = GWT.create(DesktopTaskEditViewUiBinder.class); /** * The glass panel used to lock the UI. */ private static PopupPanel glassPanel; /** * Show or hide the glass panel used to lock the UI will the task loads. * * @param visible true to show, false to hide */ private static void setGlassPanelVisible(boolean visible) { // Initialize the panel. if (glassPanel == null) { glassPanel = new DecoratedPopupPanel(false, true); glassPanel.setWidget(new Label("Loading...")); } if (visible) { // Show the loading panel. glassPanel.center(); } else { // Hide the loading panel. glassPanel.hide(); } } @UiField DockLayoutPanel dockLayoutPanel; /** * The panel that contains the edit form. */ @UiField HTMLPanel editForm; @UiField Button deleteButton; @UiField DateButton dueDateEditor; final EditorDecorator<String> nameEditor; @UiField @Ignore TextBoxBase nameField; @UiField Element nameViolation; @UiField TextBoxBase notesEditor; @UiField Button saveButton; @UiField(provided = true) final CellList<TaskProxy> templateList; @UiField Widget templateListContainer; private final Driver driver = GWT.create(Driver.class); /** * The {@link TaskEditView.Presenter} for this view. */ private Presenter presenter; private final Resources resources; /** * Construct a new {@link DesktopTaskEditView}. */ public DesktopTaskEditView() { // Initialize the styles. resources = GWT.create(Resources.class); resources.style().ensureInjected(); // Create the template list. templateList = createTaskTemplateList(); initWidget(uiBinder.createAndBindUi(this)); nameEditor = EditorDecorator.create(nameField.asEditor(), nameViolation); driver.initialize(this); // Hide the template list if it isn't supported. if (!DragDropEventBase.isSupported()) { dockLayoutPanel.setWidgetSize(templateListContainer, 0); } // Create a new task or modify the current task when done is pressed. saveButton.addClickHandler(new ClickHandler() { public void onClick(ClickEvent event) { if (presenter != null) { presenter.saveTask(); } } }); // Delete the current task or cancel when delete is pressed. deleteButton.addClickHandler(new ClickHandler() { public void onClick(ClickEvent event) { if (presenter != null) { presenter.deleteTask(); } } }); // Add the form as a drop target. editForm.addDomHandler(new DragOverHandler() { public void onDragOver(DragOverEvent event) { // Highlight the name and notes box. nameField.getElement().getStyle().setBackgroundColor("#ffa"); notesEditor.getElement().getStyle().setBackgroundColor("#ffa"); } }, DragOverEvent.getType()); editForm.addDomHandler(new DragLeaveHandler() { public void onDragLeave(DragLeaveEvent event) { EventTarget eventTarget = event.getNativeEvent().getEventTarget(); if (!Element.is(eventTarget)) { return; } Element target = Element.as(eventTarget); if (target == editForm.getElement()) { // Un-highlight the name and notes box. nameField.getElement().getStyle().clearBackgroundColor(); notesEditor.getElement().getStyle().clearBackgroundColor(); } } }, DragLeaveEvent.getType()); editForm.addDomHandler(new DropHandler() { public void onDrop(DropEvent event) { // Prevent the default text drop. event.preventDefault(); // Un-highlight the name and notes box. nameField.getElement().getStyle().clearBackgroundColor(); notesEditor.getElement().getStyle().clearBackgroundColor(); // Fill in the form. try { // Get the template the from the data transfer object. DataTransfer dataTransfer = event.getNativeEvent().getDataTransfer(); int templateIndex = Integer.parseInt(dataTransfer.getData("text")); TaskProxy template = templateList.getVisibleItem(templateIndex); nameField.setValue(template.getName()); notesEditor.setValue(template.getNotes()); } catch (NumberFormatException e) { // The user probably dragged something other than a template. } } }, DropEvent.getType()); } public RequestFactoryEditorDriver<TaskProxy, ?> getEditorDriver() { return driver; } public void setEditing(boolean isEditing) { if (isEditing) { deleteButton.setText("Delete item"); } else { deleteButton.setText("Cancel"); } } public void setLocked(boolean locked) { setGlassPanelVisible(locked); } public void setNameViolation(String message) { nameViolation.setInnerText(message); } public void setPresenter(Presenter presenter) { this.presenter = presenter; } private CellList<TaskProxy> createTaskTemplateList() { CellList<TaskProxy> list = new CellList<TaskProxy>( new TaskTemplateCell(resources.style().taskTemplateCell())); list.setKeyboardSelectionPolicy(KeyboardSelectionPolicy.DISABLED); // Create the templates. List<TaskProxy> templates = new ArrayList<TaskProxy>(); templates.add(new TaskProxyImpl("Call mom", null)); templates.add(new TaskProxyImpl("Register to vote", "Where is my polling location again?")); templates.add(new TaskProxyImpl("Replace air filter", "Size: 24x13x1")); templates.add(new TaskProxyImpl("Take out the trash", null)); list.setRowData(templates); return list; } }