Java tutorial
/* * Copyright 2008 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.user.client.ui; import com.google.gwt.dom.client.Document; import com.google.gwt.dom.client.Element; import com.google.gwt.editor.client.IsEditor; import com.google.gwt.editor.client.LeafValueEditor; import com.google.gwt.editor.ui.client.adapters.HasTextEditor; import com.google.gwt.event.dom.client.ClickEvent; import com.google.gwt.event.dom.client.ClickHandler; import com.google.gwt.event.dom.client.DoubleClickEvent; import com.google.gwt.event.dom.client.DoubleClickHandler; import com.google.gwt.event.dom.client.DragEndEvent; import com.google.gwt.event.dom.client.DragEndHandler; import com.google.gwt.event.dom.client.DragEnterEvent; import com.google.gwt.event.dom.client.DragEnterHandler; import com.google.gwt.event.dom.client.DragEvent; import com.google.gwt.event.dom.client.DragLeaveEvent; import com.google.gwt.event.dom.client.DragLeaveHandler; import com.google.gwt.event.dom.client.DragHandler; import com.google.gwt.event.dom.client.DragOverEvent; import com.google.gwt.event.dom.client.DragOverHandler; import com.google.gwt.event.dom.client.DragStartEvent; import com.google.gwt.event.dom.client.DragStartHandler; import com.google.gwt.event.dom.client.DropEvent; import com.google.gwt.event.dom.client.DropHandler; import com.google.gwt.event.dom.client.GestureChangeEvent; import com.google.gwt.event.dom.client.GestureChangeHandler; import com.google.gwt.event.dom.client.GestureEndEvent; import com.google.gwt.event.dom.client.GestureEndHandler; import com.google.gwt.event.dom.client.GestureStartEvent; import com.google.gwt.event.dom.client.GestureStartHandler; import com.google.gwt.event.dom.client.HasAllDragAndDropHandlers; import com.google.gwt.event.dom.client.HasAllGestureHandlers; import com.google.gwt.event.dom.client.HasAllMouseHandlers; import com.google.gwt.event.dom.client.HasAllTouchHandlers; import com.google.gwt.event.dom.client.HasClickHandlers; import com.google.gwt.event.dom.client.HasDoubleClickHandlers; import com.google.gwt.event.dom.client.MouseDownEvent; import com.google.gwt.event.dom.client.MouseDownHandler; import com.google.gwt.event.dom.client.MouseMoveEvent; import com.google.gwt.event.dom.client.MouseMoveHandler; import com.google.gwt.event.dom.client.MouseOutEvent; import com.google.gwt.event.dom.client.MouseOutHandler; import com.google.gwt.event.dom.client.MouseOverEvent; import com.google.gwt.event.dom.client.MouseOverHandler; import com.google.gwt.event.dom.client.MouseUpEvent; import com.google.gwt.event.dom.client.MouseUpHandler; import com.google.gwt.event.dom.client.MouseWheelEvent; import com.google.gwt.event.dom.client.MouseWheelHandler; import com.google.gwt.event.dom.client.TouchCancelEvent; import com.google.gwt.event.dom.client.TouchCancelHandler; import com.google.gwt.event.dom.client.TouchEndEvent; import com.google.gwt.event.dom.client.TouchEndHandler; import com.google.gwt.event.dom.client.TouchMoveEvent; import com.google.gwt.event.dom.client.TouchMoveHandler; import com.google.gwt.event.dom.client.TouchStartEvent; import com.google.gwt.event.dom.client.TouchStartHandler; import com.google.gwt.event.shared.HandlerRegistration; import com.google.gwt.i18n.client.BidiUtils; import com.google.gwt.i18n.client.HasDirection; import com.google.gwt.i18n.shared.DirectionEstimator; /** * A widget that contains arbitrary text, <i>not</i> interpreted as HTML. * * This widget uses a <div> element, causing it to be displayed with block * layout. * * <p> * <h3>Built-in Bidi Text Support</h3> * This widget is capable of automatically adjusting its direction according to * its content. This feature is controlled by {@link #setDirectionEstimator} or * passing a DirectionEstimator parameter to the constructor, and is off by * default. * </p> * * <h3>CSS Style Rules</h3> * <ul class='css'> * <li>.gwt-Label { }</li> * </ul> * * <p> * <h3>Example</h3> * {@example com.google.gwt.examples.HTMLExample} * </p> */ @SuppressWarnings("deprecation") public class Label extends LabelBase<String> implements HasDirectionalText, HasDirection, HasClickHandlers, HasDoubleClickHandlers, SourcesClickEvents, SourcesMouseEvents, HasAllDragAndDropHandlers, HasAllGestureHandlers, HasAllMouseHandlers, HasAllTouchHandlers, IsEditor<LeafValueEditor<String>> { public static final DirectionEstimator DEFAULT_DIRECTION_ESTIMATOR = DirectionalTextHelper.DEFAULT_DIRECTION_ESTIMATOR; /** * Creates a Label widget that wraps an existing <div> or <span> * element. * * This element must already be attached to the document. If the element is * removed from the document, you must call * {@link RootPanel#detachNow(Widget)}. * * @param element the element to be wrapped */ public static Label wrap(Element element) { // Assert that the element is attached. assert Document.get().getBody().isOrHasChild(element); Label label = new Label(element); // Mark it attached and remember it for cleanup. label.onAttach(); RootPanel.detachOnWindowClose(label); return label; } private LeafValueEditor<String> editor; /** * Creates an empty label. */ public Label() { super(false); setStyleName("gwt-Label"); } /** * Creates a label with the specified text. * * @param text the new label's text */ public Label(String text) { this(); setText(text); } /** * Creates a label with the specified text and direction. * * @param text the new label's text * @param dir the text's direction. Note that {@code DEFAULT} means direction * should be inherited from the widget's parent element. */ public Label(String text, Direction dir) { this(); setText(text, dir); } /** * Creates a label with the specified text and a default direction estimator. * * @param text the new label's text * @param directionEstimator A DirectionEstimator object used for automatic * direction adjustment. For convenience, * {@link #DEFAULT_DIRECTION_ESTIMATOR} can be used. */ public Label(String text, DirectionEstimator directionEstimator) { this(); setDirectionEstimator(directionEstimator); setText(text); } /** * Creates a label with the specified text. * * @param text the new label's text * @param wordWrap <code>false</code> to disable word wrapping */ public Label(String text, boolean wordWrap) { this(text); setWordWrap(wordWrap); } /** * This constructor may be used by subclasses to explicitly use an existing * element. This element must be either a <div> or <span> element. * * @param element the element to be used */ protected Label(Element element) { super(element); } public HandlerRegistration addClickHandler(ClickHandler handler) { return addDomHandler(handler, ClickEvent.getType()); } /** * @deprecated Use {@link #addClickHandler} instead */ @Deprecated public void addClickListener(ClickListener listener) { ListenerWrapper.WrappedClickListener.add(this, listener); } public HandlerRegistration addDoubleClickHandler(DoubleClickHandler handler) { return addDomHandler(handler, DoubleClickEvent.getType()); } public HandlerRegistration addDragEndHandler(DragEndHandler handler) { return addBitlessDomHandler(handler, DragEndEvent.getType()); } public HandlerRegistration addDragEnterHandler(DragEnterHandler handler) { return addBitlessDomHandler(handler, DragEnterEvent.getType()); } public HandlerRegistration addDragHandler(DragHandler handler) { return addBitlessDomHandler(handler, DragEvent.getType()); } public HandlerRegistration addDragLeaveHandler(DragLeaveHandler handler) { return addBitlessDomHandler(handler, DragLeaveEvent.getType()); } public HandlerRegistration addDragOverHandler(DragOverHandler handler) { return addBitlessDomHandler(handler, DragOverEvent.getType()); } public HandlerRegistration addDragStartHandler(DragStartHandler handler) { return addBitlessDomHandler(handler, DragStartEvent.getType()); } public HandlerRegistration addDropHandler(DropHandler handler) { return addBitlessDomHandler(handler, DropEvent.getType()); } public HandlerRegistration addGestureChangeHandler(GestureChangeHandler handler) { return addDomHandler(handler, GestureChangeEvent.getType()); } public HandlerRegistration addGestureEndHandler(GestureEndHandler handler) { return addDomHandler(handler, GestureEndEvent.getType()); } public HandlerRegistration addGestureStartHandler(GestureStartHandler handler) { return addDomHandler(handler, GestureStartEvent.getType()); } public HandlerRegistration addMouseDownHandler(MouseDownHandler handler) { return addDomHandler(handler, MouseDownEvent.getType()); } /** * @deprecated Use {@link #addMouseOverHandler}, * {@link #addMouseMoveHandler}, {@link #addMouseDownHandler}, * {@link #addMouseUpHandler} and {@link #addMouseOutHandler} instead */ @Deprecated public void addMouseListener(MouseListener listener) { ListenerWrapper.WrappedMouseListener.add(this, listener); } public HandlerRegistration addMouseMoveHandler(MouseMoveHandler handler) { return addDomHandler(handler, MouseMoveEvent.getType()); } public HandlerRegistration addMouseOutHandler(MouseOutHandler handler) { return addDomHandler(handler, MouseOutEvent.getType()); } public HandlerRegistration addMouseOverHandler(MouseOverHandler handler) { return addDomHandler(handler, MouseOverEvent.getType()); } public HandlerRegistration addMouseUpHandler(MouseUpHandler handler) { return addDomHandler(handler, MouseUpEvent.getType()); } public HandlerRegistration addMouseWheelHandler(MouseWheelHandler handler) { return addDomHandler(handler, MouseWheelEvent.getType()); } /** * @deprecated Use {@link #addMouseWheelHandler} instead */ @Deprecated public void addMouseWheelListener(MouseWheelListener listener) { ListenerWrapper.WrappedMouseWheelListener.add(this, listener); } public HandlerRegistration addTouchCancelHandler(TouchCancelHandler handler) { return addDomHandler(handler, TouchCancelEvent.getType()); } public HandlerRegistration addTouchEndHandler(TouchEndHandler handler) { return addDomHandler(handler, TouchEndEvent.getType()); } public HandlerRegistration addTouchMoveHandler(TouchMoveHandler handler) { return addDomHandler(handler, TouchMoveEvent.getType()); } public HandlerRegistration addTouchStartHandler(TouchStartHandler handler) { return addDomHandler(handler, TouchStartEvent.getType()); } public LeafValueEditor<String> asEditor() { if (editor == null) { editor = HasTextEditor.of(this); } return editor; } /** * Gets the widget element's direction. * @deprecated Use {@link #getTextDirection} instead */ @Deprecated public Direction getDirection() { return BidiUtils.getDirectionOnElement(getElement()); } public String getText() { return directionalTextHelper.getTextOrHtml(false); } public Direction getTextDirection() { return directionalTextHelper.getTextDirection(); } /** * @deprecated Use the {@link HandlerRegistration#removeHandler} method on * the object returned by {@link #addClickHandler} instead */ @Deprecated public void removeClickListener(ClickListener listener) { ListenerWrapper.WrappedClickListener.remove(this, listener); } /** * @deprecated Use the {@link HandlerRegistration#removeHandler} * method on the object returned by an add*Handler method instead */ @Deprecated public void removeMouseListener(MouseListener listener) { ListenerWrapper.WrappedMouseListener.remove(this, listener); } /** * @deprecated Use the {@link HandlerRegistration#removeHandler} * method on the object returned by {@link #addMouseWheelHandler} instead */ @Deprecated public void removeMouseWheelListener(MouseWheelListener listener) { ListenerWrapper.WrappedMouseWheelListener.remove(this, listener); } /** * Sets the widget element's direction. * @deprecated Use {@link #setDirectionEstimator} and / or pass explicit * direction to {@link #setText} instead */ @Deprecated public void setDirection(Direction direction) { directionalTextHelper.setDirection(direction); updateHorizontalAlignment(); } /** * Sets the label's content to the given text. * <p> * Doesn't change the widget's direction or horizontal alignment if {@code * directionEstimator} is null. Otherwise, the widget's direction is set using * the estimator, and its alignment may therefore change as described in * {@link #setText(String, com.google.gwt.i18n.client.HasDirection.Direction) setText(String, Direction)}. * * @param text the widget's new text */ public void setText(String text) { directionalTextHelper.setTextOrHtml(text, false); updateHorizontalAlignment(); } /** * Sets the label's content to the given text, applying the given direction. * <p> * This will have the following effect on the horizontal alignment: * <ul> * <li> If the automatic alignment setting is ALIGN_CONTENT_START or * ALIGN_CONTENT_END, the horizontal alignment will be set to match the start * or end edge, respectively, of the new direction (the {@code dir} * parameter). If that is DEFAULT, the locale direction is used. * <li> Otherwise, the horizontal alignment value is not changed, but the * effective alignment may nevertheless change according to the usual HTML * rules, i.e. it will match the start edge of the new direction if the widget * element is a <div> and has no explicit alignment value even by * inheritance. * </ul> * * @param text the widget's new text * @param dir the text's direction. Note: {@code Direction.DEFAULT} means * direction should be inherited from the widget's parent element. */ public void setText(String text, Direction dir) { directionalTextHelper.setTextOrHtml(text, dir, false); updateHorizontalAlignment(); } }