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.Element; import com.google.gwt.event.dom.client.BlurEvent; import com.google.gwt.event.dom.client.BlurHandler; 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.DragHandler; 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.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.FocusEvent; import com.google.gwt.event.dom.client.FocusHandler; 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.HasAllFocusHandlers; import com.google.gwt.event.dom.client.HasAllGestureHandlers; import com.google.gwt.event.dom.client.HasAllKeyHandlers; 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.KeyDownEvent; import com.google.gwt.event.dom.client.KeyDownHandler; import com.google.gwt.event.dom.client.KeyPressEvent; import com.google.gwt.event.dom.client.KeyPressHandler; import com.google.gwt.event.dom.client.KeyUpEvent; import com.google.gwt.event.dom.client.KeyUpHandler; 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.user.client.DOM; import com.google.gwt.user.client.ui.impl.FocusImpl; /** * Abstract base class for most widgets that can receive keyboard focus. */ @SuppressWarnings("deprecation") public abstract class FocusWidget extends Widget implements SourcesClickEvents, HasClickHandlers, HasDoubleClickHandlers, HasFocus, HasEnabled, HasAllDragAndDropHandlers, HasAllFocusHandlers, HasAllGestureHandlers, HasAllKeyHandlers, HasAllMouseHandlers, HasAllTouchHandlers, SourcesMouseEvents { private static final FocusImpl impl = FocusImpl.getFocusImplForWidget(); /** * Gets the FocusImpl instance. * * @return impl */ protected static FocusImpl getFocusImpl() { return impl; } /** * Creates a new focus widget with no element. {@link #setElement(Element)} * must be called before any other methods. */ protected FocusWidget() { } /** * Creates a new focus widget that wraps the specified browser element. * * @param elem the element to be wrapped */ protected FocusWidget(Element elem) { setElement(elem); } public HandlerRegistration addBlurHandler(BlurHandler handler) { return addDomHandler(handler, BlurEvent.getType()); } 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 addFocusHandler(FocusHandler handler) { return addDomHandler(handler, FocusEvent.getType()); } /** * @deprecated Use {@link #addFocusHandler} instead */ @Deprecated public void addFocusListener(FocusListener listener) { ListenerWrapper.WrappedFocusListener.add(this, listener); } 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()); } /** * @deprecated Use {@link #addKeyDownHandler}, {@link * #addKeyUpHandler} and {@link #addKeyPressHandler} instead */ @Deprecated public void addKeyboardListener(KeyboardListener listener) { ListenerWrapper.WrappedKeyboardListener.add(this, listener); } public HandlerRegistration addKeyDownHandler(KeyDownHandler handler) { return addDomHandler(handler, KeyDownEvent.getType()); } public HandlerRegistration addKeyPressHandler(KeyPressHandler handler) { return addDomHandler(handler, KeyPressEvent.getType()); } public HandlerRegistration addKeyUpHandler(KeyUpHandler handler) { return addDomHandler(handler, KeyUpEvent.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()); } /** * Gets the tab index. * * @return the tab index */ public int getTabIndex() { return impl.getTabIndex(getElement()); } /** * Gets whether this widget is enabled. * * @return <code>true</code> if the widget is enabled */ public boolean isEnabled() { return !DOM.getElementPropertyBoolean(getElement(), "disabled"); } /** * @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 {@link #addFocusHandler} instead */ @Deprecated public void removeFocusListener(FocusListener listener) { ListenerWrapper.WrappedFocusListener.remove(this, listener); } /** * @deprecated Use the {@link HandlerRegistration#removeHandler} * method on the object returned by an add*Handler method instead */ @Deprecated public void removeKeyboardListener(KeyboardListener listener) { ListenerWrapper.WrappedKeyboardListener.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); } public void setAccessKey(char key) { DOM.setElementProperty(getElement(), "accessKey", "" + key); } /** * Sets whether this widget is enabled. * * @param enabled <code>true</code> to enable the widget, <code>false</code> * to disable it */ public void setEnabled(boolean enabled) { String tagName = getElement().getTagName().toLowerCase(); if (tagName.equals("input") || tagName.equals("textarea")) { if (enabled) { DOM.removeElementAttribute(getElement(), "readOnly"); } else { DOM.setElementProperty(getElement(), "readOnly", "readonly"); } } else { DOM.setElementPropertyBoolean(getElement(), "disabled", !enabled); } } public void setFocus(boolean focused) { if (focused) { impl.focus(getElement()); } else { impl.blur(getElement()); } } public void setTabIndex(int index) { impl.setTabIndex(getElement(), index); } @Override protected void onAttach() { super.onAttach(); // Accessibility: setting tab index to be 0 by default, ensuring element // appears in tab sequence. We must ensure that the element doesn't already // have a tabIndex set. This is not a problem for normal widgets, but when // a widget is used to wrap an existing static element, it can already have // a tabIndex. int tabIndex = getTabIndex(); if (-1 == tabIndex) { setTabIndex(0); } } }