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/*
 * Copyright 2009 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.InputElement;
import com.google.gwt.dom.client.LabelElement;
import com.google.gwt.editor.client.IsEditor;
import com.google.gwt.editor.client.LeafValueEditor;
import com.google.gwt.editor.client.adapters.TakesValueEditor;
import com.google.gwt.event.dom.client.ClickEvent;
import com.google.gwt.event.dom.client.ClickHandler;
import com.google.gwt.event.logical.shared.ValueChangeEvent;
import com.google.gwt.event.logical.shared.ValueChangeHandler;
import com.google.gwt.event.shared.HandlerRegistration;
import com.google.gwt.i18n.client.HasDirection.Direction;
import com.google.gwt.i18n.shared.DirectionEstimator;
import com.google.gwt.i18n.shared.HasDirectionEstimator;
import com.google.gwt.safehtml.shared.SafeHtml;
import com.google.gwt.user.client.DOM;
import com.google.gwt.user.client.Element;
import com.google.gwt.user.client.Event;
import com.google.gwt.user.client.EventListener;

/**
 * A standard check box widget.
 * 
 * This class also serves as a base class for
 * {@link com.google.gwt.user.client.ui.RadioButton}.
 * 
 * 

* *

* *

*

Built-in Bidi Text Support

* 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. *

* *

CSS Style Rules

*
*
.gwt-CheckBox
*
the outer element
*
.gwt-CheckBox-disabled
*
applied when Checkbox is disabled
*
* *

*

Example

* {@example com.google.gwt.examples.CheckBoxExample} *

*/ public class CheckBox extends ButtonBase implements HasName, HasValue, HasWordWrap, HasDirectionalSafeHtml, HasDirectionEstimator, IsEditor> { public static final DirectionEstimator DEFAULT_DIRECTION_ESTIMATOR = DirectionalTextHelper.DEFAULT_DIRECTION_ESTIMATOR; final DirectionalTextHelper directionalTextHelper; InputElement inputElem; LabelElement labelElem; private LeafValueEditor editor; private boolean valueChangeHandlerInitialized; /** * Creates a check box with no label. */ public CheckBox() { this(DOM.createInputCheck()); setStyleName("gwt-CheckBox"); } /** * Creates a check box with the specified text label. * * @param label the check box's label */ public CheckBox(SafeHtml label) { this(label.asString(), true); } /** * Creates a check box with the specified text label. * * @param label the check box's label * @param dir the text's direction. Note that {@code DEFAULT} means direction * should be inherited from the widget's parent element. */ public CheckBox(SafeHtml label, Direction dir) { this(); setHTML(label, dir); } /** * Creates a check box with the specified text label. * * @param label the check box's label * @param directionEstimator A DirectionEstimator object used for automatic * direction adjustment. For convenience, * {@link #DEFAULT_DIRECTION_ESTIMATOR} can be used. */ public CheckBox(SafeHtml label, DirectionEstimator directionEstimator) { this(); setDirectionEstimator(directionEstimator); setHTML(label.asString()); } /** * Creates a check box with the specified text label. * * @param label the check box's label */ public CheckBox(String label) { this(); setText(label); } /** * Creates a check box with the specified text label. * * @param label the check box's label * @param dir the text's direction. Note that {@code DEFAULT} means direction * should be inherited from the widget's parent element. */ public CheckBox(String label, Direction dir) { this(); setText(label, dir); } /** * Creates a label with the specified text and a default direction estimator. * * @param label the check box's label * @param directionEstimator A DirectionEstimator object used for automatic * direction adjustment. For convenience, * {@link #DEFAULT_DIRECTION_ESTIMATOR} can be used. */ public CheckBox(String label, DirectionEstimator directionEstimator) { this(); setDirectionEstimator(directionEstimator); setText(label); } /** * Creates a check box with the specified text label. * * @param label the check box's label * @param asHTML true to treat the specified label as html */ public CheckBox(String label, boolean asHTML) { this(); if (asHTML) { setHTML(label); } else { setText(label); } } protected CheckBox(Element elem) { super(DOM.createSpan()); inputElem = InputElement.as(elem); labelElem = Document.get().createLabelElement(); getElement().appendChild(inputElem); getElement().appendChild(labelElem); String uid = DOM.createUniqueId(); inputElem.setPropertyString("id", uid); labelElem.setHtmlFor(uid); directionalTextHelper = new DirectionalTextHelper(labelElem, true); // Accessibility: setting tab index to be 0 by default, ensuring element // appears in tab sequence. FocusWidget's setElement method already // calls setTabIndex, which is overridden below. However, at the time // that this call is made, inputElem has not been created. So, we have // to call setTabIndex again, once inputElem has been created. setTabIndex(0); } public HandlerRegistration addValueChangeHandler( ValueChangeHandler handler) { // Is this the first value change handler? If so, time to add handlers if (!valueChangeHandlerInitialized) { ensureDomEventHandlers(); valueChangeHandlerInitialized = true; } return addHandler(handler, ValueChangeEvent.getType()); } public LeafValueEditor asEditor() { if (editor == null) { editor = TakesValueEditor.of(this); } return editor; } public DirectionEstimator getDirectionEstimator() { return directionalTextHelper.getDirectionEstimator(); } /** * Returns the value property of the input element that backs this widget. * This is the value that will be associated with the CheckBox name and * submitted to the server if a {@link FormPanel} that holds it is submitted * and the box is checked. *

* Don't confuse this with {@link #getValue}, which returns true or false if * the widget is checked. */ public String getFormValue() { return inputElem.getValue(); } @Override public String getHTML() { return directionalTextHelper.getTextOrHtml(true); } public String getName() { return inputElem.getName(); } @Override public int getTabIndex() { return inputElem.getTabIndex(); } @Override public String getText() { return directionalTextHelper.getTextOrHtml(false); } public Direction getTextDirection() { return directionalTextHelper.getTextDirection(); } /** * Determines whether this check box is currently checked. *

* Note that this does not return the value property of the checkbox * input element wrapped by this widget. For access to that property, see * {@link #getFormValue()} * * @return true if the check box is checked, false otherwise. * Will not return null */ public Boolean getValue() { if (isAttached()) { return inputElem.isChecked(); } else { return inputElem.isDefaultChecked(); } } public boolean getWordWrap() { return !getElement().getStyle().getProperty("whiteSpace").equals("nowrap"); } /** * Determines whether this check box is currently checked. * * @return true if the check box is checked * @deprecated Use {@link #getValue} instead */ @Deprecated public boolean isChecked() { // Funny comparison b/c getValue could in theory return null return getValue() == true; } @Override public boolean isEnabled() { return !inputElem.isDisabled(); } @Override public void setAccessKey(char key) { inputElem.setAccessKey("" + key); } /** * Checks or unchecks this check box. Does not fire {@link ValueChangeEvent}. * (If you want the event to fire, use {@link #setValue(Boolean, boolean)}) * * @param checked true to check the check box. * @deprecated Use {@link #setValue(Boolean)} instead */ @Deprecated public void setChecked(boolean checked) { setValue(checked); } /** * {@inheritDoc} *

* See note at {@link #setDirectionEstimator(DirectionEstimator)}. */ public void setDirectionEstimator(boolean enabled) { directionalTextHelper.setDirectionEstimator(enabled); } /** * {@inheritDoc} *

* Note: DirectionEstimator should be set before the label has any content; * it's highly recommended to set it using a constructor. Reason: if the * label already has non-empty content, this will update its direction * according to the new estimator's result. This may cause flicker, and thus * should be avoided. */ public void setDirectionEstimator(DirectionEstimator directionEstimator) { directionalTextHelper.setDirectionEstimator(directionEstimator); } @Override public void setEnabled(boolean enabled) { inputElem.setDisabled(!enabled); if (enabled) { removeStyleDependentName("disabled"); } else { addStyleDependentName("disabled"); } } @Override public void setFocus(boolean focused) { if (focused) { inputElem.focus(); } else { inputElem.blur(); } } /** * Set the value property on the input element that backs this widget. This is * the value that will be associated with the CheckBox's name and submitted to * the server if a {@link FormPanel} that holds it is submitted and the box is * checked. *

* Don't confuse this with {@link #setValue}, which actually checks and * unchecks the box. * * @param value */ public void setFormValue(String value) { inputElem.setAttribute("value", value); } public void setHTML(SafeHtml html, Direction dir) { directionalTextHelper.setTextOrHtml(html.asString(), dir, true); } @Override public void setHTML(String html) { directionalTextHelper.setTextOrHtml(html, true); } public void setName(String name) { inputElem.setName(name); } @Override public void setTabIndex(int index) { // Need to guard against call to setTabIndex before inputElem is // initialized. This happens because FocusWidget's (a superclass of // CheckBox) setElement method calls setTabIndex before inputElem is // initialized. See CheckBox's protected constructor for more information. if (inputElem != null) { inputElem.setTabIndex(index); } } @Override public void setText(String text) { directionalTextHelper.setTextOrHtml(text, false); } public void setText(String text, Direction dir) { directionalTextHelper.setTextOrHtml(text, dir, false); } /** * Checks or unchecks the check box. *

* Note that this does not set the value property of the checkbox * input element wrapped by this widget. For access to that property, see * {@link #setFormValue(String)} * * @param value true to check, false to uncheck; null value implies false */ public void setValue(Boolean value) { setValue(value, false); } /** * Checks or unchecks the check box, firing {@link ValueChangeEvent} if * appropriate. *

* Note that this does not set the value property of the checkbox * input element wrapped by this widget. For access to that property, see * {@link #setFormValue(String)} * * @param value true to check, false to uncheck; null value implies false * @param fireEvents If true, and value has changed, fire a * {@link ValueChangeEvent} */ public void setValue(Boolean value, boolean fireEvents) { if (value == null) { value = Boolean.FALSE; } Boolean oldValue = getValue(); inputElem.setChecked(value); inputElem.setDefaultChecked(value); if (value.equals(oldValue)) { return; } if (fireEvents) { ValueChangeEvent.fire(this, value); } } public void setWordWrap(boolean wrap) { getElement().getStyle().setProperty("whiteSpace", wrap ? "normal" : "nowrap"); } // Unlike other widgets the CheckBox sinks on its inputElement, not // its wrapper @Override public void sinkEvents(int eventBitsToAdd) { if (isOrWasAttached()) { Event.sinkEvents(inputElem, eventBitsToAdd | Event.getEventsSunk(inputElem)); } else { super.sinkEvents(eventBitsToAdd); } } protected void ensureDomEventHandlers() { addClickHandler(new ClickHandler() { public void onClick(ClickEvent event) { // Checkboxes always toggle their value, no need to compare // with old value. Radio buttons are not so lucky, see // overrides in RadioButton ValueChangeEvent.fire(CheckBox.this, getValue()); } }); } /** * Affected Elements: *

    *
  • -label = label next to checkbox.
  • *
* * @see UIObject#onEnsureDebugId(String) */ @Override protected void onEnsureDebugId(String baseID) { super.onEnsureDebugId(baseID); ensureDebugId(labelElem, baseID, "label"); ensureDebugId(inputElem, baseID, "input"); labelElem.setHtmlFor(inputElem.getId()); } /** * This method is called when a widget is attached to the browser's document. * onAttach needs special handling for the CheckBox case. Must still call * {@link Widget#onAttach()} to preserve the onAttach contract. */ @Override protected void onLoad() { setEventListener(inputElem, this); } /** * This method is called when a widget is detached from the browser's * document. Overridden because of IE bug that throws away checked state and * in order to clear the event listener off of the inputElem. */ @Override protected void onUnload() { // Clear out the inputElem's event listener (breaking the circular // reference between it and the widget). setEventListener(asOld(inputElem), null); setValue(getValue()); } /** * Replace the current input element with a new one. Preserves all state * except for the name property, for nasty reasons related to radio button * grouping. (See implementation of {@link RadioButton#setName}.) * * @param elem the new input element */ protected void replaceInputElement(Element elem) { InputElement newInputElem = InputElement.as(elem); // Collect information we need to set int tabIndex = getTabIndex(); boolean checked = getValue(); boolean enabled = isEnabled(); String formValue = getFormValue(); String uid = inputElem.getId(); String accessKey = inputElem.getAccessKey(); int sunkEvents = Event.getEventsSunk(inputElem); // Clear out the old input element setEventListener(asOld(inputElem), null); getElement().replaceChild(newInputElem, inputElem); // Sink events on the new element Event.sinkEvents(elem, Event.getEventsSunk(inputElem)); Event.sinkEvents(inputElem, 0); inputElem = newInputElem; // Setup the new element Event.sinkEvents(inputElem, sunkEvents); inputElem.setId(uid); if (!"".equals(accessKey)) { inputElem.setAccessKey(accessKey); } setTabIndex(tabIndex); setValue(checked); setEnabled(enabled); setFormValue(formValue); // Set the event listener if (isAttached()) { setEventListener(asOld(inputElem), this); } } private Element asOld(com.google.gwt.dom.client.Element elem) { Element oldSchool = elem.cast(); return oldSchool; } private void setEventListener(com.google.gwt.dom.client.Element e, EventListener listener) { DOM.setEventListener(asOld(e), listener); } }




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