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/*
 * 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.cell.client;

import static com.google.gwt.dom.client.BrowserEvents.CLICK;
import static com.google.gwt.dom.client.BrowserEvents.KEYDOWN;
import static com.google.gwt.dom.client.BrowserEvents.MOUSEDOWN;

import com.google.gwt.core.client.GWT;
import com.google.gwt.dom.client.BrowserEvents;
import com.google.gwt.dom.client.Element;
import com.google.gwt.dom.client.NativeEvent;
import com.google.gwt.dom.client.Style.Unit;
import com.google.gwt.event.shared.HandlerRegistration;
import com.google.gwt.i18n.client.LocaleInfo;
import com.google.gwt.resources.client.ClientBundle;
import com.google.gwt.resources.client.CommonResources;
import com.google.gwt.resources.client.CssResource;
import com.google.gwt.resources.client.CssResource.ImportedWithPrefix;
import com.google.gwt.resources.client.ImageResource;
import com.google.gwt.resources.client.ImageResource.ImageOptions;
import com.google.gwt.resources.client.ImageResource.RepeatStyle;
import com.google.gwt.safecss.shared.SafeStyles;
import com.google.gwt.safecss.shared.SafeStylesBuilder;
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.safehtml.shared.SafeHtmlUtils;
import com.google.gwt.text.shared.SafeHtmlRenderer;
import com.google.gwt.user.client.Event;
import com.google.gwt.user.client.Event.NativePreviewEvent;
import com.google.gwt.user.client.Event.NativePreviewHandler;
import com.google.gwt.user.client.ui.AbstractImagePrototype;
import com.google.gwt.user.client.ui.HasEnabled;

/**
 * Base class for button Cells.
 * 
 * @param  the type that this Cell represents
 */
public class ButtonCellBase extends AbstractCell implements IsCollapsible, HasEnabled {

  /**
   * The appearance used to render this Cell.
   * 
   * @param  the type that this Cell represents
   */
  public interface Appearance {

    /**
     * Called when the user pushes the button down.
     * 
     * @param parent the parent Element
     */
    void onPush(Element parent);

    /**
     * Called when the user releases the button from being pushed.
     * 
     * @param parent the parent Element
     */
    void onUnpush(Element parent);

    /**
     * Render the button and its contents.
     * 
     * @param cell the cell that is being rendered
     * @param context the {@link Context} of the cell
     * @param value the value that generated the content
     * @param sb the {@link SafeHtmlBuilder} to render into
     */
    void render(ButtonCellBase cell, Context context, C value, SafeHtmlBuilder sb);

    /**
     * Explicitly focus/unfocus this cell.
     * 
     * @param parent the parent element
     * @param focused whether this cell should take focus or release it
     */
    void setFocus(Element parent, boolean focused);
  }

  /**
   * The decoration applied to the button.
   * 
   * 
*
DEFAULT
*
A general button used in any context.
*
PRIMARY
*
A primary button that stands out against other buttons.
*
NEGATIVE
*
A button that results in a negative action, such as delete or cancel
*
*/ public static enum Decoration { DEFAULT, PRIMARY, NEGATIVE; } /** * The default implementation of the {@link ButtonCellBase.Appearance}. * * @param the type that this Cell represents */ public static class DefaultAppearance implements Appearance { /** * The resources used by this appearance. */ public interface Resources extends ClientBundle { /** * The background image applied to the button. */ @ImageOptions(repeatStyle = RepeatStyle.Horizontal, flipRtl = true) ImageResource buttonCellBaseBackground(); @Source(Style.DEFAULT_CSS) Style buttonCellBaseStyle(); } /** * The Styles used by this appearance. */ @ImportedWithPrefix("gwt-ButtonCellBase") public interface Style extends CssResource { String DEFAULT_CSS = "com/google/gwt/cell/client/ButtonCellBase.css"; /** * Applied to the button. */ String buttonCellBase(); /** * Applied to the button when it has a collapsed left side. */ String buttonCellBaseCollapseLeft(); /** * Applied to the button when it has a collapsed right side. */ String buttonCellBaseCollapseRight(); /** * Applied to default buttons. */ String buttonCellBaseDefault(); /** * Applied to negative buttons. */ String buttonCellBaseNegative(); /** * Applied to primary buttons. */ String buttonCellBasePrimary(); /** * Applied to the button when being pushed. */ String buttonCellBasePushing(); } /** * The templates used by this appearance. */ interface Template extends SafeHtmlTemplates { /** * Positions the icon next to the text. * * NOTE: zoom:0 is a workaround for an IE7 bug where the button contents * wrap even when they do not need to. */ @SafeHtmlTemplates.Template("
{2}{3}
") SafeHtml iconContentLayout( String classes, SafeStyles styles, SafeHtml icon, SafeHtml cellContents); /** * The wrapper around the icon that aligns it vertically with the text. */ @SafeHtmlTemplates.Template("
" + "{1}
") SafeHtml iconWrapper(SafeStyles styles, SafeHtml image); } private static final int DEFAULT_ICON_PADDING = 3; private static Resources defaultResources; private static Template template; private static Resources getDefaultResources() { if (defaultResources == null) { defaultResources = GWT.create(Resources.class); } return defaultResources; } private SafeHtml iconSafeHtml = SafeHtmlUtils.EMPTY_SAFE_HTML; private ImageResource lastIcon; private final SafeHtmlRenderer renderer; private final Style style; /** * Construct a new {@link ButtonCellBase.DefaultAppearance} using the default styles. * * @param renderer the {@link SafeHtmlRenderer} used to render the contents */ public DefaultAppearance(SafeHtmlRenderer renderer) { this(renderer, getDefaultResources()); } /** * Construct a new {@link ButtonCellBase.DefaultAppearance} using the specified resources. * * @param renderer the {@link SafeHtmlRenderer} used to render the contents * @param resources the resources and styles to apply to the button */ public DefaultAppearance(SafeHtmlRenderer renderer, Resources resources) { this.renderer = renderer; this.style = resources.buttonCellBaseStyle(); this.style.ensureInjected(); if (template == null) { template = GWT.create(Template.class); } } /** * Return the {@link SafeHtmlRenderer} used by this Appearance to render the * contents of the button. * * @return a {@link SafeHtmlRenderer} instance */ public SafeHtmlRenderer getRenderer() { return renderer; } @Override public void onPush(Element parent) { parent.getFirstChildElement().addClassName(style.buttonCellBasePushing()); } @Override public void onUnpush(Element parent) { parent.getFirstChildElement().removeClassName(style.buttonCellBasePushing()); } @Override public void render(ButtonCellBase cell, Context context, C value, SafeHtmlBuilder sb) { // Determine the classes from the state of the button. SafeHtmlBuilder classes = new SafeHtmlBuilder(); classes.appendEscaped(style.buttonCellBase()); Decoration decoration = cell.getDecoration(); if (decoration == Decoration.PRIMARY) { classes.appendEscaped(" " + style.buttonCellBasePrimary()); } else if (decoration == Decoration.NEGATIVE) { classes.appendEscaped(" " + style.buttonCellBaseNegative()); } else { classes.appendEscaped(" " + style.buttonCellBaseDefault()); } if (cell.isCollapseLeft()) { classes.appendEscaped(" " + style.buttonCellBaseCollapseLeft()); } if (cell.isCollapseRight()) { classes.appendEscaped(" " + style.buttonCellBaseCollapseRight()); } // Update the cached HTML string used for the icon if the icon changes. ImageResource icon = cell.getIcon(); if (icon != lastIcon) { if (icon == null) { iconSafeHtml = SafeHtmlUtils.EMPTY_SAFE_HTML; } else { AbstractImagePrototype proto = AbstractImagePrototype.create(icon); SafeHtml iconOnly = SafeHtmlUtils.fromTrustedString(proto.getHTML()); int halfHeight = (int) Math.round(icon.getHeight() / 2.0); SafeStylesBuilder styles = new SafeStylesBuilder(); styles.marginTop(-halfHeight, Unit.PX); if (LocaleInfo.getCurrentLocale().isRTL()) { styles.right(0, Unit.PX); } else { styles.left(0, Unit.PX); } iconSafeHtml = template.iconWrapper(styles.toSafeStyles(), iconOnly); } } // Figure out the attributes. char accessKey = cell.getAccessKey(); StringBuilder attributes = new StringBuilder(); if (!cell.isEnabled()) { attributes.append("disabled=disabled "); } if (accessKey != 0) { attributes.append("accessKey=\"").append(SafeHtmlUtils.htmlEscape("" + accessKey)); attributes.append("\" "); } // Create the button. SafeStylesBuilder styles = new SafeStylesBuilder(); int iconWidth = (icon == null) ? 0 : icon.getWidth(); int iconPadding = iconWidth + DEFAULT_ICON_PADDING; if (LocaleInfo.getCurrentLocale().isRTL()) { styles.paddingRight(iconPadding, Unit.PX); } else { styles.paddingLeft(iconPadding, Unit.PX); } SafeHtml safeValue = renderer.render(value); SafeHtml content = template.iconContentLayout( CommonResources.getInlineBlockStyle(), styles.toSafeStyles(), iconSafeHtml, safeValue); int tabIndex = cell.getTabIndex(); StringBuilder openTag = new StringBuilder(); openTag.append(""); } @Override public void setFocus(Element parent, boolean focused) { Element focusable = parent.getFirstChildElement().cast(); if (focused) { focusable.focus(); } else { focusable.blur(); } } } /** * The {@link NativePreviewHandler} used to unpush a button onmouseup, even if * the event doesn't occur over the button. */ private class UnpushHandler implements NativePreviewHandler { private final Element parent; private final HandlerRegistration reg; public UnpushHandler(Element parent) { this.parent = parent; this.reg = Event.addNativePreviewHandler(this); } @Override public void onPreviewNativeEvent(NativePreviewEvent event) { if (BrowserEvents.MOUSEUP.equals(event.getNativeEvent().getType())) { // Unregister self. reg.removeHandler(); // Unpush the element. appearance.onUnpush(parent); } } } private char accessKey; private final Appearance appearance; private Decoration decoration = Decoration.DEFAULT; private ImageResource icon; private boolean isCollapsedLeft; private boolean isCollapsedRight; private boolean isEnabled = true; /** * The tab index applied to the buttons. If the button is used in a list of * table, a tab index of -1 should be used so it doesn't interrupt the tab * sequence. */ private int tabIndex = -1; /** * Construct a new {@link ButtonCellBase} using the specified * {@link Appearance} to render the contents. * * @param appearance the appearance of the cell */ public ButtonCellBase(Appearance appearance) { super(CLICK, KEYDOWN, MOUSEDOWN); this.appearance = appearance; } /** * Get the access key. * * @return the access key, or 0 if one is not defined */ public char getAccessKey() { return accessKey; } /** * Get the decoration style of the button. */ public Decoration getDecoration() { return decoration; } /** * Get the icon displayed next to the button text. * * @return the icon resource */ public ImageResource getIcon() { return icon; } /** * Return the tab index that is given to all rendered cells. * * @return the tab index */ public int getTabIndex() { return tabIndex; } @Override public boolean isCollapseLeft() { return this.isCollapsedLeft; } @Override public boolean isCollapseRight() { return this.isCollapsedRight; } @Override public boolean isEnabled() { return isEnabled; } @Override public void onBrowserEvent(Context context, Element parent, C value, NativeEvent event, ValueUpdater valueUpdater) { // Ignore all events if disabled. if (!isEnabled()) { return; } // Let AbstractCell handle the enter key. super.onBrowserEvent(context, parent, value, event, valueUpdater); // Ignore events that occur outside of the button element. Element target = event.getEventTarget().cast(); if (!parent.getFirstChildElement().isOrHasChild(target)) { return; } String eventType = event.getType(); if (CLICK.equals(eventType)) { // Click the button. onEnterKeyDown(context, parent, value, event, valueUpdater); } else if (MOUSEDOWN.equals(eventType)) { // Push. appearance.onPush(parent); /* * Add a preview handler to unpush the button onmouseup or onblur, even if * the event doesn't occur over the button. */ new UnpushHandler(parent); // We will be handling all user visual feedback manually. Prevent browser // doing default handling (i.e. double-click highlights button text). event.preventDefault(); } } @Override public void render(Context context, C value, SafeHtmlBuilder sb) { appearance.render(this, context, value, sb); } /** * Sets the cell's 'access key'. This key is used (in conjunction with a * browser-specific modifier key) to automatically focus the cell. * *

* The change takes effect the next time the Cell is rendered. * * @param key the cell's access key */ public void setAccessKey(char key) { this.accessKey = key; } /** * {@inheritDoc} * *

* The change takes effect the next time the Cell is rendered. */ @Override public void setCollapseLeft(boolean isCollapsed) { this.isCollapsedLeft = isCollapsed; } /** * {@inheritDoc} * *

* The change takes effect the next time the Cell is rendered. */ @Override public void setCollapseRight(boolean isCollapsed) { this.isCollapsedRight = isCollapsed; } /** * Set the {@link Decoration} of the button. * *

* This change takes effect the next time the cell is rendered. * * @param decoration the button decoration */ public void setDecoration(Decoration decoration) { this.decoration = decoration; } /** * {@inheritDoc} * *

* The change takes effect the next time the Cell is rendered. */ @Override public void setEnabled(boolean isEnabled) { this.isEnabled = isEnabled; } /** * Explicitly focus/unfocus this cell. Only one UI component can have focus at * a time, and the component that does will receive all keyboard events. * * @param parent the parent element * @param focused whether this cell should take focus or release it */ public void setFocus(Element parent, boolean focused) { appearance.setFocus(parent, focused); } /** * Set the icon to display next to the button text. * * @param icon the icon resource, or null not to show an icon */ public void setIcon(ImageResource icon) { this.icon = icon; } /** * Set the tab index to apply to the button. By default, the tab index is set * to -1 so that the button does not interrupt the tab chain when in a table * or list. The change takes effect the next time the Cell is rendered. * * @param tabIndex the tab index */ public void setTabIndex(int tabIndex) { this.tabIndex = tabIndex; } @Override protected void onEnterKeyDown(Context context, Element parent, C value, NativeEvent event, ValueUpdater valueUpdater) { if (valueUpdater != null) { valueUpdater.update(value); } } }





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