org.opendatakit.common.web.client.UIEnabledActionCell.java Source code

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Here is the source code for org.opendatakit.common.web.client.UIEnabledActionCell.java

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/*
 * Copyright 2010 Google Inc.
 * Copyright (C) 2011 University of Washington
 *
 * 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 org.opendatakit.common.web.client;

import com.google.gwt.cell.client.AbstractCell;
import com.google.gwt.cell.client.ValueUpdater;
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.safehtml.shared.SafeHtml;
import com.google.gwt.safehtml.shared.SafeHtmlBuilder;
import com.google.gwt.safehtml.shared.SafeHtmlUtils;

/**
 * Implements a button that can be made not visible, enabled or disabled.
 * 
 * @author mitchellsundt@gmail.com
 * 
 * @param <T>
 */
public class UIEnabledActionCell<T> extends AbstractCell<T> {

    /**
     * The delegate that will handle events from the cell.
     * 
     * @param <T>
     *          the type that this delegate acts on
     */
    public static interface Delegate<C> {
        /**
         * Perform the desired action on the given object.
         * 
         * @param object
         *          the object to be acted upon
         */
        void execute(C object);
    }

    @Override
    public void onBrowserEvent(Context context, Element parent, T value, NativeEvent event,
            ValueUpdater<T> valueUpdater) {
        super.onBrowserEvent(context, parent, value, event, valueUpdater);
        if ("click".equals(event.getType())) {
            EventTarget eventTarget = event.getEventTarget();
            if (!Element.is(eventTarget)) {
                return;
            }
            if (parent.getFirstChildElement().isOrHasChild(Element.as(eventTarget))) {
                // Ignore clicks that occur outside of the main element.
                onEnterKeyDown(context, parent, value, event, valueUpdater);
            }
        }
    }

    @Override
    protected void onEnterKeyDown(Context context, Element parent, T value, NativeEvent event,
            ValueUpdater<T> valueUpdater) {
        if (isEnabledPredicate == null || isEnabledPredicate.isEnabled(value)) {
            delegate.execute(value);
        }
    }

    @Override
    public void render(Context context, T object, SafeHtmlBuilder sb) {
        if (isVisiblePredicate == null || isVisiblePredicate.isVisible(object)) {
            if (isEnabledPredicate == null || isEnabledPredicate.isEnabled(object)) {
                sb.append(htmlEnabled);
            } else {
                sb.append(htmlDisabled);
            }
        }
    }

    private final Delegate<T> delegate;
    private final SafeHtml htmlEnabled;
    private final SafeHtml htmlDisabled;
    private final UIEnabledPredicate<T> isEnabledPredicate;
    private final UIVisiblePredicate<T> isVisiblePredicate;

    public UIEnabledActionCell(String text, UIEnabledPredicate<T> isEnabledPredicate,
            UIEnabledActionCell.Delegate<T> delegate) {
        this(SafeHtmlUtils.fromString(text), null, isEnabledPredicate, delegate);
    }

    public UIEnabledActionCell(String text, UIVisiblePredicate<T> isVisiblePredicate,
            UIEnabledActionCell.Delegate<T> delegate) {
        this(SafeHtmlUtils.fromString(text), isVisiblePredicate, null, delegate);
    }

    public UIEnabledActionCell(String text, UIVisiblePredicate<T> isVisiblePredicate,
            UIEnabledPredicate<T> isEnabledPredicate, UIEnabledActionCell.Delegate<T> delegate) {
        this(SafeHtmlUtils.fromString(text), isVisiblePredicate, isEnabledPredicate, delegate);
    }

    public UIEnabledActionCell(SafeHtml text, UIVisiblePredicate<T> isVisiblePredicate,
            UIEnabledPredicate<T> isEnabledPredicate, UIEnabledActionCell.Delegate<T> delegate) {
        super("click", "keydown");
        this.isEnabledPredicate = isEnabledPredicate;
        this.isVisiblePredicate = isVisiblePredicate;
        this.delegate = delegate;
        htmlEnabled = new SafeHtmlBuilder()
                .appendHtmlConstant("<button class=\"gwt-Button\" type=\"button\" tabindex=\"-1\">").append(text)
                .appendHtmlConstant("</button>").toSafeHtml();
        htmlDisabled = new SafeHtmlBuilder()
                .appendHtmlConstant("<button class=\"gwt-Button\" type=\"button\" tabindex=\"-1\" disabled>")
                .append(text).appendHtmlConstant("</button>").toSafeHtml();
    }
}