src/plugins/snippets/src/com/motorola/studio/android/codesnippets/TooltipDisplayConfigContriutionItem.java

/*
* Copyright (C) 2012 The Android Open Source Project
*
* 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.motorola.studio.android.codesnippets;

import org.eclipse.core.runtime.preferences.ConfigurationScope;
import org.eclipse.core.runtime.preferences.IEclipsePreferences;
import org.eclipse.jface.action.ControlContribution;
import org.eclipse.jface.dialogs.IDialogSettings;
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.events.SelectionListener;
import org.eclipse.swt.layout.RowLayout;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;
import org.osgi.service.prefs.BackingStoreException;

import com.motorola.studio.android.codesnippets.i18n.AndroidSnippetsNLS;
import com.motorola.studio.android.common.log.StudioLogger;

/**
 * This {@link ControlContribution} adds the check box button which
 * shows or hides the tooltip of the snippet.
 * 
 * @see ControlContribution
 * @see {@link AndroidSnippetsStartup}
 *
 */
public class TooltipDisplayConfigContriutionItem extends ControlContribution
{
    /**
     * Listener which updates the status of whether or not to display
     * the tool tip.
     * 
     * @see SelectionListener
     * 
     */
    private final class TooltipSelectionListener implements SelectionListener
    {
        /** 
         * Here the state of the tooltip display button is persisted in
         * the {@link IDialogSettings}.
         * 
         * @see org.eclipse.swt.events.SelectionListener#widgetSelected(org.eclipse.swt.events.SelectionEvent)
         */
        public void widgetSelected(SelectionEvent e)
        {
            // action for when the check box is pressed.
            performButtonSelection();
        }

        /* (non-Javadoc)
         * @see org.eclipse.swt.events.SelectionListener#widgetDefaultSelected(org.eclipse.swt.events.SelectionEvent)
         */
        public void widgetDefaultSelected(SelectionEvent e)
        {
            // do nothing
        }
    }

    /**
     * Check box {@link Button} which shows or hides the tooltip.
     */
    private Button showToolTipButton = null;

    /**
     * {@link IDialogSettings} field for whether or not the tooltip
     * is to be displayed.
     */
    private static final String DIALOG_SETTINGS__IS_TOOLTIP_DISPLAYED = "IsTooltipDisplayed";

    /**
     * Constructor which initiates this {@link ControlContribution}.
     */
    public TooltipDisplayConfigContriutionItem()
    {
        super("com.motorola.studio.android.codesnippets.tooltipDisplayConfig"); //$NON-NLS-1$
    }

    /* (non-Javadoc)
     * @see org.eclipse.jface.action.ControlContribution#createControl(org.eclipse.swt.widgets.Composite)
     */
    @Override
    protected Control createControl(Composite parent)
    {
        // adjust layout in order to produce space to the left
        Composite mainComposite = new Composite(parent, SWT.NONE);
        RowLayout layout = new RowLayout(SWT.FILL);
        layout.center = true;
        layout.marginLeft = 10;
        mainComposite.setLayout(layout);

        // create the check box button
        showToolTipButton = new Button(mainComposite, SWT.CHECK);
        showToolTipButton
                .setText(AndroidSnippetsNLS.TooltipDisplayConfigContriutionItem_ShowPreview);
        showToolTipButton.addSelectionListener(new TooltipSelectionListener());

        // set the selection persisted
        IEclipsePreferences preferences = getEclipsePreferences();
        boolean isTooltipDisplayed =
                preferences.getBoolean(DIALOG_SETTINGS__IS_TOOLTIP_DISPLAYED, true);
        showToolTipButton.setSelection(isTooltipDisplayed);
        performButtonSelection();

        return mainComposite;
    }

    /**
     * Returns <code>true</code> in case the tool tip is to
     * be displayed, or <code>false</code> should it be hidden.
     * 
     * @return <code>true</code> in case the tool tip
     * is to be displayed, <code>false</code> otherwise.
     */
    public boolean isTooltipDisplayed()
    {
        return showToolTipButton.getSelection();
    }

    /**
     * Method called when the check box {@link Button} is called. It
     * persists the check box selection state in the {@link IDialogSettings}.
     */
    private void performButtonSelection()
    {
        // persist whether or not to show the tooltip
        IEclipsePreferences preferences = getEclipsePreferences();
        preferences.putBoolean(DIALOG_SETTINGS__IS_TOOLTIP_DISPLAYED,
                showToolTipButton.getSelection());
        try
        {
            preferences.flush();
        }
        catch (BackingStoreException bse)
        {
            StudioLogger.error(TooltipDisplayConfigContriutionItem.class.toString(),
                    "Preferences for snippets could not be saved.", bse); //$NON-NLS-1$
        }
    }

    /**
     * Get Eclipse´s preferences.
     * 
     * @return Return Eclipse´s preferences.
     */
    private IEclipsePreferences getEclipsePreferences()
    {
        return ConfigurationScope.INSTANCE.getNode(AndroidSnippetsStartup.SNIPPETS_VIEW_ID);
    }
}