samples/training/multiscreen/newsreader/src/com/example/android/newsreader/CompatActionBarNavHandler.java

/*
 * Copyright (C) 2011 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.example.android.newsreader;

import android.app.ActionBar.OnNavigationListener;
import android.app.ActionBar.Tab;
import android.app.ActionBar.TabListener;
import android.app.FragmentTransaction;

/**
 * Adapter for action bar navigation events.
 *
 * This class implements an adapter that facilitates handling of action bar navigation events.
 * An instance of this class must be installed as a TabListener or OnNavigationListener on an
 * Action Bar, and it will relay the navigation events to a configured listener
 * (a {@link CompatActionBarNavListener}).
 *
 * This class should only be instanced and used on Android platforms that support the Action Bar,
 * that is, SDK level 11 and above.
 */
public class CompatActionBarNavHandler implements TabListener, OnNavigationListener {
    // The listener that we notify of navigation events
    CompatActionBarNavListener mNavListener;

    /**
     * Constructs an instance with the given listener.
     *
     * @param listener the listener to notify when a navigation event occurs.
     */
    public CompatActionBarNavHandler(CompatActionBarNavListener listener) {
        mNavListener = listener;
    }

    /**
     * Called by framework when a tab is selected.
     *
     * This will cause a navigation event to be delivered to the configured listener.
     */
    @Override
    public void onTabSelected(Tab tab, FragmentTransaction ft) {
        // TODO Auto-generated method stub
        mNavListener.onCategorySelected(tab.getPosition());
    }

    /**
     * Called by framework when a item on the navigation menu is selected.
     *
     * This will cause a navigation event to be delivered to the configured listener.
     */
    @Override
    public boolean onNavigationItemSelected(int itemPosition, long itemId) {
        mNavListener.onCategorySelected(itemPosition);
        return true;
    }


    /**
     * Called by framework when a tab is re-selected. That is, it was already selected and is
     * tapped on again. This is not used in our app.
     */
    @Override
    public void onTabReselected(Tab tab, FragmentTransaction ft) {
        // we don't care
    }

    /**
     * Called by framework when a tab is unselected. Not used in our app.
     */
    @Override
    public void onTabUnselected(Tab tab, FragmentTransaction ft) {
        // we don't care
    }

}