core/java/android/app/MediaRouteActionProvider.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 android.app;

import android.content.Context;
import android.media.MediaRouter;
import android.media.MediaRouter.RouteInfo;
import android.util.Log;
import android.view.ActionProvider;
import android.view.MenuItem;
import android.view.View;

public class MediaRouteActionProvider extends ActionProvider {
    private static final String TAG = "MediaRouteActionProvider";

    private Context mContext;
    private MediaRouter mRouter;
    private MenuItem mMenuItem;
    private MediaRouteButton mView;
    private int mRouteTypes;
    private final RouterCallback mRouterCallback = new RouterCallback();

    public MediaRouteActionProvider(Context context) {
        super(context);
        mContext = context;
        mRouter = MediaRouter.forApplication(context);

        // Start with live audio by default.
        // TODO Update this when new route types are added; segment by API level
        // when different route types were added.
        setRouteTypes(MediaRouter.ROUTE_TYPE_LIVE_AUDIO);
    }

    public void setRouteTypes(int types) {
        if (types == mRouteTypes) {
            // Already registered; nothing to do.
            return;
        }
        if (mRouteTypes != 0) {
            mRouter.removeCallback(mRouterCallback);
        }
        mRouteTypes = types;
        if (mView != null) {
            mView.setRouteTypes(mRouteTypes);
        }
        mRouter.addCallback(types, mRouterCallback);
    }

    @Override
    public View onCreateActionView() {
        throw new UnsupportedOperationException("Use onCreateActionView(MenuItem) instead.");
    }

    @Override
    public View onCreateActionView(MenuItem item) {
        if (mMenuItem != null || mView != null) {
            Log.e(TAG, "onCreateActionView: this ActionProvider is already associated " +
                    "with a menu item. Don't reuse MediaRouteActionProvider instances! " +
                    "Abandoning the old one...");
        }
        mMenuItem = item;
        mView = new MediaRouteButton(mContext);
        mMenuItem.setVisible(mRouter.getRouteCount() > 1);
        mView.setRouteTypes(mRouteTypes);
        return mView;
    }

    @Override
    public boolean onPerformDefaultAction() {
        // Show routing dialog
        return true;
    }

    private class RouterCallback extends MediaRouter.SimpleCallback {
        @Override
        public void onRouteAdded(MediaRouter router, RouteInfo info) {
            mMenuItem.setVisible(mRouter.getRouteCount() > 1);
        }

        @Override
        public void onRouteRemoved(MediaRouter router, RouteInfo info) {
            mMenuItem.setVisible(mRouter.getRouteCount() > 1);
        }
    }
}