samples/RandomMusicPlayer/src/com/example/android/musicplayer/RemoteControlHelper.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.musicplayer;

import android.media.AudioManager;
import android.util.Log;

import java.lang.reflect.Method;

/**
 * Contains methods to handle registering/unregistering remote control clients.  These methods only
 * run on ICS devices.  On previous devices, all methods are no-ops.
 */
@SuppressWarnings({"unchecked", "rawtypes"})
public class RemoteControlHelper {
    private static final String TAG = "RemoteControlHelper";

    private static boolean sHasRemoteControlAPIs = false;

    private static Method sRegisterRemoteControlClientMethod;
    private static Method sUnregisterRemoteControlClientMethod;

    static {
        try {
            ClassLoader classLoader = RemoteControlHelper.class.getClassLoader();
            Class sRemoteControlClientClass =
                    RemoteControlClientCompat.getActualRemoteControlClientClass(classLoader);
            sRegisterRemoteControlClientMethod = AudioManager.class.getMethod(
                    "registerRemoteControlClient", new Class[]{sRemoteControlClientClass});
            sUnregisterRemoteControlClientMethod = AudioManager.class.getMethod(
                    "unregisterRemoteControlClient", new Class[]{sRemoteControlClientClass});
            sHasRemoteControlAPIs = true;
        } catch (ClassNotFoundException e) {
            // Silently fail when running on an OS before ICS.
        } catch (NoSuchMethodException e) {
            // Silently fail when running on an OS before ICS.
        } catch (IllegalArgumentException e) {
            // Silently fail when running on an OS before ICS.
        } catch (SecurityException e) {
            // Silently fail when running on an OS before ICS.
        }
    }

    public static void registerRemoteControlClient(AudioManager audioManager,
            RemoteControlClientCompat remoteControlClient) {
        if (!sHasRemoteControlAPIs) {
            return;
        }

        try {
            sRegisterRemoteControlClientMethod.invoke(audioManager,
                    remoteControlClient.getActualRemoteControlClientObject());
        } catch (Exception e) {
            Log.e(TAG, e.getMessage(), e);
        }
    }


    public static void unregisterRemoteControlClient(AudioManager audioManager,
            RemoteControlClientCompat remoteControlClient) {
        if (!sHasRemoteControlAPIs) {
            return;
        }

        try {
            sUnregisterRemoteControlClientMethod.invoke(audioManager,
                    remoteControlClient.getActualRemoteControlClientObject());
        } catch (Exception e) {
            Log.e(TAG, e.getMessage(), e);
        }
    }
}