code: /*
   * Copyright 2015 Google Inc. All rights reserved.
   *
   * 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.physical_web.physicalweb;
  
  import android.app.Service;
  import android.content.BroadcastReceiver;
  import android.content.Context;
  import android.content.Intent;
  import android.content.IntentFilter;
  import android.os.IBinder;
  
  /**
   * This is a service registers a broadcast receiver to listen for screen on/off events.
   * It is a very unfortunate service that must exist because we can't register for screen on/off
   * in the manifest.
   */
  
  public class ScreenListenerService extends Service {
    private BroadcastReceiver mScreenStateBroadcastReceiver = new BroadcastReceiver() {
      @Override
      public void onReceive(Context context, Intent intent) {
        Intent discoveryIntent = new Intent(context, UrlDeviceDiscoveryService.class);
        if (intent.getAction().equals(Intent.ACTION_SCREEN_ON)) {
          context.startService(discoveryIntent);
        } else if (intent.getAction().equals(Intent.ACTION_SCREEN_OFF)) {
          context.stopService(discoveryIntent);
        }
      }
    };
  
    @Override
    public void onCreate() {
      super.onCreate();
      IntentFilter intentFilter = new IntentFilter();
      intentFilter.addAction(Intent.ACTION_SCREEN_ON);
      intentFilter.addAction(Intent.ACTION_SCREEN_OFF);
      registerReceiver(mScreenStateBroadcastReceiver, intentFilter);
    }
  
    @Override
    public void onDestroy() {
      unregisterReceiver(mScreenStateBroadcastReceiver);
      super.onDestroy();
    }
  
    @Override
    public IBinder onBind(Intent intent) {
      // Nothing should bind to this service
      return null;
    }
  }
  