Determine if headphones are plugged in through AppWidgetProvider, pause music when unplugged

Question

There are a million and five questions on SO about this, but I've tried sorting through them all, and can not get it working. I know that AppWidgetProvider just extends BroadcastReceiver so I think I can just do everything within my AppWidgetProvider. I've read that the intent filter ACTION_HEADSET_PLUG is Intent.FLAG_RECEIVER_REGISTERED_ONLY and tried following this: Detecting whether a headset is plugged into an Android device or not. to set my filter in code, but it was pretty mish-mash and I couldn't wrap my head around it.

I've toasted out intent.getAction() in my onReceive method and when I plug or unplug my headphones, nothing gets shown. When I press buttons though, I see the int constant associated with them. I'm assuming this is because it's being blocked by the registered only thing.

I also read about some sticky-something-or-other and forked around with that for a while, all to no avail.

here is my AppWidgetManager:

package com.example.musicplayerforburrito;

import android.app.PendingIntent;
import android.appwidget.AppWidgetManager;
import android.appwidget.AppWidgetProvider;
import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.media.MediaPlayer;
import android.widget.RemoteViews;
import android.widget.Toast;




public class MyWidgetProvider extends AppWidgetProvider {

    public static String WIDGET_PLAY_BUTTON = "android.appwidget.action.PLAY_PAUSE_WIDGETS";
    public static String NEXT_BUTTON = "android.appwidget.action.NEXT_WIDGETS";
    public static String PREVIOUS_BUTTON = "android.appwidget.action.PREVIOUS_WIDGETS";
    public static String RELOAD_BUTTON = "android.appwidget.action.RELOAD_WIDGETS";


    static MusicPlayerClass mpc;
    static String CurrentlyPlayingSong = "";
    static Context cont;

  @Override
  public void onUpdate(Context context, AppWidgetManager appWidgetManager, int[] appWidgetIds) {


      mpc = new MusicPlayerClass(context);
      RemoteViews remoteViews = new RemoteViews(context.getPackageName(), R.layout.widget_layout);
      ComponentName watchWidget = new ComponentName(context, MyWidgetProvider.class);

      remoteViews.setOnClickPendingIntent(R.id.playpausewidget, getPendingSelfIntent(context, WIDGET_PLAY_BUTTON));
      remoteViews.setOnClickPendingIntent(R.id.forwardwidget, getPendingSelfIntent(context, NEXT_BUTTON));
      remoteViews.setOnClickPendingIntent(R.id.backwidget, getPendingSelfIntent(context, PREVIOUS_BUTTON));
      remoteViews.setOnClickPendingIntent(R.id.reloadwidget, getPendingSelfIntent(context, RELOAD_BUTTON));
      appWidgetManager.updateAppWidget(watchWidget, remoteViews);
  }

  @Override
  public void onReceive(Context context, Intent intent) {
      // TODO Auto-generated method stub
      super.onReceive(context, intent);
      //if(intent.hasExtra("state"))
        //  Toast.makeText(context, "hi jimmy", 2000).show();
      Toast.makeText(context, intent.getAction(), 2000).show();

      try
      {
          String b = mpc.currentlyPlayingSong;
      }
      catch(Exception e)
      {
          mpc = new MusicPlayerClass(context);
      }
      AppWidgetManager appWidgetManager = AppWidgetManager.getInstance(context);
      RemoteViews remoteViews = new RemoteViews( context.getPackageName(), R.layout.widget_layout );
      ComponentName watchWidget = new ComponentName(context, MyWidgetProvider.class);
      cont = context;
      if (WIDGET_PLAY_BUTTON.equals(intent.getAction())) {

          if(!mpc.hasFolders)
          {
              mpc.Initialize();
              mpc.mp.setOnCompletionListener(new MediaPlayer.OnCompletionListener() 
                {           
                    public void onCompletion(MediaPlayer mp) 
                    {
                        mpc.songIndex++;
                        CurrentlyPlayingSong = mpc.StartSong();
                        UpdateTitle(cont);
                    }           
                });
          }
          if(mpc.isPlaying)
            {
                mpc.isPlaying = false;
                mpc.PauseMusic();
                remoteViews.setImageViewResource(R.id.playpausewidget, R.drawable.play);
            }
            else if(mpc.currentPosition != 0)
            {
                mpc.isPlaying = true;
                mpc.ResumeMusic();
                remoteViews.setImageViewResource(R.id.playpausewidget, R.drawable.pause);                   
            }
            else
            {
                remoteViews.setTextViewText(R.id.mp3filename, mpc.StartSong());
                remoteViews.setImageViewResource(R.id.playpausewidget, R.drawable.pause);
            } 

      }   
      else if (NEXT_BUTTON.equals(intent.getAction())) {
          mpc.songIndex++;
          remoteViews.setTextViewText(R.id.mp3filename, mpc.StartSong());
      }
      else if (PREVIOUS_BUTTON.equals(intent.getAction())) {
          mpc.songIndex--;
          remoteViews.setTextViewText(R.id.mp3filename, mpc.StartSong());
      }
      else if (RELOAD_BUTTON.equals(intent.getAction())) {
          mpc.Reload();
          mpc.mp.setOnCompletionListener(new MediaPlayer.OnCompletionListener() 
            {           
              public void onCompletion(MediaPlayer mp) 
              {
                mpc.songIndex++;
                CurrentlyPlayingSong = mpc.StartSong();
                UpdateTitle(cont);
              }           
          });
          remoteViews.setTextViewText(R.id.mp3filename, mpc.StartSong());
          remoteViews.setImageViewResource(R.id.playpausewidget, R.drawable.pause);
      }
      appWidgetManager.updateAppWidget(watchWidget, remoteViews);   
  }

 private void UpdateTitle(Context context)
 {
     AppWidgetManager appWidgetManager = AppWidgetManager.getInstance(context);
     RemoteViews remoteViews = new RemoteViews( context.getPackageName(), R.layout.widget_layout );
     ComponentName watchWidget = new ComponentName(context, MyWidgetProvider.class);
     remoteViews.setTextViewText(R.id.mp3filename, CurrentlyPlayingSong);
     appWidgetManager.updateAppWidget(watchWidget, remoteViews);    
 }


  protected PendingIntent getPendingSelfIntent(Context context, String action) {
      Intent intent = new Intent(context, getClass());
      intent.setAction(action);
      return PendingIntent.getBroadcast(context, 0, intent, 0);
  }
} 

here is my manifest:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.musicplayerforburrito"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="15"
        android:targetSdkVersion="16" />
    <uses-permission android:name="android.permission.READ_PHONE_STATE" /> 
    <uses-permission android:name="android.permission.MODIFY_AUDIO_SETTINGS" />
    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <receiver android:name="MyWidgetProvider" >
            <intent-filter >
                <action 
                    android:name="android.appwidget.action.APPWIDGET_UPDATE" />
                <action android:name="android.appwidget.action.PLAY_PAUSE_WIDGETS" />
                <action android:name="android.appwidget.action.NEXT_WIDGETS" />
                <action android:name="android.appwidget.action.PREVIOUS_WIDGETS" />
                <action android:name="android.appwidget.action.RELOAD_WIDGETS" />
                <action android:name="android.appwidget.action.ACTION_HEADSET_PLUG" />

            </intent-filter>
            <intent-filter>
                <action android:name="android.intent.action.ACTION_HEADSET_PLUG"/>
            </intent-filter>

            <meta-data
                android:name="android.appwidget.provider"
                android:resource="@xml/widget_info" />
        </receiver>
        <activity
            android:name="com.example.musicplayerforburrito.MusicPlayer"
            android:label="@string/app_name"
            android:screenOrientation="portrait" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

I've been fighting with this for literally hours which seems really stupid because it's not even that big of a "feature" to pause the music when the headphones are unplugged. Any guidance you can share would be greatly appreciated.

TIA

Answer 1

The answer at https://stackoverflow.com/a/9682818/1682419 quotes Dianne Hackborn (who's in the core Android team). You'll need a Service or Activity that stays running as long as you're interested in these broadcast messages, and it needs to call registerReceiver() to register for these messages.

Note 1: When you invent Intent actions, you're supposed to use your own package name, not android.intent.action, to avoid name conflicts.

Note 2: The widget provider's <intent-filter> should only list the public action android.appwidget.action.APPWIDGET_UPDATE. There's no benefit in including the private on-click actions and android.intent.action.ACTION_HEADSET_PLUG.