How to send parameters from a notification-click to an activity?

Question

I can find a way to send parameters to my activity from my notification.

I have a service that creates a notification. When the user clicks on the notification I want to open my main activity with some special parameters. E.g an item id, so my activity can load and present a special item detail view. More specific, I'm downloading a file, and when the file is downloaded I want the notification to have an intent that when clicked it opens my activity in a special mode. I have tried to use putExtra on my intent, but cant seem to extract it, so I think I'm doing it wrong.

Code from my service that creates the Notification:

        // construct the Notification object.
     final Notification notif = new Notification(R.drawable.icon, tickerText, System.currentTimeMillis());


    final RemoteViews contentView = new RemoteViews(context.getPackageName(), R.layout.custom_notification_layout);
    contentView.setImageViewResource(R.id.image, R.drawable.icon);
    contentView.setTextViewText(R.id.text, tickerText);
    contentView.setProgressBar(R.id.progress,100,0, false);
    notif.contentView = contentView;        

    Intent notificationIntent = new Intent(context, Main.class);
    notificationIntent.putExtra("item_id", "1001"); // <-- HERE I PUT THE EXTRA VALUE
    PendingIntent contentIntent = PendingIntent.getActivity(context, 0, notificationIntent, 0);
    notif.contentIntent = contentIntent;

    nm.notify(id, notif);

Code from my Activity that tries to fetch the extra parameter from the notification:

 public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    setContentView(R.layout.main);


    Bundle extras = getIntent().getExtras();
    if(extras != null){
        Log.i( "dd","Extra:" + extras.getString("item_id") );
    }

The extras is always null and I never gets anything into my log.

Btw... the onCreate is only run when my activity starts, if my activity is already started I also want to collect the extras and present my activity according to the item_id I receive.

Any ideas?

Answer 1

Take a look at this guide (creating a notification) and to samples ApiDemos "StatusBarNotifications" and "NotificationDisplay".

For managing if the activity is already running you have two ways:

1. Add FLAG_ACTIVITY_SINGLE_TOP flag to the Intent when launching the activity, and then in the activity class implement onNewIntent(Intent intent) event handler, that way you can access the new intent that was called for the activity (which is not the same as just calling getIntent(), this will always return the first Intent that launched your activity.

2. Same as number one, but instead of adding a flag to the Intent you must add "singleTop" in your activity AndroidManifest.xml.

If you use intent extras, remeber to call PendingIntent.getActivity() with the flag PendingIntent.FLAG_UPDATE_CURRENT, otherwise the same extras will be reused for every notification.