Question

Suppose I am creating an Android application that’s like an SMS app. The requirements are as follows:

1. The user can receive multiple notifications, each one having a dynamic ID of type int.
2. When a notification is selected, it loads an activity which displays a corresponding message (the SMS).
3. The single notification that was selected should be automatically dismissed.

My idea for how to handle this was to use putExtra to add the integer ID to the intent, which would then be accessible from the intent within the activity it loads, which would then dismiss the notification that called it.

For my test case, here are the specs:

1. Notifications will eventually be
   generated from a service, for now
   they are being spawned when the test
   user presses a button.
2. When a notification is selected, the
   called activity toasts the message,
   then attempts to dismiss the
   notification. (For the sake of
   visibility)

Here are my problems:

1. When the first notification is
   selected, it is correct. The
   notification is dismissed.
2. When each successive notification is
   selected, the first notification’s
   ID is shown, and nothing is
   dismissed.
3. I am a Java novice, more accustomed
   to scripting languages (such as
   Perl, PHP, etc) 🙂

Here is my source:

<?xml version="1.0" encoding="UTF-8"?>
<LinearLayout xmlns:android = "http://schemas.android.com/apk/res/android"
    android:orientation = "vertical"
    android:layout_width = "fill_parent"
    android:layout_height = "fill_parent"
>
    <Button
        android:id="@+id/create_notification"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:padding="10dp"
        android:text = "Create new notification"
    />

package org.test.notifydemo;

import android.app.Activity;
import android.app.Notification;
import android.app.NotificationManager;
import android.app.PendingIntent;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;
import java.util.Random;

public class aRunNotificationDemo extends Activity
{
    private NotificationManager mNotificationManager;

    @Override
    public void onCreate( Bundle icicle )
    {
        super.onCreate( icicle );
        setContentView( R.layout.run_notify_demo );

        mNotificationManager = (NotificationManager) getSystemService( aRunNotificationDemo.NOTIFICATION_SERVICE );

        int close_notify_id = getIntent().getIntExtra( "notification_id", 0 );
        if ( close_notify_id != 0 )
        {
            Toast.makeText( aRunNotificationDemo.this, "Dimissing this notification: " + Integer.toString(close_notify_id), Toast.LENGTH_SHORT ).show();
            mNotificationManager.cancel( close_notify_id );
        }

        findViewById( R.id.create_notification ).setOnClickListener( new MyButtonListener() );
    }

    private class MyButtonListener implements Button.OnClickListener
    {
        public void onClick( View my_view )
        {
            Random randGen = new Random();
            int notify_id = randGen.nextInt();

            int icon = R.drawable.icon_notification_01;
            CharSequence tickerText = Integer.toString(notify_id) + " New SMS!";
            long when = System.currentTimeMillis();

            Notification my_notification = new Notification(icon, tickerText, when);

            Context context = getApplicationContext();
            CharSequence contentTitle = Integer.toString(notify_id) + " New SMS Available!";
            CharSequence contentText = Integer.toString(notify_id) + " There is a new SMS available.";
            Intent notificationIntent = new Intent( aRunNotificationDemo.this, aRunNotificationDemo.class );

            notificationIntent.putExtra( "notification_id", notify_id );

            PendingIntent contentIntent = PendingIntent.getActivity( aRunNotificationDemo.this, 0, notificationIntent, 0 );

            my_notification.setLatestEventInfo( context, contentTitle, contentText, contentIntent );

            mNotificationManager.notify( notify_id, my_notification );
        }
    }

}

Answer 1

When activity is once created its onCreate() method is called. Next time it is displayed the method is not necessarily called. Try moving code which removes the notification to onResume() method. Get familiar with Activity life cycle.

And by the way it is easier than you think:

http://developer.android.com/reference/android/app/Notification.html#FLAG_AUTO_CANCEL

my_notification.flags |= Notification.FLAG_AUTO_CANCEL;

Put the code above when creating a Notification.