Android - Auto update app icon badge counter from content provider?

Question

I have used this solution to add a badge counter to my app icon. I am using the counter to show how many items there are in the app's queue_table that are waiting to be sent to the server.

First of all, I have create a MyBootReceiver class that updates the badge count when the device boots. This part works fine.

The part I need advice on is the right way to keep the badge count updated whenever the queue is updated. (The queue can be updated by various components of the app - e.g., from the user manually adds items to the queue and from MyIntentService sending queued items to the server).

My queue_table is accessible via a ContentProvider in the app, so what I essentially need to know is the best way to monitor this content provider for changes (so the badge icon can be updated accordingly).

I am wondering if the best (or only) solution would be for me to create a MyApplication class that registers a ContentObserver in its onCreate method - e.g.,

MyApplication.java

@Override
public void onCreate() {
    super.onCreate();

    /*
     * Register for changes in queue_table, so the app's badge number can be updated in MyObserver#onChange()
     */
    Context context = getApplicationContext();
    ContentResolver cr = context.getContentResolver();
    boolean notifyForDescendents = true;
    myObserver = new MyObserver(new Handler(), context);
    cr.registerContentObserver(myContentProviderUri, notifyForDescendents, myObserver);


}

Also, if I do use such a solution, would I need to worry about unregistering myObserver and, if so, how would I do that in MyApplication?

Answer 1

The way I did it was to use a ContentObserver in my MyApplication class.

If you don't have a MyApplication class already, you need to specify it in your manifest file by adding the android:name=".MyApplication" attribute to your <application /> element.

Then you create the the MyApplication class that contains a ContentObserver like this:

package com.example.myapp;

import android.app.Application;
import android.content.ContentResolver;
import android.content.Context;
import android.database.ContentObserver;
import android.net.Uri;
import android.os.Handler;

public class MyApplication extends Application {

    private static String LOG_TAG = MyApplication.class.getSimpleName();

    public MyApplication() {
        super();
    }

    private MyContentObserver myContentObserver = null;

    @Override
    public void onCreate() {
        super.onCreate();


        /*
         * Register for changes in tables associated with myUri, so the app's badge number can be updated in MyContentObserver#onChange()
         */
        myContentObserver = new MyContentObserver(new Handler(), this);
        ContentResolver cr = getContentResolver();
        boolean notifyForDescendents = true;
        Uri[] myUri = ...;
        cr.registerContentObserver(myUri, notifyForDescendents, myContentObserver);

    }

    private class MyContentObserver extends ContentObserver {

        public MyContentObserver(Handler handler, Context context) {
            super(handler);
        }

        @Override
        public void onChange(boolean selfChange) {
            this.onChange(selfChange, null);
        }

        @Override
        public void onChange(boolean selfChange, Uri uri) {

            Utilities.updateBadgeCount();

        }

    }

}