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January 26, 2012

Yosuke Matsuda

Amazon DynamoDB is a fast, highly scalable, highly available, cost-effective, non-relational database service. Amazon DynamoDB removes traditional scalability limitations on data storage while maintaining low latency and predictable performance. The sample mobile application described here demonstrates how to store user preferences in Amazon DynamoDB. Because more and more people are using multiple mobile devices, connecting these devices to the cloud, and storing user preferences in the cloud, enables developers to provide a more uniform cross-device experience for their users.

This article shows sample code for the Android platform. The complete sample code and project files are included in the AWS SDK for Android. Links to the SDK are available at the end of this article.

To use the sample app, you'll need to deploy a token vending machine (TVM). A TVM is a cloud-based application that manages AWS credentials for users of mobile applications. To deploy the TVM, you'll first need to obtain your own AWS credentials: an Access Key ID and Secret Key.

If you haven't already signed up for Amazon Web Services (AWS), you will need to do that first to get your AWS credentials. You can sign up for AWS here. After you sign up, you can retrieve your credentials at this page. The credentials will be used to set up the TVM to authenticate users of AWS mobile applications. Sample Java web applications are available here: Anonymous TVM and Identity TVM (this sample uses Anonymous TVM).

Overview

In Amazon DynamoDB, a database is a collection of tables. A table is a collection of items, and each item is a collection of attributes. For our app, we create a single table to store our list of users and their preferences. Each item in the table represents an individual user. Each item has multiple attributes, which include the user's name and their preferences. Each item also has a hash key—in this case, userNo—which is the primary key for the table.

The app demonstrates how to add and remove users, and modify and retrieve their preference data. The app also demonstrates how to create and delete Amazon DynamoDB tables.

Registering the Device with Token Vending Machine

In order to create an Amazon DynamoDB client, we must first register the mobile device with the token vending machine (TVM). For this sample, we use the Anonymous TVM to register the device. Then we store the UID and key returned by the TVM on the device.

RegisterDeviceRequest registerDeviceRequest = 
                                        new RegisterDeviceRequest(this.endpoint, this.useSSL, uid, key);ResponseHandler handler = new ResponseHandler();response = this.processRequest(registerDeviceRequest, handler);if (response.requestWasSuccessful()) {	AmazonSharedPreferencesWrapper.registerDeviceId(this.sharedPreferences, uid, key);}

Retrieving the Temporary Credentials from Token Vending Machine

The following code demonstrates how to request that the TVM generate temporary credentials, and how to store the returned credentials on the device.

Request getTokenRequest = new GetTokenRequest(this.endpoint, this.useSSL, uid, key);ResponseHandler handler = new GetTokenResponseHandler(key);GetTokenResponse getTokenResponse = 
                                (GetTokenResponse) this.processRequest(getTokenRequest, handler);if (getTokenResponse.requestWasSuccessful()) {	AmazonSharedPreferencesWrapper.storeCredentialsInSharedPreferences(			this.sharedPreferences, getTokenResponse.getAccessKey(),			getTokenResponse.getSecretKey(),			getTokenResponse.getSecurityToken(),			getTokenResponse.getExpirationDate());}

Creating an Amazon DynamoDB Client

To make service requests to Amazon DynamoDB, you need to instantiate an Amazon DynamoDB client. The code below shows how to create an Amazon DynamoDB client for Android using the stored temporary credentials from the TVM.

AWSCredentials credentials = AmazonSharedPreferencesWrapper		.getCredentialsFromSharedPreferences(this.sharedPreferences);AmazonDynamoDBClient ddb = new AmazonDynamoDBClient(credentials);

Creating a User List (Table Creation)

Each user's preferences are stored as items in an Amazon DynamoDB table. The following code creates that table using the client we created above. Every Amazon DynamoDB table require a hash key. In this sample, we use userNo as the hash key for the table.

AmazonDynamoDBClient ddb = UserPreferenceDemoActivity.clientManager.ddb();KeySchemaElement kse = new KeySchemaElement()
                                                    .withAttributeName("userNo")
                                                    .withAttributeType(ScalarAttributeType.N);KeySchema ks = new KeySchema().withHashKeyElement(kse);ProvisionedThroughput pt = 
                new ProvisionedThroughput().withReadCapacityUnits(10l).withWriteCapacityUnits(5l);CreateTableRequest request = new CreateTableRequest()		                               .withTableName(PropertyLoader.getInstance().getTestTableName())                                               .withKeySchema(ks)
                                               .withProvisionedThroughput(pt);ddb.createTable(request);

Checking the Status of the Table (Table Description)

Before we can move to the next step (creating users), we must wait until the status of the tables is ACTIVE. To retrieve the status of the table, we use a describe table request. This request returns information about the table such as the name of the table, item count, creation date and time, and its status.

AmazonDynamoDBClient ddb = UserPreferenceDemoActivity.clientManager.ddb();DescribeTableRequest request = new DescribeTableRequest()		.withTableName(PropertyLoader.getInstance().getTestTableName());DescribeTableResult result = ddb.describeTable(request);String status = result.getTable().getTableStatus();

Creating Users (Item Creation)

For each user, we'll create an item in the table. An item is a collection of attribute/value pairs. For each item, we'll have three attributes: userNo, firstName, and lastName. These are added to a put item request in order to create the item.

HashMap<String, AttributeValue> item = new HashMap<String, AttributeValue>();AttributeValue userNo = new AttributeValue().withN(String.valueOf(i));item.put("userNo", userNo);AttributeValue firstName = new AttributeValue().withS(Constants.getRandomName());item.put("firstName", firstName);AttributeValue lastName = new AttributeValue().withS(Constants.getRandomName());item.put("lastName", lastName);PutItemRequest request = new PutItemRequest().withTableName(		PropertyLoader.getInstance().getTestTableName()).withItem(item);ddb.putItem(request);

Deleting Users (Item Deletion)

To remove a user from the list simply means deleting the corresponding item from the table. We specify the item we wish to delete using the hash key for the item.

AmazonDynamoDBClient ddb = UserPreferenceDemoActivity.clientManager.ddb();Key primaryKey = new Key().withHashKeyElement(targetValue);DeleteItemRequest request = new DeleteItemRequest().withTableName(		PropertyLoader.getInstance().getTestTableName()).withKey(primaryKey);ddb.deleteItem(request);

Listing Users (Table Scan)

We can retrieve a collection of users with a scan request. A scan request simply scans the table and returns the results in an undetermined order. Scan is an expensive operation and should be used with care to avoid disrupting your higher priority production traffic on the table. See the Amazon DynamoDB developer guide for more recommendations for safely using the Scan operation.

AmazonDynamoDBClient ddb = UserPreferenceDemoActivity.clientManager.ddb();ScanRequest request = new ScanRequest();request.setTableName(PropertyLoader.getInstance().getTestTableName());ScanResult result = ddb.scan(request);ArrayList<HashMap<String, AttributeValue>> users = 
                      (ArrayList<HashMap<String, AttributeValue>>) result.getItems();

Retrieving a User's Preferences (Item Retrieval)

Knowing a user's userNo, the hash key of the table, it is easy to find the item for the user. This next snippet shows how to get all the attributes for an item using the hash key.

AmazonDynamoDBClient ddb = UserPreferenceDemoActivity.clientManager.ddb();AttributeValue userNoAttr = new AttributeValue().withN(String.valueOf(userNo));Key primaryKey = new Key().withHashKeyElement(userNoAttr);GetItemRequest request = new GetItemRequest().withTableName(		PropertyLoader.getInstance().getTestTableName()).withKey(primaryKey);GetItemResult result = ddb.getItem(request);HashMap<String, AttributeValue> userPreferences = 
                                        (HashMap<String, AttributeValue>) result.getItem();

Modifying User Preferences (Item Update)

The hash key also makes it easy to update an attribute for an item.

AmazonDynamoDBClient ddb = UserPreferenceDemoActivity.clientManager.ddb();AttributeValue av = new AttributeValue().withS(value);AttributeValueUpdate avu = new AttributeValueUpdate().withValue(av).withAction(AttributeAction.PUT);Key primaryKey = new Key().withHashKeyElement(targetValue);HashMap<String, AttributeValueUpdate> updates = new HashMap<String, AttributeValueUpdate>();updates.put(key, avu);UpdateItemRequest request = new UpdateItemRequest()		.withTableName(PropertyLoader.getInstance().getTestTableName())		.withKey(primaryKey).withAttributeUpdates(updates);ddb.updateItem(request);

List Deletion (Table Deletion)

The easiest way to remove all the user preference data is to delete the Amazon DynamoDB table. The following code shows how:

AmazonDynamoDBClient ddb = UserPreferenceDemoActivity.clientManager.ddb();DeleteTableRequest request = new DeleteTableRequest()		.withTableName(PropertyLoader.getInstance().getTestTableName());ddb.deleteTable(request);

Conclusion and Additional Resources

The code in this article demonstrates how to use Amazon DynamoDB as a storage device for your mobile application. You can find more information about Amazon DynamoDB here.

Sample apps that include the code from this article are provided with the AWS SDK for Android. You can download the SDK using the following link:

AWS SDK for Android

For more information about using AWS credentials with mobile applications see the following article:

Authenticating Users of AWS Mobile Applications with a Token Vending Machine

Questions?

Please feel free to ask questions or provide comments in the Mobile Development Forum.

January 06, 2012

Amazon Mobile App Distribution Program

Interested in learning more about selling your apps on Amazon.com and Kindle Fire? Aaron Rubenson, director of the Amazon Appstore for Android, will offer insight at CES into how developers can get in front of millions of Amazon customers  – and make money – when they sell their apps at Amazon.com.

Learn about submitting apps for Kindle Fire,  which topped Amazon.com’s “Best of 2011” list as the best-selling, most wished for, and most gifted product as determined by Amazon.com customers. Throughout December, customers purchased well over 1 million Kindle devices per week. Also on the agenda is information about programs such as in-app purchasing and Test Drive, which lets customers try an app on their computers before they buy.

  AaronRubenson

Rubenson and other Amazon Appstore representatives will be available for informal discussions after the presentation.

Who:  Aaron Rubenson, Director, Amazon Appstore for Android

What:  “Selling Apps on Amazon.com and Kindle Fire”

Where:  The Venetian Meeting Rooms, Veronese 2404

When:  Friday, January 13, 9 a.m. – no R.S.V.P. needed

December 21, 2011

lisamar

One great benefit to having your app on the Amazon Appstore for Android is cross-promotion. Cross-promotion is a form of marketing where customers of one product are targeted with promotion of a related product. Amazon.com has millions of customers, and those customers purchase tens of thousands of products every day. With so many great products (and customers), we have the unique ability to employ cross-promotion, even across product categories.

So, what do you need to do? Nothing! By default, apps that are published in the Amazon Appstore qualify to get picked up in the cross-merchandising widgets and promotions.

In the below image, you’ll see the product detail page for an Android app. In the Customers Who Bought Related Items Also Bought widget right below the general app information, you see that our site is automatically recommending a USB cable to the customer who is interested in this app—simply because other customers purchased similar items.

Calengoo-other-items

 

Similarly, in the following image, you can see the Customers Who Bought This Item Also Bought widget. This form of cross-promotion allows customers to make informed decisions about which apps they purchase while also showing them additional apps that might interest them.

Customers_Who_Bought_This_Item_Also_Bought

Another Amazon widget that can benefit your app is the What Other Items Do Customers Buy After Viewing This Item? widget. Below, the widget is appearing on the product detail page for a tablet device and is advertising an app that was purchased by a customer who also purchased the tablet.

Automated Merchandisting slot promotes recent FAD_edit

All of the above-mentioned widgets are automated, but we also have the ability to manually cross-promote your app. In the following image, note that on the product detail page for a hardcover copy of this Dr. Seuss book, we’ve added a recommendation for the related Android app.

Cross-promotion screenshot

Cross-promotion means customers can discover your app in a number of ways—not just by searching on the title or category. And over time, your app sales have the potential to increase, purely based on this cross-promotion. That’s never a bad thing, right?

December 16, 2011

gdierkes

Overview

This article discusses how mobile apps can use Amazon Web Services to communicate with users via e-mail, short message service (SMS), and other communication channels. The sample code presented here uses Amazon Simple Notification Service and Amazon Simple Queue Service. Amazon Simple Notification Service (Amazon SNS) makes it easy to set up, manage, and send notifications from mobile apps and have these notifications delivered immediately to any users who have chosen to subscribe to them. Amazon SNS provides a highly scalable, flexible, and cost-effective method to implement such notification systems.

Amazon Simple Queue Service (Amazon SQS), also discussed here, offers a reliable, highly scalable, hosted queue for storing messages. The types of messages supported by Amazon SQS include—but aren't limited to—the notification messages sent from Amazon SNS.

Together, Amazon SNS and Amazon SQS enable developers to create apps that can message large numbers of users in multiple formats quickly and easily.

The sample app described here demostrates how mobile apps can message their users through Amazon SNS and Amazon SQS. The sample demonstrates how to use Amazon SNS to create a topic, subscribe users to that topic, and publish notifications to the topic. Subscribers to the topic can receive their notifications via e-mail, SMS, or an Amazon SQS queue. Amazon SQS and Amazon SNS can also be used to create other types of communication systems not shown here.

This article shows sample code but the complete sample code and project files are included in the AWS SDK for Android. A link to the SDK is available at the end of this article.

To use the AWS SDK for Android, you will need AWS credentials, that is, an Access Key ID and Secret Access Key. If you haven't already signed up for Amazon Web Services (AWS), you will need to do that first to get your credentials. You can sign up for AWS here. After you sign up, you can retrieve your credentials at this page.

Creating Amazon SQS and Amazon SNS Clients

Making requests to Amazon SNS and Amazon SQS requires creating a client for each service. The code below shows how to create a client:

AWSCredentials credentials =      new BasicAWSCredentials( Constants.ACCESS_KEY_ID, Constants.SECRET_KEY );		AmazonSNSClient snsClient = new AmazonSNSClient( credentials );AmazonSQSClient sqsClient = new AmazonSQSClient( credentials );

Topic Creation

Amazon SNS uses topics to route notifications from publishers to subscribers. The term publisher refers to an app that sends notifications; the term subscriber refers to an entity, such as a user, that receives notifications. Topics provide a junction point for publishers and subscribers to communicate with each other. Once a topic is created, subscribers can be added to the topic and receive notifications/messages. The DisplayName attribute is added to a topic to allow notifications to be sent via SMS.

CreateTopicRequest ctr = new CreateTopicRequest( Constants.TOPIC_NAME );CreateTopicResult result = snsClient.createTopic( ctr );	        SetTopicAttributesRequest tar      = new SetTopicAttributesRequest( result.getTopicArn(), "DisplayName", "MessageBoard" );this.snsClient.setTopicAttributes( tar );  

Subscribing to Topics

In order for notifications sent to a topic to be received, you have to subscribe an endpoint to that topic. The endpoint corresponds to a recipient. An endpoint is an e-mail address, SMS number, web server, or Amazon SQS queue. If you are using an Amazon SQS queue, it needs to be configured to receive notification messages from Amazon SNS. Once you subscribe an endpoint to a topic and the subscription is confirmed, the endpoint will receive all messages published to that topic.

SubscribeRequest sr = new SubscribeRequest( this.topicARN, "email", email );this.snsClient.subscribe( sr );

Listing a Topic's Subscribers

Listing the subscribers for a topic provides the endpoint and corresponding protocol for each subscriber who receives notification via that topic. The protocol for an endpoint depends on the type of endpoint. For example, endpoints that are e-mail addresses have a protocol of SMTP.

ListSubscriptionsByTopicRequest ls = new ListSubscriptionsByTopicRequest( this.topicARN );ListSubscriptionsByTopicResult response = this.snsClient.listSubscriptionsByTopic( ls );return response.getSubscriptions();

Publishing Notifications

Publishers send notifications to topics. Once a new notification is published, Amazon SNS attempts to deliver that notification to every endpoint that is subscribed to the topic.

PublishRequest pr = new PublishRequest( this.topicARN, message );this.snsClient.publish( pr );	

Unsubscribing from Topics

Unsubscribing removes the endpoint from the topic and stops notifications from being received.

UnsubscribeRequest unsubscribeRequest = new UnsubscribeRequest( subscriptionArn );this.snsClient.unsubscribe( unsubscribeRequest );

Creating a Queue

The first task in using Amazon SQS is to create a queue. Once a queue is created it can be subscribed as an endpoint to an Amazon SNS topic.

CreateQueueRequest cqr = new CreateQueueRequest( Constants.QUEUE_NAME );CreateQueueResult result = this.sqsClient.createQueue( cqr );return result.getQueueUrl();

Subscribing a Queue to a Topic

Here's how to subscribe a queue to a topic. However, for the queue to receive messages, you must also add a policy to the queue. See below.

String queueArn = this.createMessageQueue();		SubscribeRequest request = new SubscribeRequest();request.withEndpoint( queueArn ).withProtocol( "sqs" ).withTopicArn( this.topicARN );		this.snsClient.subscribe( request );

Adding a policy to a Queue

In order for a queue to receive messages from a topic, the queue must have a policy object that specifies that the topic has sqs:SendMessage permission for the queue. For further details see the Amazon SNS FAQ. For more information about queue policies see the Amazon SQS documentation. Once the policy object is created it can be attached to the queue as follows:

HashMap attributes = new HashMap();attributes.put("Policy", generateSqsPolicyForTopic( queueArn, this.topicARN ) );this.sqsClient.setQueueAttributes(new SetQueueAttributesRequest( queueUrl, attributes ) );

Receiving Messages from a Queue

Now that a message is in the queue, you can receive it, which requires getting it from the queue. When requesting to get a message from the queue, you can't specify which message to get. Instead, you simply specify the maximum number of messages you want to get (up to 10), and Amazon SQS returns up to that maximum number. Because Amazon SQS is a distributed system and the particular queue we're working with here has very few messages in it, the response to the receive request might be empty. Therefore, you should rerun the sample until you get the message. You should design your own app so that it continues to poll the queue until it gets one or more messages.

ReceiveMessageRequest rmr = new ReceiveMessageRequest( this.queueUrl );rmr.setMaxNumberOfMessages( 10 );rmr.setVisibilityTimeout( 30 );ReceiveMessageResult result = this.sqsClient.receiveMessage( rmr );

Delete Messages from a Queue

Amazon SQS doesn't automatically delete a message after returning it to the app. By default, it keeps the message to protect against the case where the receiving app fails or loses its connection. In these cases, a different app—or perhaps a new instance of the same app— might attempt to get the message.

To delete the message, you must send a separate request. You specify which message to delete by providing the receipt handle that Amazon SQS returned when you received the message. You can delete only one message per call. Deleting the message acknowledges that you've successfully received and processed it.

DeleteMessageRequest request      = new DeleteMessageRequest( this.queueUrl, message.getReceiptHandle() );this.sqsClient.deleteMessage( request );

References

A sample app that includes this code is provided with the SDK. The download link can be found on the following page:

For more information about using AWS credentials with mobile apps see the following article:

Questions?

Please feel free to ask questions or provide comments in the Mobile Development Forum.

November 30, 2011

gdierkes

Screen shot 2011-11-29 at 10.40.45 AM

This article highlights the benefits of connecting mobile devices to the cloud while also presenting an Amazon SimpleDB use case. Amazon SimpleDB is a highly available, flexible, and scalable non-relational data store that offloads the work of database administration. The app described here demonstrates how to store a high score list or leader board in SimpleDB. The app enables the user to view the high scores sorted by name or score, add and remove scores, and more. This article shows sample code for the Android platform. The complete sample code and project files are included in the AWS SDK for Android. A link to the SDK is available at the end of this article.

To use the AWS SDK for Android, you will need your AWS credentials, that is, your Access Key ID and Secret Access Key. If you haven't already signed up for Amazon Web Services (AWS), you will need to do that first to get your AWS credentials. You can sign up for AWS here. After you have signed up, you can retrieve your credentials at this page.

Overview

SimpleDB stores data in domains. Each domain is a collection of items and each item is a collection of attribute/value pairs. For the app, we create a single domain to store our high score list. Each item in the domain represents an individual player. The items will have two attributes, the player's name and their score. Items also have a unique identifier called the item name that, in this case, is equal to the player's name. Storing the player's name and score as item attributes enables us to sort the items by name or score.

The app demonstrates how to add and remove individual players, sort the scores by player name or score, and retrieve a single item from the domain. The app also demonstrates how to create and delete SimpleDB domains.

Creating a SimpleDB Client

Making requests to SimpleDB requires a client. Creating a SimpleDB client for Android is shown below.

AWSCredentials credentials = new BasicAWSCredentials(ACCESS_KEY_ID, SECRET_KEY);AmazonSimpleDBClient sdbClient = new AmazonSimpleDBClient( credentials);

High Score List Creation (Domain Creation)

Individual player scores are stored as items in a SimpleDB domain. This requires that we create the domain first. Using the appropriate client that we created above, we can use the following code to create the domain.

CreateDomainRequest cdr = new CreateDomainRequest( HIGH_SCORES_DOMAIN );sdbClient.createDomain( cdr );

Add Score (Item Creation)

An item is a collection of attribute/value pairs. For our items, we create two attributes, one for the player's name and one for the player's score. These are added to a request along with an item name in order to create the item. Because a player appears at most only once on the high score list, we use the player's name to uniquely identify each item. All data in SimpleDB are stored as strings, therefore numbers must be zero padded if you want to sort them properly. The AWS SDK for Android includes a utility to pad numbers, used below.

String paddedScore = SimpleDBUtils.encodeZeroPadding( score, 10 );		ReplaceableAttribute playerAttribute =     new ReplaceableAttribute(PLAYER_ATTRIBUTE, player, Boolean.TRUE);ReplaceableAttribute scoreAttribute =     new ReplaceableAttribute(SCORE_ATTRIBUTE, paddedScore, Boolean.TRUE);		List attrs = new ArrayList(2);attrs.add( playerAttribute );attrs.add( scoreAttribute );		PutAttributesRequest par = new PutAttributesRequest(HIGH_SCORES_DOMAIN, player, attrs);		sdbClient.putAttributes( par );

Remove Score (Item Deletion)

Removing a score from the list simply means deleting an item from the domain. Deleting an item requires the unique name for the item you wish to delete. In SimpleDB, deleting an item is done by removing all the attributes from that item. Invoking deleteAttributes with no specified attributes removes all the attributes by default.

DeleteAttributesRequest dar = new DeleteAttributesRequest( HIGH_SCORES_DOMAIN, player );sdbClient.deleteAttributes( dar );

Player View (Getting an Item)

Knowing an item's name makes it easy to find the item. This next snippet shows how to get all the attributes for an item using the item name. Note that items may contain many attributes and values.

GetAttributesRequest gar = new GetAttributesRequest( HIGH_SCORES_DOMAIN, player );GetAttributesResult response = sdbClient.getAttributes(gar);

List View and Sorting (Select)

Getting a collection of scores, sorted by player name or the score itself requires the use of a select request. A select request uses a simple query language to determine which items to match and what data to return and how. Select requests are paginated because the number of items matching the query can be large. Therefore, select requests return a next token that enables you to "page" through the data in an ordered fashion. The code here shows how to return items ordered by score from highest to lowest. Only the score and player attributes are returned. More information regarding SimpleDB queries can be found in a reference article linked below.

String select = "select player, score from HighScores where score >= '0' order by score desc";SelectRequest selectRequest = new SelectRequest( select ).withConsistentRead( true );selectRequest.setNextToken( nextToken );		SelectResult response = sdbClient.select( selectRequest );nextToken = response.getNextToken();

List Deletion (Domain Deletion)

The quickest and easiest way to remove the entire high score list would be to delete the SimpleDB domain. Here is how to do that.

DeleteDomainRequest ddr = new DeleteDomainRequest( HIGH_SCORES_DOMAIN );sdbClient.deleteDomain(ddr);

Conclusion

The code in this article demonstrates how to use Amazon SimpleDB as an indexed storage device for your app. The complete sample app is included as part of the AWS mobile SDKs, which are linked below. The reference section also contains a link to a SimpleDB article which discusses writing queries for SimpleDB in detail.

References

Find more information about SimpleDB here.

A sample app that includes this code is provided with the AWS SDK for Android

For more information about using AWS credentials with apps see the article, Authenticating Users of AWS Mobile Applications with a Token Vending Machine
 

Questions?

Please feel free to ask questions or provide comments in the Mobile Development Forum.

November 28, 2011

lisamar

KO-aag-apps._V162619036_
 

Recently Amazon released Kindle Fire, our newest addition to the Kindle family that showcases a color touch display and provides instant access to the Amazon Appstore for Android and Amazon’s massive selection of digital content, as well as free storage in the Amazon Cloud.

Kindle Fire puts Amazon’s digital powerhouse of content at customers’ fingertips. In addition to the thousands of popular apps and games available in the Amazon Appstore for Android, customers can also choose from over 18 million movies, TV shows, songs, magazines, and books—and all of their Amazon content is automatically stored in the Amazon cloud, free of charge. Web browsing is simple and fast with Amazon Silk and an even better experience because of the Kindle Fire’s vibrant color touchscreen with an extra-wide viewing angle. All this, plus a fast, powerful dual-core processor, and an unbeatable price, make us proud of this newest member of our Kindle family.

Don’t take our word on it though—we’re not the only ones admiring Kindle Fire!

The first easy-to-use, affordable small-screen tablet, the Amazon Kindle Fire is revolutionary...I can't emphasize this "ease of use" thing enough. More than anything else, that's what's been holding non-iPad tablets back. Amazon cracked it. End of story." - PC Mag

"The Kindle Fire is a 7-inch tablet that links seamlessly with Amazon's impressive collection of digital music, video, magazine, and book services in one easy-to-use package. It boasts a great Web browser, and its curated Android app store includes most of the big must-have apps (such as Netflix, Pandora, and Hulu). The Fire has an ultra-affordable price tag, and the screen quality is exceptional for the price." – CNET

How do you get your app onto the Kindle Fire?

Submit it! Simply join the Amazon Appstore Developer Program, if you haven’t already, and submit your app using the Amazon Appstore Developer Portal just as you would if you were submitting to our store for any other supported Android device. All apps will go through regular Amazon Appstore testing, as well as testing for Kindle Fire.

What are the requirements for your app to work on Kindle Fire?

For your app to work on Kindle Fire, it needs to be compatible with the device's specifications. At a high level, it must be optimized for non-Google Mobile Services (GMS), Android 2.3.4 (Gingerbread), and a 7" screen with a resolution of 1024 x 600. Your app cannot require a gyroscope, camera, WAN module, Bluetooth, microphone, GPS, or micro-SD to function. In addition, your app must not be a theme or wallpaper that manipulates the user interface of the device. As with any other app submission to the Amazon Appstore for Android, your app will also need to comply with our Content Guidelines. For additional information, please visit our Kindle Fire FAQs.

What if your app was already submitted - will it be considered?

Yes. If you already have an app published in the Amazon Appstore for Android, we will automatically review the app for Kindle Fire compatibility. We're currently in the process of testing our entire catalog of published apps to ensure each app provides a high-quality customer experience on Kindle Fire.

What if you want to test your app(s) prior to submitting?

We strongly recommend you test your app on your own and submit an update if you discover any problems. It is possible to configure a standard Android emulator to simulate the Kindle Fire device platform. You should configure your emulator with the following characteristics:

  • Width: 600px
  • Height: 1024px (the device will reserve 20px of the height to display a soft key menu, yielding a height of 1004px when in full-screen mode)
  • Abstracted LCD Density: 169
  • Target: Android 2.3.4 - API Level 10
  • RAM: 512 MB

If you haven’t already submitted your apps, submit via the Amazon Appstore Developer Portal. Interested in marketing opportunities?  Fill out our marketing request form.

November 22, 2011

Amazon Mobile App Distribution Program

Carlos M. Icaza is our guest blogger for this post. Carlos is the co-founder of Ansca, Inc., the maker of the Corona SDK.

Whether you're brand new to Android development or a veteran developer who has some experience with other mobile-app platforms, this tutorial will walk you through the process of creating, building, and submitting the iOS version of your apps to the Amazon Appstore for Android using the Corona SDK.
 

The primary differences between Android apps and those on other platforms from a Corona-developer’s standpoint really include these things: configuration for different screen sizes, Keystores, the build process, and of course, the final submission. This tutorial will go over all of these crucial points, as well as the process of building and submitting your Corona apps to the Amazon Appstore for Android.

Configuring Your App

The very first thing you should do is ensure your app is going to look good on the various Android devices you plan to target. In Corona, this is as easy as editing your config.lua file and adjusting the width, height, and scale settings, and optionally making changes to your code to ensure everything is positioned just where you want it.

If you are targeting tablets, you should set the width and height in your config.lua file to 600 and 1024 respectively (or similar). The scale mode you choose to use is completely up to you, but if you plan on supporting many different devices and screen sizes, options like "letterBox" and "zoomStretch" may be better for your project.

Additional information on configuring Corona projects can be found here.

Android Permissions

Next, you need to decide what kind of Android permissions your app will need, and then add them to your build.settings file. For example, if your app needs to access the Internet, and you want to be able to save files, then at minimum, your build.settings needs to include the following:

settings = {
    androidPermissions = {
        "android.permission.INTERNET",
        "android.permission.WRITE_EXTERNAL_STORAGE"
    }
}

A complete list of Android permissions (with descriptions) can be found here.

App Icons

Every app needs an Icon, and in the case of building an app for the Amazon Appstore for Android, your project folder should have at least three: Icon-ldpi.png (36x36), Icon-mdpi.png (48x48), and Icon-hdpi.png (72x72). Pay particularly close attention to the letter-case of the icon filenames (hint: the first letter is uppercase).

Building for Android

In Corona, go to File > Open and locate your project's folder. Next, go to File > Build > Android and a dialog box will show. Fill in your app's name, version, and unique package identifier.

Once everything is in place, double-check to make sure everything is correct and click the “Build” button in the lower-right corner of the dialog. In a few minutes (or less), you'll be notified that the build process is complete, and your APK will be ready for submission.

Submitting Your App

Now that you got all the technical stuff out of the way, it's time for the fun part.

Go to the Amazon Appstore Developer Portal and log in with your developer portal account. If you don’t have an account, you can sign up on the same page so you can begin submitting apps to the Amazon Appstore for Android. If you plan on selling apps for a price, be sure to get your Payment information set up at this time as well (you need to do this before submitting your app).

How we ported Corona Indie Bundle to Android

To get our Corona Indie Bundle into the Amazon Appstore for Android, basically all we did was test against a number of Android devices to see how the gameplay and graphic images would work and behave in the different Android form factors. Once we tested the games in various devices, we submitted the game to the Amazon Appstore for Android, where it was subjected to more testing by the Amazon ingestion process. Once we determined some quirks on some devices we did not have access to, we immediately fixed the issue and resubmitted without a problem.

Exclusive discount offer for Corona SDK’s Corona Project Manager

We have a promotion for you. Purchase a PRO subscription to the Corona SDK, at $349.00 for a one-year subscription at http://www.anscamobile.com/get-corona?amazonappstorepromo, and receive a copy of the Corona Project Manager, http://coronaprojectmanager.com/, a $74.99 product, for free. Enter promo code "AMAZONANSCAPROMO". This offer is valid until Dec. 31, 2011 only with a PRO subscription of the Corona SDK.

This promotion is offered by Ansca Inc.  It is not offered or sponsored by Amazon or the Amazon Appstore for Android.

November 14, 2011

amberta

Kindle Fire ships today, and we think this is a huge win for Amazon.com customers and Amazon Appstore for Android developers.  As we mentioned in a Kindle Fire announcement blog post, Kindle Fire boasts Amazon’s incredible selection of digital content at customers’ fingertips:

  • Amazon Appstore for Android – thousands of popular apps and games
  • 18 million movies, TV shows, songs, magazines, and books
  • Ultra-fast web browsing - Amazon Silk 
  • Free cloud storage for all your Amazon content
  • Vibrant color touchscreen with extra-wide viewing angle  
  • Fast, powerful dual-core processor 

For Amazon Appstore developers, Kindle Fire offers another venue for getting your apps in front of potential customers. You’ll start seeing Kindle Fire, and apps that were Amazon-tested on Kindle Fire for the best experience possible, sprinkled throughout Amazon.com and in the Amazon Appstore marketing campaigns, in addition to the placements where we’ve already been showcasing apps. You can view a selection of some of our favorite Kindle Fire apps in the Amazon Appstore here.

Some of the titles you may have seen in recent press include Netflix, Rhapsody, Pandora, Comics by comiXology, Facebook, The Weather Channel and popular games from Zynga, EA, Gameloft, PopCap, and Rovio.  Thousands of the Amazon Appstore editorial team’s favorites, such as Bird’s the Word, Pinball Deluxe, SketchBook Mobile, Super Sudoku, X Construction, Monkey Preschool Lunchbox, and more are available as well.

What does this mean for you?
As always, we encourage you to ensure you have submitted the most current versions of all your apps to the Amazon Appstore for Android. Now is also a good time to verify that each app’s meta-data (including list price) is up-to to-date. You can update your existing apps and submit new apps using the Amazon Appstore Developer Portal.

Where can you find the technical specifications for Kindle Fire?
The Kindle Fire has a 7” multi-touch display with 1024 x 600 pixel resolution at 169 ppi, can display 16 million colors, and has instant access to the Amazon Appstore for Android. For more detailed information about the device, including technical specifications, app compatibility information, development tips, and instructions for submitting your app, please see our Kindle Fire FAQ.

You can order a Kindle Fire to test your apps online at amazon.com/kindlefire.

How can developers get merchandising placement in the Amazon Appstore and on Kindle Fire?
If you have ideas about merchandising and marketing your app at the Amazon Appstore, or if you would like to be considered for Free App of the Day placement, please fill out the Marketing Proposal Form.

November 10, 2011

gdierkes

This article demonstrates how to use the AWS SDK for Android to uploadan image to Amazon Simple StorageService (S3) from your mobile device and how to make that imageavailable on the web. Amazon S3 is storage for the Internet. It's a simplestorage service that offers software developers a highly-scalable,reliable, secure, fast, and inexpensive data storage. The complete samplecode and project files are included in the AWS SDK for Android which canbe found here.

To use the AWS SDK for Android, you will need your AWS credentials,that is, your Access Key ID and Secret Access Key. If you haven'talready signed up for Amazon WebServices (AWS), you will need to do that first to get your AWScredentials. You can sign up for AWS here.

Here's what the sample app looks like at start up on Android:

Android-Uploader

Photo Upload

The app uses each platform's "image picker" utility to have theend-user select an image for upload. The app then creates an Amazon S3client, uses the client to create an Amazon S3 bucket in which to storethe image, and finally uploads the image into the bucket. A bucket is acontainer for objects stored in Amazon S3. Every object--such as animage--is contained within a bucket.      

Get the image

The first step is to retrieve the content, in this case an image, tobe uploaded to Amazon S3. For this sample app, selecting an image from thedevice itself is an easy choice.

Intent intent = new Intent(Intent.ACTION_GET_CONTENT);intent.setType("image/*");startActivityForResult(intent, PHOTO_SELECTED);

Android-Image-Picker

Once an image is selected, a callback method is invoked with theselected image's information. The app uses this information to completethe upload.

Upload the image

Once we have the image, we can attempt to upload it to Amazon S3.

First, create an Amazon S3 client to communicate withthe service.

AmazonS3Client s3Client =   new AmazonS3Client( new BasicAWSCredentials( MY_ACCESS_KEY_ID, MY_SECRET_KEY ) );

Second, create an Amazon S3 bucket to store thepicture.

s3Client.createBucket( MY_PICTURE_BUCKET );

Finally, put the image object into the Amazon S3bucket.

PutObjectRequest por =    new PutObjectRequest( Constants.getPictureBucket(),                          Constants.PICTURE_NAME,                          new java.io.File( filePath) );s3Client.putObject( por );

Browser Display

The app makes the image available for viewing in a browser bygenerating a pre-signed URL. A pre-signed URL is a URL for an Amazon S3resource that is signed with current AWS security credentials. Thepre-signed URL can then be shared with other users, allowing them toaccess resources without providing an account's AWS securitycredentials.

First, create an override content type to ensure thatthe "content" will be treated as an image by the browser.

ResponseHeaderOverrides override = new ResponseHeaderOverrides();override.setContentType( "image/jpeg" );

Second, create the pre-signed URL request. Pre-signedURLs can be created with an expiration date, that is, a date andtime after which the resource will no longer be available. In the sample,the pre-signed URLs are valid for only one hour.

GeneratePresignedUrlRequest urlRequest =    new GeneratePresignedUrlRequest( Constants.getPictureBucket(),                                     Constants.PICTURE_NAME );// Added an hour's worth of milliseconds to the current time.urlRequest.setExpiration(    new Date( System.currentTimeMillis() + 3600000 ) );urlRequest.setResponseHeaders( override );

Third, generate the pre-signed URL. 

URL url = s3Client.generatePresignedUrl( urlRequest );

Finally, launch the browser to view the pre-signed URLwhich will display the image. 

startActivity(    new Intent( Intent.ACTION_VIEW, Uri.parse( url.toURI().toString() ) ));

Android-ShowPic

Next Steps

These few lines of code demonstrate how Amazon S3 could become alimitless storage device for your mobile photos. A photo sharing app thatallows users to view photos from other users would not be a difficultextension to the above code. Also, the content that is uploaded and sharedis not limited to images. The content could be audio files, video files,text, or other content that users want to store and share. 

References

A sample app that includes this code is provided with both mobile SDKs.The download links can be found here: AWS SDK for Android.

For more information about using AWS credentials with mobileapplications see the following article: Authenticating Users of AWS Mobile Applications with a Token VendingMachine

Questions?

Please feel free to ask questions or make comments in the MobileDevelopment Forum.

Portions of this page are reproduced from work created and shared by Google and used according to terms described in the Creative Commons 3.0 Attribution License.

November 08, 2011

johnjord

Recently, the Amazon Appstore for Android featured Read It Later Pro as the Free App of the Day. The extremely popular and useful application allows users to save what they find on the web to watch and read on any device and at any time – a “DVR for the web,” states The New York Times.

Founded in 2007, the company already boasts 3.5 million users and sees millions of articles saved each week through their very user-friendly and seamless service.

Also, the company “runs the entire Read It Later operation on Amazon Web Services [AWS],” states founder Nate Weiner. “We take advantage of EC2 for our servers, ELB for load balancing, S3 and EBS for storage. We also use Amazon Simple Email Services [SES], which has simplified our e-mail communications and made them more effective.” Although very excited about the Free App of the Day promotion, the Read It Later team expressed some concern over the large number of expected new customers and the impact on their 50K daily e-mail limit through SES.

According to Read It Later CTO and Engineer Matt Koidin, the internal teams at Amazon moved quickly to address a solution for this use case. “We initially thought we would need additional development to work around the e-mail limit… but our account manager was able to coordinate with the AWS team to increase the limit for the day,” Koidin said.

Koidin and team see this as another example of the Amazon Appstore’s ability to provide an advantage through its network of services for developers. “Having Amazon not only run the promotion, but work with the broader Amazon organization (i.e. AWS) to provide some assistance so it didn’t overwhelm us or require additional work, shows they are aligned as a partner to make this a success for everyone involved,” added Koidin.

The team at Read It Later was happy to report that the promotion resulted in “one of our largest days of new user acquisition ever” and “we’ve seen our transaction level sustain at a higher level than prior to the promotion.” They see more exciting opportunities down the road to incorporate additional Amazon services for developers.  When asked if they would run the Free App of the Day promotion again, Koidin replied with a simple, “Absolutely.”

Learn more about AWS online here.

October 28, 2011

amberta

Last month we announced a promotion with Amazon Web Services (AWS) where qualifying developers who submit an Android app or app update to the Amazon Appstore for Android are eligible to receive a $50 AWS credit to use toward the following services:

Remember, there’s still time to submit. The promotion runs through November 15, 2011, and we encourage you to get your apps in soon. We encourage you to ensure you’ve submitted the current versions of all your apps to the Amazon Appstore. Now is also a good time to verify that each app’s meta-data (including list price) is up-to-date. You can update your existing apps and submit new apps using the Amazon Appstore Developer Portal.

For developers new to AWS, here’s a great video on how to get started:

Many developers have already qualified for and received their promotion code for AWS. AWS combined with the Amazon Appstore provide a solid suite of solutions to build apps and a great place to get exposure. MightyMeeting, an app that enables users to run online meetings on the go from tablets, smartphones, or any web-enabled device is one great example. “We needed a cost-efficient robust infrastructure that could be used to manage presentations and online meetings in the cloud and scale up or down dynamically depending on the workload. We found that AWS addresses all our needs, even real-time media streaming during a meeting,” says Dmitri Tcherevik, CEO of MightyMeeting Inc.

Learn more about the AWS SDK and this promotion online here. To apply your code, sign up for an AWS account and apply your promotion code by visiting: http://aws.amazon.com/awscredits/

Submit your app online here.
 

October 20, 2011

alexbow

Customer Reviews are extremely important to us here at Amazon. While it’s meaningful to make sure that your product description paints a compelling and realistic picture, we can’t always anticipate everything customers will be interested in before purchasing. When a customer leaves a review, they’re helping other customers decide if a particular item is right for them. This is just as important for the Amazon Appstore for Android. Customers are likely to view a few similar apps before choosing the one that suits them best and will use Customer Reviews to help make that determination.

Paying attention to the reviews on your apps has a lot of benefits. You can use the feedback to decide to add new features and functionality to your app, fix bugs, or make general improvements. While we understand you never want to see less than positive reviews posted about your app, you should take these comments as opportunities to improve your app and better serve your customer base. We give you the option of commenting on reviews so you can show the customer that their feedback is important and you are listening.

Here’s a great example: Capigami makes sure to follow customer reviews for their app, Out of Milk.  A review was posted that shared how much the customer loved Out of Milk but also had a few suggestions on improving the app.

Capture1

Capigami responded with a comment, thanking the customer for the kind words but also going through all of the recommendations and responding to each one. In this case, one of the recommendations was already in development.

Capture2

Amazon pays attention to customer reviews, too. We use that information to make decisions on many things, including which apps to market in various promotions, such as Free App of the Day or the Amazon Appstore for Android merchandising areas.

On Amazon.com, customer reviews are an extremely important part of our customers’ purchasing decisions. Ensuring that you stay on top of customer feedback will reward you with good customer reviews, which will get more customers interested in your app and other apps that you develop.

October 05, 2011

amberta

Last week Amazon announced the upcoming release of Kindle Fire.  Kindle-fire-screenshot

Kindle Fire is a new addition to  the Kindle family with a vibrant color touch display that offers instant access to the Amazon Appstore, along with Amazon’s massive selection of digital content and free storage in the Amazon Cloud.  A fast and powerful dual-core processor powers the 14.6-ounce device that’s light enough to hold with one hand—all for only $199.

Customers in the U.S. can pre-order Kindle Fire at www.amazon.com/kindlefire.  Read more in the press release.

What does this mean for you?
Kindle Fire ships on November 15.  We encourage you to ensure you have submitted the most current versions of all your apps to the Amazon Appstore for Android.  Now is also a good time to verify that each app’s meta-data (including list price) is up-to to-date.  You can update your existing apps and submit new apps using the Amazon Appstore Developer Portal.

Where can I find the technical specifications for Kindle Fire?

The Kindle Fire has a 7” multi-touch display with 1024 x 600 pixel resolution at 169 ppi, can display 16 million colors, and has instant access to the Amazon Appstore for Android.  For more detailed information about the device, including technical specifications, app compatibility information, development tips, and instructions for submitting your app, please see our Kindle Fire FAQ

How can developers get merchandising placement in the Amazon Appstore and on Kindle Fire?

If you have ideas about merchandising and marketing your app at the Amazon Appstore, or if you would like to be considered for Free App of the Day placement, please fill out the the Marketing Proposal Form.

We appreciate your interest in the Amazon Appstore for Android and the new Kindle Fire!

September 28, 2011

Amazon Mobile App Distribution Program

Kindle Fire is a new addition to the Kindle family with a vibrant color touch display that offers  instant access to the Amazon Appstore, along with Amazon’s massive selection of digital content and free storage in the Amazon Cloud. A fast and powerful dual-core processor powers the 14.6-ounce device that’s light enough to hold with one hand—all for only $199.Apps-on-kindle-fire

Kindle Fire puts Amazon’s incredible selection of digital content at customers’ fingertips:

  • Amazon Appstore for Android – thousands of popular apps and games
  • 18 million movies, TV shows, songs, magazines, and books
  • Ultra-fast web browsing - Amazon Silk 
  • Free cloud storage for all your Amazon content
  • Vibrant color touchscreen with extra-wide viewing angle  
  • Fast, powerful dual-core processor 

Key features:

Stunning Color Touchscreen: Content comes alive on a 7” vibrant color touchscreen that delivers 16 million colors in high resolution and an extra-wide viewing angle.

Fast Dual-Core Processor: Kindle Fire features a state-of-the-art dual-core processor for fast, powerful performance. Stream music while browsing the web or read books while downloading videos.

Easy to Hold in One Hand: Designed to travel with you wherever you go. Light enough to hold in just one hand, Kindle Fire is perfect for browsing, playing, reading and shopping on-the-go.

Beautifully Simple and Easy To Use: Designed from the ground up, Kindle Fire's simple, intuitive interface lets customers spin effortlessly through your recent titles and websites straight from the home screen.

Free Cloud Storage: Kindle Fire gives you free storage for all Amazon digital content in the Amazon Cloud. Apps, books, movies, and music are available instantly to stream or download for free, at a touch of a finger. 

Ultra-fast web browsing – Amazon Silk: Amazon Silk is a revolutionary, cloud-accelerated browser that uses a "split browser" architecture to leverage the computing speed and power of the Amazon Web Services cloud. Learn why it’s so fast

Only $199: The all-new Kindle Fire is only $199. Customers in the U.S. can pre-order Kindle Fire starting today at www.amazon.com/kindlefire, and it ships Nov. 15, 2011.

Read more in the press release.

September 20, 2011

lisamar

Vervv, a mobile developer specializing in finance and productivity apps, currently has two Android apps available in the Amazon Appstore for Android. They are Convertr, which instantly and accurately converts anything, from currency to torque, and Ledgerist, the Android solution to the old pen-and-paper balancing of the checkbook.

The Amazon Appstore team approached Vervv prior to the launch of the Amazon Appstore. Ultimately, Vervv’s decision to submit its apps came down to Amazon’s large and engaged customer base. “There aren't many companies out there with the size and reach that Amazon has,” Vervv co-founder James Kelso said.

Vervv was initially surprised by its lack of traction with other Android offerings. “We noted a great response to our release on iOS, but the market was just too saturated on Android. When we released to the Amazon Appstore, and we were featured as the Free App of the Day, we noted much better user engagement with our product. We've seen a significant increase in sales ever since,” Kelso said.

 
       Convertr_thumbnail_225x225 Ledgerist_thumbnail_225x227


   
Vervv has not had to deal with a lot of non-technical feedback for its app in the Amazon Appstore for Android, a very positive sign. Kelso explained, “We're constantly bombarded with e-mails from users of the other Android marketplaces needing us to fix billing issues or other non-technical issues. Because customers can reach out to Amazon.com customer service for help with app-related billing and non-technical issues, the Amazon Appstore has been great in that it takes that burden off our shoulders.”

Kelso recommends the Amazon Appstore for Android as a good place for emerging apps “because it's difficult to get separation in most segments these days. Amazon is big enough to help gain traction in the market.” He added, “The most important thing that we've learned is probably that your app could be discovered any day.”

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