This guide provides a walk-through of how to use the official Algorithmia Android Client to call algorithms and manage your data through the Algorithmia platform.
Here you will learn how to install the Android Client, work with the Data API by uploading and downloading files, create and update directories and permission types and last, you’ll learn how to call an algorithm that summarizes text files.
To follow along you can create a new project in Android Studio or your IDE of choice.
Getting Started with Algorithmia
The Algorithmia Android Client is published to Maven Central and can be added as a dependency in Android Studio in your Gradle file. Additional reference documentation can be found at Android Client Docs and for API documentation see the Algorithmia API docs.
Note: Because our Java Client depends on Apache HTTP Client, it is not compatible with the Android Runtime. In early versions of Android, a legacy version of apache http client came pre-bundled, but was not updated over time. In recent Android versions (6.0+) it was removed entirely. See Android docs here. The algorithmia-android client uses native HttpURLConnection as its underlying client, as recommended by the Android documentation.
To install the Algorithmia Android Client, add the following line to your
Now import the Algorithmia library and create the Algorithmia client:
Now you’re ready to start working with Algorithmia for Android development.
Working with Data Using the Data API
This guide will show you how to work with the Hosted Data option on the Algorithmia platform which is available to both algorithm and application developers.
If you wish to follow along working through the example yourself, create a text file that contains any unstructured text such as a chapter from a public domain book or article. We used a chapter from Burning Daylight, by Jack London which you can copy and paste into a text file. Or copy and paste it from here: Chapter One Burning Daylight, by Jack London. This will be used throughout the guide.
If you want to check out how to build a simple Android app from start to finish using Algorithmia check out this Android Sample App.
It is necessary to perform network operations (such as calling Algorithmia) on a background thread in Android, to avoid impacting UI performance. The standard way to acheive this in Android is to use an AsyncTask.
See Android documentation about UI vs. Background threads: Processes and Threads
Create a Data Collection
This section will show how to create a data collection which is essentially a folder of data files hosted on Algorithmia for free.
Import the DataDirectory object to work with data collections:
Now create a data collection called nlp_directory:
A Data URI uniquely identifies files and directories and contains a protocol “data://” and path “YOUR_USERNAME/data_collection”. For more information on the Data URI see the Data API Specification.
Instead of your username you can also use ‘.my’ when calling algorithms. For more information about the ‘.my’ pseudonym check out the Hosted Data Guide.
Work with Directory Permissions
When we created the data collection in the previous code snippet, the default setting is
DataAclType.MY_ALGOS which is a permission type that allows other users on the platform to interact with your data through the algorithms you create if you decide to contribute to algorithm development. This means users can call your algorithm to perform an operation on your data stored in this collection, otherwise the algorithm you created would only work for you.
To begin working with data directory permissions first add these imports:
Next check for the data collection’s permission type and update those permissions to private:
Notice that we changed our data collection to private, which means that only you will be able to read and write to your data collection.
Note that read access that is set to the default
DataMyAlgorithms allows any algorithm you call to have access to your data collection so most often, this is the setting you want when you are calling an algorithm and are an application developer.
For more information on collection-based Access Control Lists (ACLs) and other data collection permissions go to the Hosted Data Guide.
Upload Data to your Data Collection
So far you’ve created your data collection and checked and updated directory permissions. Now you’re ready to upload the text file that you created at the beginning of the guide to your data collection using the Data API.
Note: If you want to follow along and don’t wish to upload the file programatically you can upload Chapter One Burning Daylight, by Jack London file to your data collection by navigating to your Hosted Data and dragging and dropping the file into
First create a variable that holds the path to your data collection and the text file you will be uploading:
Next upload your local file to the data collection using the
This endpoint will replace a file if it already exists. If you wish to avoid replacing a file, check if the file exists before using this endpoint.
You can confirm that the file was created by navigating to Algorithmia’s Hosted Data Source and finding your data collection and file.
Downloading Data from a Data Collection
Next check if the file that you just uploaded to data collections exists, and try downloading it to a (new) local file:
This copies the file from your data collection and saves it as a file on your local machine, storing the filename in the variable
Alternately, if you just need the text content of the file to be stored in a variable, you can retrieve the remote file’s content without saving the actual file:
This will get your file as a string, saving it to the variable
input. If the file was binary (an image, etc), you could instead use the function
.getBytes() to retrieve the file’s content as a byte array. For more image-manipulation tutorials, see the Computer Vision Recipes.
Now you’ve seen how to upload a local data file, check if a file exists in a data collection, and download the file contents.
For more methods on how to get a file using the Data API from a data collection go to the API Specification.
Call an Algorithm
Finally we are ready to call an algorithm. In this guide we’ll use the natural language processing algorithm called Summarizer. This algorithm results in a string that is the summary of the text content you pass in as the algorithm’s input.
A single algorithm may have different input and output types, or accept multiple types of input, so consult the algorithm’s description for usage examples specific to that algorithm.
This example shows the summary of the text file which we downloaded from our data collection and set as the variable called
input in the previous code sample.
Create the algorithm object and pass in the variable
This guide used the the first chapter of Jack London’s Burning Daylight and the Summarizer algorithm outputs:
“It was a quiet night in the Shovel. The miners were in from Moseyed Creek and the other diggings to the west, the summer washing had been good, and the men’s pouches were heavy with dust and nuggets. MacDonald grinned and nodded, and opened his mouth to speak, when the front door swung wide and a man appeared in the light.”
If you are interested in learning more about working with unstructured text data check out our guide Introduction to Natural Language Processing.
Your account can make up to 80 Algorithmia requests at the same time (this limit can be raised if needed).
This guide covered installing Algorithmia via a Gradle dependencies file, uploading and downloading data to and from a user created data collection, checking if a file exists using the Data API, calling an algorithm, and handling errors.
For more information on the methods available using the Data API in Java check out the Data API documentation. For all available methods and versions go to the Algorithmia Android Client API Docs or view the Android Client Source Code.