Getting Started with Contentful and Android

This guide will show you how to get started using our Android client library to consume content.

Contentful's Content Delivery API (CDA) is a read-only API for retrieving content from Contentful. All content, both JSON and binary, is fetched from the server closest to a user's location by using our global CDN.

We publish client libraries for various languages to make developing applications easier.

Requirements

This tutorial assumes that you understand the Contentful data model.

Authentication

For every request, clients need to provide an API key, which is created per space and used to delimit applications and content classes.

You can create an access token using the Contentful web app or the Content Management API.

Create a new Android project

Create a new project in Android Studio using the 'Blank Activity' template, and name it whatever you wish.

Dependencies and permissions

This guide uses RXAndroid in the examples, which allows you to fetch results without tying up the main Android thread.

To include the CDA client library, add the following lines to the build.gradle file:

dependencies {
    // [...]
    compile 'com.contentful.java:java-sdk:9.0.1'
    compile 'io.reactivex.rxjava2:rxandroid:2.0.1'
}

Add the internet permission to the AndroidManifest.xml file so your app can access the Contentful APIs:

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
  package="com.example.demospaceexplorer" >

  <uses-permission android:name="android.permission.INTERNET" />
  ...
</manifest>

Creating a client

Add the following code to the onCreate method to create a CDAClient that communicates with the Contentful APIs:

Initialize the client

You need an API key and a space ID to initialize a client. You can use the API key and space ID pre-filled below from our example space or replace them with your own values.

CDAClient client = CDAClient.builder()
  .setSpace("<space_id>")
  .setToken("<access_token>")
  .build();

Use the Gson library to make JSON responses easier to read.

Gson gson = new GsonBuilder().setPrettyPrinting().create();

Fetching specific items

If you want to fetch a specific entry, use the id of the entry inside a .one method:

client.observe(CDAEntry.class)
    .one("<entry_id>")
    .observeOn(AndroidSchedulers.mainThread())
    .subscribeOn(Schedulers.io())
    .subscribe(new Subscriber<CDAEntry>() {
      CDAEntry result;

      @Override public void onCompleted() {
        Log.i("Contentful", gson.toJson(result));
      }

      @Override public void onError(Throwable error) {
        Log.e("Contentful", "could not request entry", error);
      }

      @Override public void onNext(CDAEntry cdaEntry) {
        result = cdaEntry;
      }
    });

I/Contentful: CDAEntry{id='<entry_id>'}

Fetching all data from a space

To fetch all entries, create a new observable that watches for changes, in this case, fetching all entries from the specified space with the all method and content type with the where method:

client.observe(CDAEntry.class)
               .where("content_type", "<product_content_type_id>")
               .all()
               .observeOn(AndroidSchedulers.mainThread())
               .subscribeOn(Schedulers.io())
               .subscribe(new Subscriber<CDAArray>() {
                   CDAArray result;

                   @Override
                   public void onCompleted() {
                       for (CDAResource resource : result.items()) {
                           CDAEntry entry = (CDAEntry) resource;
                           Log.i("Contentful", entry.getField("productName").toString());
                       }
                   }

                   @Override
                   public void onError(Throwable error) {
                       Log.e("Contentful", "could not request entry", error);
                   }

                   @Override
                   public void onNext(CDAArray cdaArray) {
                       result = cdaArray;
                   }
               });

I/Contentful: Hudson Wall Cup
I/Contentful: SoSo Wall Clock
I/Contentful: Whisk Beater
I/Contentful: Playsam Streamliner Classic Car, Espresso

The onNext method saves the array of entries and the onCompleted method is called once all entries are fetched from the API. The onError method allows you to handle any problems.