How can I use from GraphQl in android?

问题

I need to a simple example for use GraphQl in android .

How can I use from GraphQl in android (tutorial).

回答1:

In order to use GraphQL (in general), you need two things:

1. A GraphQL server

There are a few ways how you could go about this. Of course, you could simply go and implement one yourself in any server-side language you like. Other (faster) approaches are to take advantage of existing tooling and generate a GraphQL API using services like graphql-up or create-graphql-server or even services like Graphcool (disclaimer: I work for them).

2. A GraphQL client library

Though this one isn't strictly necessary and you could also simply interact with the GraphQL server through plain HTTP (sending your queries and mutations in the body of POST requests), it is certainly beneficial to use existing tools that take repetitive work like caching or UI integrations off your shoulders. One of the most popular GraphQL clients right now is Apollo, and they're very actively working on a version for Android as well. However, this hasn't been officially released yet. So, you either have to use their existing development version of chose the former approach using plain HTTP for now.

回答2:

Here is an example of querying GraphQl from Client. In this example I am using Retrofit 2:

// QueryHelper.java
// This line below is the simple format of Gql query
query = "query{me{name, location, majorOfInterest,profilePhoto{url(size: 400) }}}";

//Post the query using Retrofit2
GqlRetrofitClient.getInstance(getContext()).fetchUserDetails(new GqlQueryRequest(queryUserDetails)).enqueue(new Callback<UserDetails>() {
  @Override
  public void onResponse(Call<UserDetails> call, Response<UserDetails> response) {
     //OnResponse do something();       
     }

  @Override
  public void onFailure(Call<UserDetails> call, Throwable t) {
    Log.d(TAG, "Failed to fetch User details");
    }
    });


//GqlClient.java
public class GqlRetrofitClient {
public static final String BASE_URL = BuildConfig.DOMAIN;
private static GqlRetrofitClient sInstance;
private GqlRetrofitService mGqlRetrofitService;

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

  private GqlRetrofitClient(final Context context) {
    // Network Interceptor for logging
    HttpLoggingInterceptor httpLoggingInterceptor = new HttpLoggingInterceptor();
    httpLoggingInterceptor.setLevel(HttpLoggingInterceptor.Level.BODY);

    OkHttpClient okHttpClient = new OkHttpClient.Builder()
            .addNetworkInterceptor(new Interceptor() {
                @Override
                public Response intercept(Chain chain) throws IOException {
                    Request request = chain.request().newBuilder()
                            .addHeader("X-User-Token", "AUTH_TOKEN")
                            .addHeader("X-User_Email", "Email")
                            .addHeader("content-type", "application/json")
                            .build();
                    return chain.proceed(request);
                }
            })
            .addInterceptor(httpLoggingInterceptor)
            .build();

    // Retrofit initialization
    final Retrofit retrofit = new Retrofit.Builder()
            .baseUrl(BASE_URL)
            .addConverterFactory(GsonConverterFactory.create(gson))
            .client(okHttpClient)
            .build();

    mGqlRetrofitService = retrofit.create(GqlRetrofitService.class);
 }

  // Create an instance of GqlRetrofitClient to create retrofit service
  public static GqlRetrofitClient getInstance(Context context){
    if(sInstance == null){
        sInstance = new GqlRetrofitClient(context.getApplicationContext());
    }
    return sInstance;
  }

  // Method call to get User details
  public Call<UserDetails> fetchUserDetails(GqlQueryRequest queryUserDetails){
    return mGqlRetrofitService.getUserDetails(queryUserDetails);
  }
}

//GqlRetrofitService.java
public interface GqlRetrofitService{
  @POST("/api/graph.json")
  Call<UserDetails> getUserDetails(@Body GqlQueryRequest body);
}

来源：https://stackoverflow.com/questions/43292529/how-can-i-use-from-graphql-in-android