How to Handle JsonSyntaxException when Receiving Response from GAE

I made a previous post and appear to have made progress, but please see the StackOverflow post for reference: http://stackoverflow.com/questions/35068601/how-to-handle-jsonsyntaxexception-when-receiving-response-from-gae

I am trying to replicate the Google App Engine Servlets module [here][1] using Retrofit instead of AsyncTask.

I find it odd, but apparently Retrofit 2.0 does not support connections to Google App Engine, as stated [here][2] in the issues of the GitHub repository.

As a result, I am using Retrofit 1.9 and OkHttp 2.3 dependencies.

I have created a project called "Retrofit Test" in the Google Developer Console, and Google has supplied me with a URL for the project: "http://retrofit-test-1203.appspot.com" with the subdomain as "http://retrofit-test-1203.appspot.com/hello. These will be my respective URL's for Retrofit. Below is my code:

Gradle:

 apply plugin: 'com.android.application'

    android {
    compileSdkVersion 23
    buildToolsVersion "23.0.1"

    defaultConfig {
        applicationId "com.troychuinard.retrofittest"
        minSdkVersion 16
        targetSdkVersion 23
        versionCode 1
        versionName "1.0"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
     } 
    }

    dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    testCompile 'junit:junit:4.12'
    compile 'com.android.support:appcompat-v7:23.1.1'
    compile 'com.android.support:design:23.1.1'
    compile 'com.squareup.retrofit:retrofit:1.9.0'
    compile 'com.squareup.okhttp:okhttp:2.3.0'

    }

MainActivity:

public class MainActivity extends AppCompatActivity {

//set the URL of the server, as defined in the Google Servlets Module Documentation private static String PROJECT_URL = "http://retrofit-test-1203.appspot.com"; private Button mTestButton;

@Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar); setSupportActionBar(toolbar); mTestButton = (Button) findViewById(R.id.test_button);

//Instantiate a new UserService object, and call the "testRequst" method, created in the interface
//to interact with the server
mTestButton.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
        //Instantiate a new RestAdapter Object, setting the endpoint as the URL of the server
        RestAdapter restAdapter = new RestAdapter.Builder()
                .setEndpoint(PROJECT_URL)
                .setClient(new OkClient(new OkHttpClient()))
                .build();

        UserService userService = restAdapter.create(UserService.class);
        userService.testRequest("Test_Name", new Callback<String>() {
            @Override
            public void success(String s, Response response) {
                Toast.makeText(getApplicationContext(), s, Toast.LENGTH_LONG).show();

            }

            @Override
            public void failure(RetrofitError error) {
                Toast.makeText(getApplicationContext(), error.getMessage(), Toast.LENGTH_LONG).show();
            }
        });
    }
});

} }


UserService (Retrofit)

public interface UserService {

@POST("/hello")
void testRequest(@Query("name") String name, Callback<String> cb);

}

My Servlet:

public class MyServlet extends HttpServlet { @Override public void doGet(HttpServletRequest req, HttpServletResponse resp) throws IOException { resp.setContentType("text/plain"); resp.getWriter().println("Please use the form to POST to this url"); }

@Override public void doPost(HttpServletRequest req, HttpServletResponse resp) throws IOException { String name = req.getParameter("name"); resp.setContentType("text/plain"); if(name == null) { resp.getWriter().println("Please enter a name"); } resp.getWriter().println("Hello " + name); } }



As you can see, I have set the project up so that I make a server request on a button click. Similar to the Google App Engine Servlets module, I am expecting to receive a response from the Server, which I then display as a Toast that says "Hello + (whatever parameter entered into the .testRequest() method, which is "Test_Name" in this case.

GoogleCloudPlatform / gradle-appengine-templates

How to Handle JsonSyntaxException when Receiving Response from GAE #64