Sending JSON in POST request with Retrofit2
<p>I'm using Retrofit to integrate my Web services and I do not understand how to send a JSON object to the server using a POST request. I'm currently stuck, here is my code:</p>

<h2>Activity:-</h2>

<pre><code>@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);


    Retrofit retrofit = new Retrofit.Builder().baseUrl(url).
            addConverterFactory(GsonConverterFactory.create()).build();

    PostInterface service = retrofit.create(PostInterface.class);

    JSONObject jsonObject = new JSONObject();
    try {
        jsonObject.put("email", "device3@gmail.com");
        jsonObject.put("password", "1234");
    } catch (JSONException e) {
        e.printStackTrace();
    }
    final String result = jsonObject.toString();

}
</code></pre>

<h2>PostInterface:-</h2>

<pre><code>public interface PostInterface {

    @POST("User/DoctorLogin")
    Call&lt;String&gt; getStringScalar(@Body String body);
}
</code></pre>

<h2>Request JSON:-</h2>

<pre><code>{
"email":"device3@gmail.com",
"password":"1234"
}
</code></pre>

<h2>Response JSON:-</h2>

<pre><code>{
  "error": false,
  "message": "User Login Successfully",
  "doctorid": 42,
  "active": true
}
</code></pre>