Examples.java

public interface RegistrationAPI {
@FormUrlEncoded
@POST("/ServerBackyard/insert_details.php")
public void addUser(
        @Field("email") String email,
        @Field("name") String name,
        @Field("username") String username,
        @Field("password") String password,
        Callback<Response> callback);
}

private void addUser(){
    RestAdapter adapter = new RestAdapter.Builder()
            .setEndpoint(BASE_URL) //Setting the Base URL
            .build();

    RegisterAPI api = adapter.create(RegistrationAPI.class);
  
    api.addUser(

            editTextEmail.getText().toString(),
            editTextUsername.getText().toString(),
            editTextPassword.getText().toString(),
            editTextName.getText().toString(),
      
            new Callback<Response>() {
                @Override
                public void success(Response result, Response response) 
                    BufferedReader reader = null;
                    String result = "";

                    try {
                        reader = new BufferedReader(new InputStreamReader(result.getBody().in()));
                        output = reader.readLine();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                    Toast.makeText(MainActivity.this, result, Toast.LENGTH_LONG).show();
                }

                @Override
                public void failure(RetrofitError err) {
                    //If any error occured displaying the error as toast
                    Toast.makeText(MainActivity.this, err.getMessage,Toast.LENGTH_LONG).show();
                }
            }
    );
}